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nzjetboating.com Forums => Projects => Topic started by: wad26 on May 13, 2020, 09:26:28 AM

Title: Daewoo Powered Plastic Jet
Post by: wad26 on May 13, 2020, 09:26:28 AM
Following the completion of my last plastic boat (powered by a subaru) and with lockdown looming i thought to myself... could i build a more unreliable jet boat??

Following the trip to the neighbours paddock i found the answer, a 1998 Deawoo Nubira!

Then my old man decided if we are building one boat, might as well build one each.

Specs: Boat 1 (The Schist)

1.6l Daewoo engine on car ecu
155mm seadoo pump
3.3m Plastic hull
14 degree deadrise
1500 chine to chine
Aiming for sub 350 kg

Boat 2

Ej20 running Webber carb and Toyota distributer
Single stage Colorado junior
Same hull as above
Aiming for sub 400 kg


Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on May 13, 2020, 14:50:24 PM
Cool! New projects- get them pics flowing!  *-)
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 14, 2020, 15:22:35 PM
Tried something a bit different on this one due to the lockdown and used an OHP to mark the cut lines. Worked surprisingly well, just had to make sure it was very square...
Title: Re: Daewoo Powered Plastic Jet
Post by: Matthewf/Norbert/TuiDog on May 14, 2020, 17:09:25 PM
Nice use of older ohp  tech B))T
Title: Re: Daewoo Powered Plastic Jet
Post by: Reid01 on May 15, 2020, 00:43:23 AM
Excuse my ignorance but what?s ohp? Also could you tell me about your welding machine and what grade of plastic your using? Your other boat looks great by the way
Title: Re: Daewoo Powered Plastic Jet
Post by: Markg on May 15, 2020, 07:44:46 AM
Excuse my ignorance but what?s ohp? Also could you tell me about your welding machine and what grade of plastic your using? Your other boat looks great by the way
Over head projector
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 15, 2020, 08:35:36 AM
The welder is an extrusion plastic welder (probably best to google from there) The brand is a Leister and its darn expensive.
The process is somewhat simple, the plastic is cut to shape and then the surface is scraped clean just before welding. The welder squirts out what looks like plastic toothpaste and it takes about 10 mins to cool and gain full strength.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 15, 2020, 08:47:24 AM
Having only every worked with Hamilton units before these Jetski beasts are all new to me. For now im just slapping the ski impeller in and a new plastic wear ring in for initial trials. I realize this will likely require an upgrade in the future.

Also note the Daewoo racing department high performance donor car fl.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on May 15, 2020, 08:54:58 AM
Cool project.
I think the Daewoo and seadoo parts will work well together?
What's your crankshaft to driveshaft coupling?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 15, 2020, 09:25:52 AM
Funnily enough that's the one part preventing a water test at the momenet...

Plan is to use the original Seadoo rubber coupling, machine the female spline off the engine half and bold it directly to the flywheel. This inspired by a pic Lazy sent me of his setup.

Is there a better way?
Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on May 15, 2020, 13:40:49 PM
The welder is an extrusion plastic welder (probably best to google from there) The brand is a Leister and its darn expensive.
The process is somewhat simple, the plastic is cut to shape and then the surface is scraped clean just before welding. The welder squirts out what looks like plastic toothpaste and it takes about 10 mins to cool and gain full strength.

what model number are you working with?
Title: Re: Daewoo Powered Plastic Jet
Post by: MRM on May 19, 2020, 21:19:58 PM
Cool project.
I think the Daewoo and seadoo parts will work well together

Do is it a daedoo or a seawoo?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 20, 2020, 08:05:33 AM
Im not making a call on the poo vs woo debate until it hits the water...

Here is another update.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on May 20, 2020, 12:36:07 PM
I'm thinking.
"Woodoo"   or
"Woodle" ?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on May 28, 2020, 13:58:35 PM
So this week i finally got the driveshaft adapter all sorted. Daewoo flywheel bolts are not evenly spaced (only goes in one position) so it was come fun and games to make.
With that the engine was aligned and bolted in properly for the first time. Plugged in all the hoses and wires and...

It goes!!

