Cutting out

[veilside180sx]

I have a 1970 Fastwin 18 hp.

The motor is sputtering/cutting out during partial throttle. It runs great at idle and decent at full throttle.

Carb was rebuilt last year by a reputable shop, new gear stacks in the lower unit (irrelevant), waterpump (irrelevant), plugs were changed last week (did help a little).

Motor has ran great ever since the carb was rebuilt, but has just recently started to act up like this. Changing the plugs (Champion J4C) did help idle and WOT, but didn't fix the cutting out issue.

Any ideas?

 

[tashasdaddy]

Re: Cutting out

plugs gapped at .030, have you check point, for being clean?

http://forums.iboats.com/showthread.php?t=299680

 

[lindy46]

Re: Cutting out

If you have good spark, then check your fuel pump. My '72 18hp did the same thing. Would sputter at mid-throttle, and sound like it was going to die. Never did strand me. But I had new coils and tune-up and good spark. Finally traced it to the fuel pump starting to go.

 

[veilside180sx]

Re: Cutting out

plugs gapped at .030, have you check point, for being clean?

http://forums.iboats.com/showthread.php?t=299680

Plugs are gapped at .030, but I haven't cleaned the points yet. I figured that would be next on my agenda.

If that doesn't help, then it's on to checking the fuel pump I guess.

Thanks for all the help so far.

 

[Knightgang]

Re: Cutting out

While you are looking, check your manual and do a resistance test on you plug wires. I had a problem once with cuttin gout like this and it turned out to be a conductor in a plug wire cap. It is worth a shot and a cheap fix if that is the problem. The manual should tell you what the restiance numbers should be and how to conduct the test...

 

[kbait]

Re: Cutting out

Search for link/sync. You want the throttle valve to begin opening exactly where indicated on the armature plate cam (probably not correct term, but you'll see when you search it out).