Yamaha Prime Start

[horry]

I have just replaced the prime start diaphragm on my 1996 Yamaha 90hp (600 hrs) for the second time in 40 hours. Fuel has always been cleaned through CAV filter (new) and as such, no water present past filter and carby bowls showing no signs of sediment. Is there perhaps a probable cause for this continuing failure?

 

[rodbolt]

Re: Yamaha Prime Start

hello<br /> are you using any type of fuel additives? I am not sure of the blends of fuel in the land of Oz. I will try to think to look at the passage to see if it connects to the crankcase. has the engine had any lean sneezing ? <br /> good luck and keep posting

 

[horry]

Re: Yamaha Prime Start

Thanks for the quick reply Rodbolt. I don't use an additive in fuel. Certainly the first time the diaphragm failed there was quite a large backfire as fuel in the main tank ran out (and before I'd switched to the secondary). I reckon that for that failure we could lay that sneeze to blame. Didn't here one this time though - perhaps an idea to enrich the mixture a little (1/4 turn) and see what happens.