Purrs like a kitten actually. I'm waiting for the seat to come back from getting covered but i don't think that will stop me going for a water test this week.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 05, 2020, 08:28:40 AM
Not sure if its frowned upon to have Ham jet logos on a Seapoo?  )1
Title: Re: Daewoo Powered Plastic Jet
Post by: Warwick Marflitt on June 05, 2020, 13:25:29 PM
"The seats" like Hamilton jet! Lead the way... The SeeLoo knows.... Who spread the waves.. pushing aside gravel n stones "Up and beyond" following Hamilton's Rapid advancements n successions.......

 I drove at the rapids sometimes as if in a dream, heart pumping and engine thumping, looking ahead at the ridiculous step-ladder of muddy water; climbing up it incredulously not believing that any of this could really, or was really happening. Vulcan Rapid (Lava Falls) was the greatest thing on the river. We used fifty gallons [189 litres] of gasoline in the engines to get the boats over the hill, it is 400 yards long and rises about 20 feet in that distance.

It took Jon Hamilton two days to take four boats over the Vulcan Rapid, spending as much as half an hour to climb up individual standing waves.

Stolen from
https://www.nzgeo.com/stories/bill-hamilton/
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 16, 2020, 16:38:47 PM
So I finally Hit the water!

The Daewoo has power to burn, Im hitting the rev limiter (7000 ish rpm) with the standard impeller. I need to work out what pitch i have and get a coarser one to tame the Woo!

Even in its current state it gets on the plane well with three people which im happy with.

BUT... it porpoises.... Bad!

I will start with a ride plate at the rear, however i am concerned it is too beamy for its length and the COG may be too far forward...

Much more trial an error required. Has anyone else had bad porposeing in small boats? What fixed it?
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 16, 2020, 17:03:31 PM
Maybe check your impeller is in good nick? That poodoo 951 pump should be sucking up 130 odd [email protected] 7000rpm.
So possibly the mighty Woo is pumping out 20hp more than factory claimed (I'm not really believing this) or your pump is a bit sad? (Doesn't take much for these high performance setups to go "off")
Porposing is one of those things that is caused by a few different things.  Sometimes adding planing/lifting strakes helps a lot. 2c
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 17, 2020, 07:44:15 AM
So the impeller should be basically rubbing? There is currently a small gap (would be totally fine in hamilton unit) but i suspect this needs rectifying.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 17, 2020, 10:22:24 AM
So the impeller should be basically rubbing? There is currently a small gap (would be totally fine in hamilton unit) but i suspect this needs rectifying.

i guess it depends on your definition of 'small gap' is?
To be honest, 9 out of 10 second hand ski pumps i come across are not within factory tolerance specs. 0.5mm is getting on the looose side for a ski pump.
Yet a Hamilton pump seems to have 0.5mm clearance as soon as its been run for a few hours and even 1mm doesnt seem to affect them much. 2c
Title: Re: Daewoo Powered Plastic Jet
Post by: Henry on June 17, 2020, 10:51:04 AM
Check you tail cone/nozzle isnt trimmed up. Often you can flip them 180degrees to experiment.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 18, 2020, 11:46:00 AM
I have got a trim nozzel set up with has a very large range of trim angles. With it trimmed hard down or close to it the porpoising will stop but at that point its running on its nose and top speed is terrible...

Im beginning to think (after much reading of research papers) I have too much lift in the rear for its length (its 1500 ctc and 3.3m long..). This puts the center of lift well back and the COG well forward repetitively speaking.

I will try a ride plate and planing strakes initially as they are easy. Otherwise i may look at some slalom chines like the old Hamiltons to take some lift out of the rear.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 18, 2020, 13:35:23 PM
Wont putting a ride plate on/extending bottom back move your effective COG forward?  ::) ii
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 18, 2020, 14:00:46 PM
It shouldn't move the COG, if anything it would move it slightly further back but it will be lightweight plastic  :P

It will move the Center of lift back though with is wrong direction from what I've read... But its easy and i want to experiment and try to understand whats going on :) 
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on June 18, 2020, 15:23:57 PM
More lift in the rear will stop porpicing or help... dunno what youve been reading too convince you othewise ?
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 18, 2020, 16:08:11 PM
It shouldn't move the COG, if anything it would move it slightly further back but it will be lightweight plastic  :P

It will move the Center of lift back though with is wrong direction from what I've read... But its easy and i want to experiment and try to understand whats going on :)

