2 Stroke Engine dies

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TRidge

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I have an old Vire 2 Stroke in an equally old sail boat. Its a single cylinder, 6hp, which now has the habit of starting quite easily, and running well, but after approx 15 mins stops with no warning, and will not re-start. So far I have 1) checked fuel is flowing from fuel tank to carb ok, 2) adjusted mixtures (1st time plug was coated in black soot), 3) jury rigged alternate fuel supply striaght to carb cutting out fuel tank issues, 4) still got spark at plug, 5) about to try new carb, but not confidant this is it.

Does anyone have any other ideas? Engine turns over ok, and does not appear to be overheating - no idea where to go next, except condenser and coils possibly? Thanks for reading.
 
In my hunt for a boat I came across several with Vire engines and after doing some research the symptoms you describe are apparently very common

I'm slightly put off by the "doesn't appear to be overheating" but the received wisdom is that the cooling passages become clogged up over the years preventing proper cooling of the entire engine thus bits get hot and the engine dies once it's warmed up

It is, apparently, next to impossible to do anything about it if the above is the case.
 
It may not be connected, but a friend had a Vire which sometimes exhibited similar symptoms. One thing it didn't like to do was drop to tickover and then open up again - not good when approaching a pontoon, or in our case a lock gate! After replacing the engine he discovered that the carburettor, which is aluminium, has a bleed hole to allow unwanted fuel to escape, it had grown closed due to salt atmosphere. This is needed because the fuel is pumped by a diaphragm driven by crankcase pressure pulses, so tends to flood on the overrun. If you check out this bleed, it can be cleared (gently) with a very small drill and may just cure the running problem.

Rob.
 
Hello fellow Vire engine sufferer :D
I've just had very similar symptoms on my Vire 7, like you I tried several things to keep it running for longer than 15-20 minutes.
In the end I have replaced the rubber pump diaphragm, top screen filter and float valve as well as giving the carb a thorough clean down and all new gaskets.
Cost of carb repair kit is (I think) about £45. Engine now runs sweet as a nut and keeps running with far more power - or so it seems, than before.
This website has a lot of valuable info that will help keep your engine going.

http://gofree.indigo.ie/~vire7/

These are really simple engines and nothing is beyond a resourceful owner - including de- gunging the cylinder water jacket, the hardest part of that job was getting the black mess out of the pores in my skin :)
PM me if you need any further info.
 
The overheating suggestion is easy to check. I had a 2-stroke motorbike that used to seize due to overheating. The engine would lock solidly for 10 minutes, then free and run perfectly well.

I have known something similar with a car when the coil was faulty but you say the spark is OK, so sorry, no more ideas.
 
TRidge said:
I have an old Vire 2 Stroke in an equally old sail boat. Its a single cylinder, 6hp, which now has the habit of starting quite easily, and running well, but after approx 15 mins stops with no warning, and will not re-start. So far I have 1) checked fuel is flowing from fuel tank to carb ok, 2) adjusted mixtures (1st time plug was coated in black soot), 3) jury rigged alternate fuel supply striaght to carb cutting out fuel tank issues, 4) still got spark at plug, 5) about to try new carb, but not confidant this is it.

Does anyone have any other ideas? Engine turns over ok, and does not appear to be overheating - no idea where to go next, except condenser and coils possibly? Thanks for reading.
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May I suggest that you check the tank air vent. If that is blocked a vacuum will build up in the tank as the engine runs until a point is reached where the engine gets starved of fuel. Then if you leave it until the vacuum goes, it will restart again, only to repeat the cycle.
 
I have seen exactly similar problems in car engines. The cause was always a faulty coil, which was complete until it got hot and then went open circuit due to a break in the windings.

I appreciate that you may have a Dynastart or similar, but when it happens again check for continuity
 
Thanks all for suggestions - do not think engine is overheating and seizing cos will still turn over, but not fire up, after it stops running. Carb - maybe, will find out when I fit a new carb - after that will check coil / condenser, but I am still getting a spark at the plug after engine stops, tho' might not be right sort of spark - will let you know
 
Not the carb - new carb fitted but exactly same problem persists. Did notice on turning engine over by hand, no spark, needs Dynastart turning it over to produce spark, so may be weak or intermittant spark, trying to get hold of colis and condenser now.
 
It's always a good idea to try a NEW spark plug when having problems with a petrol 2-stroke, particularly one that's using a petroil mix. Make sure you have an appropriate one available, I had a lot of trouble trying to find one for a '60 villiers engine a few years ago simply because most modern ones were designed for a higher temperature range.
 
Thanks again for comments - fitted a new spark plug, plugs actually, made no difference. Ref fuel tank, I rigged up alternate fuel supply direct from open vented bottle straight into carb by 3 ft petrol pipe, bottle suspended 2 ft over engine (dodgy I know) - same result, died after 10 to 12 mins. Also did check for fuel coming out of pipe when stopped - fuel still flowing. Next up, coil and condenser.
 
Ah, the condenser. Solved a couple of petrol probs by changing that. Difficult to test, so best just try a fresh one. Almost any one you can find, that fits, will do.
A
 
Sucess (I think) - replaced HT coil and condenser, engine now running 50 mins + and all seems fine. 4 day trip coming up will prove it. Thanks to all suggestions, and to Nick Le Feuvre (see http://www.vire6.info/) for his help with parts and advise.
 
TRidge said:
Not the carb - new carb fitted but exactly same problem persists. Did notice on turning engine over by hand, no spark, needs Dynastart turning it over to produce spark, so may be weak or intermittant spark, trying to get hold of colis and condenser now.
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The prob with old Villiers engines and such like is that the magnetism goes weak in the flywheel when it warms up and the sparks fail. Suspect it could be something similar here.
Stu
 
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