Yamaha 8hp twostroke

[Grant S]

My 8hp was running fine when put away a couple of weeks ago and now it starts fine on the choke and dies when the choke is put in after warm up. <br /><br />If I pull the choke out halfway it will keep running for a while and start to die, I then rapidly pull the choke in and out and it keeps running and then dies once I stop. <br /><br />It starts up again on the choke straight away and repeats the symptoms again. Fuel related I think, I've had the carb off and blown it out , no obvious gunk in it and the problem is still there once the carb is refitted.<br /><br /> Fuel is getting to the fuelpump. I tested the diaphragm by putting it over the end of a flashlight and no pinholes are visible.<br /><br />The fuel is two weeks old.<br /><br />What next?

 

[WillyBWright]

Re: Yamaha 8hp twostroke

I recall a co-worker working on one of those carbs and he was having the same symptoms. I believe there was a rubber plug (near the float) missing or in the wrong place.

 

[rodbolt]

Re: Yamaha 8hp twostroke

hello<br /> time to open up the carb again. and test your tank for trash/water. by cycling the choke you force the engine rich. sounds like something is clogging a jet someplace.

 

[Grant S]

Re: Yamaha 8hp twostroke

When looking at the carb throat from the choke end there is a hole of a bit more than an eighth of an inch diameter at the top. I get no air through that one but wonder if it is just a drilled hole that has been blocked off. All other orifices pass air.<br /><br />I'll strip it again and have another look. fortunately it is quick to do.