I'm not really understanding this logic?
If you extend the bottom back of the boat by....let's say 300mm. You have made the whole boat 300mm longer (when planing) so you have made the boat longer but not really added much weight. All the weight is forward now so in theory your COG has moved forward by approx 150mm?
Moving weight forward stops porposing.
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on June 18, 2020, 19:18:58 PM
I'm not really understanding this logic?
If you extend the bottom back of the boat by....let's say 300mm. You have made the whole boat 300mm longer (when planing) so you have made the boat longer but not really added much weight. All the weight is forward now so in theory your COG has moved forward by approx 150mm?
Moving weight forward stops porposing.
exactly
Title: Re: Daewoo Powered Plastic Jet
Post by: Paul on June 18, 2020, 20:03:15 PM
Wad and Jeff are both right, just expressing it differently. Adding a kilogram(?) of ali to a 500kg boat for a ride plate, is going to make essentially no difference (0.2%) to the CoG (- the boat is now 501KG). However, by extending part of the running surface rearwards, moves the CoL (Centre of Lift) rearwards. By the CoL being further apart from the CoG, increases the pitch-down turning moment, so the boat trims more bow down.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 19, 2020, 06:55:08 AM
Thanks Paul, good explanation.
So I guess a longer planing area is always going to be more stable, less likely to porpose than a shorter one. And a more efficient fix than pushing the rear up/nose down using trim nozzle?
I did some testing with a std jetski trim nozzle and much more than 5 deg up or down from centre it actually started to reduce thrust. Trimmed up more than 2/3 up trim and top speed actually slowed down (on my boat) the extra up trim didnt make up for the loss of thrust of deflector trim nozzle.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 19, 2020, 07:40:38 AM
Thanks Paul, you put my thoughts into mush better words  b>

I definitely will try the ride plate, I will report back on its effect. B))T

Title: Re: Daewoo Powered Plastic Jet
Post by: Henry on June 19, 2020, 09:32:06 AM
As Jeff said the jetski trim nozzle doesn't do much and will kill performance at large angles. Angling the tail cone down is much more effective and wont kill performance.

Its probably not the issue but you can check the tail cone angle just by looking at it so no reason not to check it.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 26, 2020, 09:00:27 AM
Interesting, i feel there could be a nozzle upgrade not too far away. If not only is it inefficient at large trim angles and steering angles but the feel is terrible compared to a ball in socket...

On a side note work is continuing on the Daewoos twin.

-Started with a Webber 32/36 off a Granada v6 as per the pic below. This was terrible with 2 cylinders running rich and 2 lean due to the 90 degree bend.
- Next went for a side draft Rover carb. This went much better but still not right..

-Have now given up, thrown the original intake manifold away and bought a pair of 40mm Webber down draft carbs like Jeff said right from the beginning....

Have also ordered a SACO tapered hub impeller from Sean, really excited to see what we can get out of this little single stage that everyone says will never go any good  B))T
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 30, 2020, 08:29:05 AM
Thought i'd put this bad boy on there last night. Should be plenty to pull a putsy 2 stroke or more likely my subaru after another head gasket failure...

Ignore my cuzzy customs engine cover, its for testing purposes only
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on June 30, 2020, 09:34:35 AM
I like that fold down aerial. Might have to get one.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on June 30, 2020, 09:39:19 AM
They are on sale for $60 at the moment, made in NZ, cant go wrong.

I need to coms so i can get help when the woo lets me down...
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on July 06, 2020, 07:39:47 AM
So the Mrs was away for the weekend so i rounded up the old boy and we build some trailers. 2 trailers in a weekend wasn't bad going I thought.

Have just flogged the wheels off the Daewoo as its last dieing gift. Having now taken all I need from it it now free to a good home  :P

Now the trailers are built we will get back to fitting the downdraft webbers on the suby, my $100 new jetski impeller for the woohoo has arrived so hopefully that can tame the beast!
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on July 28, 2020, 07:40:27 AM
Although there haven't been many posts recently i have been busy.

Trailers are all painted, warranted and registered.

I build a ride plate under the unit as per the attached picture. This has transformed the handling of the boat. it no longer proposes and sits very well on the water IMO.

