Yamaha 250 saltwater series losing cylinders

[MCook]

I have a 94 Yamaha V76 250 Saltwater series (txrs) that is losing cylinder 1 & 3. No fuel obstruction, have replaced plugs, fuel filters, coils, rebuilt carb and replaced starboard head gasket.<br /><br />Any Ideas?

 

[dkondelik]

Re: Yamaha 250 saltwater series losing cylinders

can you confirm that you have, or are loosing spark (on the muffs or in a tank)when you loose 1 & 3?<br /><br />is it fading once warmed up? if yes, maybe electrical. some electronics, once old and week or having been stressed, kind of "quit" once they warm up and then pretend that they are better once they cool down.<br /><br />let us know what you find

 

[MCook]

Re: Yamaha 250 saltwater series losing cylinders

Let me add to this.<br />105 lbs compression in 1,2,3,& 4 cyls. Has spark when cold or hot, but I am not positive how strong it is. Also it would pick up the 1 & 3 cylinders when given ull throttle. The problem seemed to get worse and worse until now it won't pick them up at all. <br />I have switched the coils around to no avail.<br />Thanks, Mark