2 stroke comeback.

[Jeff B]

Quite a few teething problems to sort through.
Couple water leaks on engine, bolts missing, off gasket missing.
Not charging, not sure if regulator, stator or wiring,
Tacho bounces around, could be sign of bad stator/wiring?
Engine bogs off idle, is inconsistent, surges. If idle for too long it bogs really bad.
Carbs getting fuel standoff much above half throttle.

I suspect I'm pumping too much water into exhaust chamber, currently all of it including over pressure dump which is quite a lot.
I'll experiment with restricting it and see what difference it makes.
Might make a different exhaust chamber to try as well, longer and fatter.

[wad26]

You dont think fuel is pooling in your long swoopy intake at low RPM and then coming through in blobs? This is the problem we have when bolting a carby straight onto the Subaru intake manifold. It caused very inconsistent running 

[Jeff B]

You dont think fuel is pooling in your long swoopy intake at low RPM and then coming through in blobs? This is the problem we have when bolting a carby straight onto the Subaru intake manifold. It caused very inconsistent running 

I dont think so but it could be a possibility? Can idle for quite a while out of water and snap throttle it revs quickly.
Need to sort through everything and make sure tps, crank sensor etc are working properly before major re designs..

[Jeff B]

On a positive note, the 3 minute run I did get in, the hull felt good, and the pump also felt good, hooked up and no vibrations or noise, well none that were noticed above the engine noise and vibrations anyway....

[Ross Goldsack - JBNZ Immediate Past President]

Jeff, you've certainly got your finger on it aye!

Tell us this story......

[Jeff B]

Jeff, you've certainly got your finger on it aye!

Tell us this story......

Ouch, that looks sore Ross....that's what happens when you stick your finger In a flywheel while engine running.
Never mind, the finger gets the same type of band aid fix as my boat....
Good as new.

[Jeff B]

Made an intake for carbs, they are a bit low and in the unlikely event that I take on water I dont want them.suckung it into engine.
Was a bit hard welding one handed and I contemplated sub contracting it out to mohawk marine or Ross racing but ended up feeding wire with toes for a better outcome....

[Jeff B]

Gaskets kept falling off so I stuck them on with sticky silicone.
I'll go find some type of high performance air filter I can bung on the top.

[mallyxt]

Jeff
What is the water over pressure dump you are using
Looking for something to protect my intercooler when i put the extra stage on my unit
 

[Jimmy Jet]

I'm in agreeance with the exhaust water volume Jeff. All my eggbeaters over the years of 135, 150 and 225hp have all had less water coming out the exhaust hub than you would expect. Restricting it could be a good start. Or a fully jacketed chamber?

[Jeff B]

Swapped voltage regulator but still not charging so I'm guessing it's the stator charge coils? Just a 2 phase alternator.

[Jeff B]

I'm getting what I think is a terrible misfire at about 4000rpm. I did get this engine cheap with no spark and a suspected stuffed ecm or stator so spark possibility. Although I have stuffed with a lot of things so could be fuel?
Starts and idles fine out of water, has a tiny flat spot. Not sure if idle on allot not? But in the water if I idle it for too long it bogs badly, like a lean bog, i have to choke it to rev up, then when revs rise it poofs out a heap of smoke and takes off. This leads me to suspect what William mentioned, fuel pooling in my intake manifold? It's got a few bends so possibly it is a terrible intake design for carburettors?

[Paul]

Weld a stainless pipe with cooling water running through it, across the intake runners - so that it'll keep the runners warm enough that no fuel can condense out.  If that doesn't help, you can just disconnect that coolant flow through the pipe, so the intake charge is not being heated too much.

Don't forget that stainless is really bad at 'heat transfer' (- a lot worse than copper or ali), so it can be fairly warm, without much energy going into the intake charge.

[Allen M]

I'm getting what I think is a terrible misfire at about 4000rpm. I did get this engine cheap with no spark and a suspected stuffed ecm or stator so spark possibility. Although I have stuffed with a lot of things so could be fuel?
Starts and idles fine out of water, has a tiny flat spot. Not sure if idle on allot not? But in the water if I idle it for too long it bogs badly, like a lean bog, i have to choke it to rev up, then when revs rise it poofs out a heap of smoke and takes off. This leads me to suspect what William mentioned, fuel pooling in my intake manifold? It's got a few bends so possibly it is a terrible intake design for carburettors?

I?d be looking at your exhaust system for a start.2strokes are very sensitive to exhaust pulses.
In the water the engine will be under more load, even when ideling and your engine could be loading up with exhaust fumes from the reverse pulses going on in an overly restrictive system.
Try running it with an open Pipe to eliminate this.
Any self respecting metal fabricator would have a set of tuned and jacketed chambers on it anyway 
Might as well add TPInjection. That will sort the carbs out once and for all

[Jimmy Jet]

100% agree with Allen M on the exhaust.