In the weekend i took it for a couple of hour run up our local Waitara river. The little Daewoo sat at 90 degrees the whole way (i was concerned my heat exchanger could be too small) and ran like a dream.

I still need to set up my reverse bucket and my spare impeller is currently getting its OD built up which i'm hoping will make a big difference and bring the RPM down.

https://www.youtube.com/watch?v=Zjs0uH63a60

PS. you will notice it is missing (quite badly) in the vid, this was found to be a loose power supply to the ecu and was soon resolved...
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 18, 2020, 08:43:23 AM
The Daewoo is sick  C""

I need some held from all of you EFI brains out there.Over the last few test runs the mighty Daewoo has developed a misfire at mid throttle.

The symptoms are:
-Starts perfectly
-Idles perfectly
-intermittent misfire at part throttle, sometimes its fine for half an hour, then will play up for a few mins and then be okay again
-can power out of it, ie it will somewhat clear with more throttle.
-Have replaced the spark plugs, the all looked the same, all dark ad sooty (running rich?)
-Have tested all plug leads

o2 senser? MAP senser? MAF senser? a poor connection in my wiring?

Thoughts?
Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on August 18, 2020, 09:10:11 AM
If its running rich then could easily be the 02 sensor- grab a couple of second hand ones and try them first. If you have a wideband or can borrow one that would be a good place to start- bung it in the same hole- will help eliminate the fueling as an issue or identify the area to focus on. I would also check grounds- msifires or intermttant missing can be caused by poor signals and it makes ecu's very unhappy. good luck and post your results.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 18, 2020, 09:12:15 AM
Cheers, I hadn't thought of putting the wide band in. I'll try that tonight. b>
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on August 18, 2020, 09:23:09 AM
Sooty plugs tell you it's either running rich. Or spark is breaking down and plugs aren't igniting the mixture.
Could be a number of things?  Did you wire in the diagnostic plug? I'm guessing if you do get a read on it there will be all sorts of fault codes....
But some things to check,
Temp sensor. If this is  playing up or broken wire the ecu thinks temp is freezing cold and dumps fuel in (rich)
MAP or air flow meter. Same again, that's what ecu uses to measure air volume into engine so squirts fuel in to match. If sensor is faulty, fuelling is off.
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on August 18, 2020, 10:39:53 AM
Makes carbs sound so much simpler  ii
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 18, 2020, 11:00:56 AM
Yes i always knew this would be the risk of copy pasting the car setup. 02 senders are $70 and on the shelf so ill chuck one of those in. Ill have a very close look at the tube running to the MAP senser and make sure there are no leaks there and check the wiring to the engine temp senser.

Failing that i think it will have to go through my wiring more thoroughly and check all earths and power supply to the ECU.
Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on August 18, 2020, 13:49:34 PM
My thought is its fueling not spark- if it were breaking down under load then for sure electical, you state it clears its throat when you give it the jandle- thats a rich condition I think- Jeff has put you onto the temp sensor - this could be an easy fix. Are you an HE or raw water- a stuck open thermostat could be fooling the ecu into richening up the mixture?
Map sensors etc do fail so I would start replacing them one by one if you can afford it. Another option is to take it to an auto sparky and get them to run it up on the oscilloscope- see if you have bad grounds or intermittant signals?
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on August 18, 2020, 14:00:38 PM
Replacement new sensors and this talk of auto sparky charge out rate is not gunna make the $100 woo owner happy.... C""
Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on August 18, 2020, 14:49:07 PM
Thats why I hate ECU's they are awesome until they are not. Carbs are awesome-ish and tend to stay that way. I have drunk the Mohawk Koolaid  cou
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 18, 2020, 15:43:47 PM
Its running a H/E and site on 80 degrees perfectly so i dont think there is any issue there.

The more i think about it i'm dubious about the tube to the MAP senser, could have easily poped off or be leaking.

I,ll have a look tonight and take it for a spin. Fingers crossed. Its goes really well when its right...
Title: Re: Daewoo Powered Plastic Jet
Post by: MRM on August 18, 2020, 20:51:38 PM
You should be able to just unplug the o2 sensor and it'll go back to the base map.
Could be an easy way to test?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 19, 2020, 07:30:49 AM
A wise man once told me, if you fix the simple things, the weird problems go away...

