yamaha 4ac 2stroke problem

[fishaholic]

hi all.
i have a 4hp langshaft yamaha givin me hassle.
started when it cut out and wouldnt start again for me last wknd.
when i got it home i found that the problem was due to a wet spark plug?
I decided to change the plug and clean carb out also.
When i took it out this weeknd it went fine on full throttle for about 500yrds bfore cutting out.
when rowed back to the jetti i was able to start and run it in neutral. But it wouldnt run for more than 10/20 seconds also while i was doing this i noticed that no water was dripping from the tell tale hole underneath the engine.

does anyone know why the inside of the sparg plug could get wet?

should water be running out from the telll tale hole when the engine is in neutral? ie could the engine b overheating and thus cutting out after full throttle for 20 seconds?

[mitch]

spark plug wet with what ? fuel or water ?

what is the fuel pump like any leaks in diaphram if it is fuel that is making the plug wet.

is tell tale tube blocked

[fishaholic]

there was no smell of fuel off the plug plus the fluid didnnt evaporate off the plug after 1 hour so i assume it was water.
the plug was screwed in very tight so i dont think water could have got at it from the outside.
dont know if the hole is blocked. but should water be flowing through from it when the engine is in neutral? im on the verge of ordering a water pump repair kit for it.
oh yeah sorry i didnt read your reply properly! the diaphragm in carburetor is not in good nic. just ordered a carb repair kit for it.

[boats.net]

Need to check compression to see have a blown head gasket.

[fishaholic]

i took the liberty of buying the manual for my engine and have to say it was 40 euro well spent! reading it was like being back in primary school! took the engine and manual to a mechanic friend of mine and after lookin at plugg he said definitely fuel caused by bad diaphragm! as for why it was cutting out after 500yrds on full throttle was my fault. opoened the water pump and found an impeller with all blades broken into tiny pieces. after reading the manual i found out why! turns out that just starting the engine without being immersed in water can completely destroy the impellor. when i cleaned out the carb at home i hadnt got a tank so i swithched it on for just bout 20 seconds a number of times just to see how it was running!
so have ordered carb repair kit and new impeller and hopefully i havnt done any more damage to it? just wish i had've bought that repair manual sooner!