Replaced this lead, took it for a burn and I've never heard a Daewoo run so sweet!

Bit embarrassed i didn't spot this sooner  sh
Title: Re: Daewoo Powered Plastic Jet
Post by: Kakapo76 on August 19, 2020, 08:10:11 AM
Great result! Thanks for posting.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on August 19, 2020, 08:56:14 AM
Is that spark plug lead to one cylinder? Or dizzy?
So it was the spark not igniting mixture?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 19, 2020, 09:32:52 AM
It was just to one cylinder, but when i was shorting out the plugs to fault find it was doing all sorts of crazy things. They all come from one coil pack and it was shorting to ground. I'm assuming its a wasted spark system so that one cylinder was affecting the others.

While I was at it I checked all the other possibilities - air leaks, MAP tubes, loose connections etc etc and couldn't see any other issues.

The only thing i haven't done is recheck the plugs to see what they look like, I'll do that soon and post a pic
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on August 19, 2020, 10:17:06 AM
Dont feel too bad...
Mohawk and Kakapo would have the same issues with a carb and dizzy....
You must be close to gathering some performance data?
There will possibly be some lurkers watching, ready to purchase (or pick up abandoned ones) Daewoo donor cars.. ::)
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 19, 2020, 10:33:35 AM
So current performance data is not spectacular, 60 km/h at the rev limiter (estimated 6200rpm?).

Bear in mind this is with the impeller with 0.8 mm od clearances. I'm still working on building up my spare impeller to a racing tolerances.

Hopefully the tight clearances will up the speed and pull back the WOT rpm (i need to get the rev counter sorted) but i think 5800- 6000 would be nice.

Title: Re: Daewoo Powered Plastic Jet
Post by: Ross Goldsack - JBNZ Immediate Past President on August 19, 2020, 18:53:04 PM
The woowoo works out at a pretty good Kph/$  b>
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on August 21, 2020, 19:39:37 PM
So current performance data is not spectacular, 60 km/h at the rev limiter (estimated 6200rpm?).

Bear in mind this is with the impeller with 0.8 mm od clearances. I'm still working on building up my spare impeller to a racing tolerances.

Hopefully the tight clearances will up the speed and pull back the WOT rpm (i need to get the rev counter sorted) but i think 5800- 6000 would be nice.
155 mm pump or 159 ?
 
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on August 24, 2020, 08:33:44 AM
155 mm pump with 0.8mm gab around the impeller  ;D
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on September 17, 2020, 10:01:07 AM
Bit of an update on the intermittent misfire.

I replaced the O2 senser a couple of weeks back, this resulted in one good run with no issues before the missfire returned.

The weekend before last i was on a club run and the missfiring became so bad it almost caused the engine to cut out.

In desperation I just unplugged the O2 senser all together.

I have since done 4 hours boating without a single missfire. I have also pulled a spark plug and to my eye it looks good so i think the mixture is pretty good. On closer inspection it is clear that i have mounted the senser too close to where the water enters the wet section of the exhaust (75 to 100 mm) and its getting wet.

From what i have read about older EFI systems the O2 senser is only used to adjust the fuel trim in light load "cruise" situations for good fuel economy. This is a situation which almost never happens in the boat so i think i will just leave it unplugged.
Title: Re: Daewoo Powered Plastic Jet
Post by: Henry on September 17, 2020, 11:51:24 AM
When i did my SR20 boat i did a one time "tune" with a wide band sensor in the exhaust and an adjustable fuel pressure regulator.

Drove around while the tuner guy adjusted the fuel pressure until the fuel ratio was close to ideal.

Gained a fair bit of power and economy as the stock system often runs rich in a boat where it's running blind with lots of sensors removed.
Title: Re: Daewoo Powered Plastic Jet
Post by: MRM on September 17, 2020, 13:22:06 PM
That's a good idea actually.
Could you bleed a little of the vacuum going to the fpr to drop the pressure?

If you're not already tuning it on 91 then, since it'll be nice and rich, you can probably do that to bring the cost per hour down.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on September 17, 2020, 13:53:40 PM
That is a good idea indeed. I've got a wide band so i could play around with that.

Before i go trying to make more power however I was to make some improvements on my unit.

Even with the impeller a rubbing fit its still pulling will north of 6k rpm. After some discussions with a local boater around here i'm thinking about wizzing up a thinner wear ring and building up my impeller further to say 159 or 160 mm diameter as an alternative to a coarser pitch.

I have a spare unit so i can do this and compare the two, has anyone else done something similar? what were the results?
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on September 17, 2020, 22:37:35 PM
dont the 155 and 159 /160 seadoos have the same ring , just different IDs
My impellar housing is a 160mm seadoo wear ring with a 1.2mm wear ring inside that ... i run the bigest seadoo blades spun down too 157ish , and the trailing edge pitched up quite abit.

Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on September 18, 2020, 07:50:06 AM
Yes I did this to a Seapoo pump. Took a 159mm impeller and welded 1/8" 2209 duplex round bar around the OD then turned it down. This gave the OD (wear zone) a fatter edge. Diameter enlarged to 163mm.
Skimmis out the plastic wear ring and knocked in a 1.2mm stainless one.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on September 18, 2020, 08:54:52 AM
That's exactly what i had in mind.

Was it any good?
Title: Re: Daewoo Powered Plastic Jet
Post by: MRM on September 18, 2020, 09:29:57 AM

Could you bleed a little of the vacuum going to the fpr to drop the pressure?


Sorry, ignore that bit. Bleeding vacuum will increase the fuel pressure. I was thinking of turbo cars.
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on September 18, 2020, 11:24:30 AM
That's exactly what i had in mind.

Was it any good?

Dunno? I never got to test it, I sold the Suzuki (old news)  powered boat before I got to test it.
I would say test it on your woodoo but splined are bigger I  the 159mm seadoo impellers
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on September 18, 2020, 12:17:02 PM
Easy enough too add 2mm though... ive pulled about 200 rpm out of a stock blade by just pitching it up but its how it feels all the way thru the rpm range you notice most
Title: Re: Daewoo Powered Plastic Jet
Post by: mohawk on September 18, 2020, 12:22:13 PM
Ive got a big hub 155 here if you need one... $150
The 4 different 157s i have all needed more pitch too keep the r18 around 6000
Title: Re: Daewoo Powered Plastic Jet
Post by: Jeff B on September 18, 2020, 12:25:17 PM
Good comparison.
Mohawks R18 probably making similar power to the woodoo?
Do you have an accurate tacho?
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on September 18, 2020, 13:05:24 PM
No i don't have a accurate tacho yet, been working on it this week. I've got an old tacho that i had lying around but it wont talk to the hi tech Daewoo ecu.
I've taken it to the gauge specialist to make them talk to one another.

My google research suggests that the rev limiter is at around 6700 rpm though.
Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on October 28, 2020, 09:59:33 AM
Update on the Subaru twin

Steady improvements have been going on in the background with the Daewoos reliable twin.

The impeller from Sean at Saco had been fitted and what a difference!! There is absolutely no slip under any circumstances, hole shot, full power turning etc. I would say it hold on as well as my Hamilton 2 stage (with less power obviously).

At 4950 rmp we are getting 58 km/h on the GPS with a 106 mm nossel. The hole shot currently is ridiculously good so we will experiment with a smaller nossel. Sean has also suggested de-pitching the blade slightly to get the RPM higher which we will also try.

This boat has really struggled with proposing from day 1 and nothing has really made a difference, until now. Out of desperation we welded a 250 mm hull extension. This has improved every accept of the boat, it does not porpose at any trim angle now, turns better, planes slower and top speed is up by 1 km.

I believe this has come about because when the 3.8 m hull was redesigned to make these 3.3, the bow section was largely unchanged leaving a very short constant dearise section at the rear of the boat. Maybe?

Title: Re: Daewoo Powered Plastic Jet
Post by: wad26 on April 14, 2021, 11:09:05 AM
Ive finally started upgrading my seapoo 155mm pump to 165mm monster.
Out with the putz plastic wear ring and in with a 2mm stainless one.
Welded 6mm rod around the old impeller.
Now its just time for some machining, grinding and probably some balancing...
Title: Re: Daewoo Powered Plastic Jet
Post by: Ross Goldsack - JBNZ Immediate Past President on April 14, 2021, 20:41:46 PM
You'll have to hot up Woowoo to spin that huge angry impeller....