Runs great but erradic!

[JOHN12]

20 hp merc #561---,
Finally got her on the lake after all the work/problems.

When running mid throttle it will rpm will go up and down and one time quit completely but started again on first pull.

Fuel pump (it is a diaphram), I did replace all the pump gaskets but did not have a new diaphram, however did not see any tears etc in it.

Also rebuilt the cars, new switch box/ charging coils.

Nver went "full" throttle as it is on a small aluminum boat and had my boy with me, too much for that size boat.

Any ideas??

Thanks
John12

 

[Laddies]

Re: Runs great but erradic!

John, it sounds like a fuel pump problem get a kit with the ck valves in it and everthing should be fine. Your right on a 14' boat that engine is definitely a two hander

 

[JOHN12]

Re: Runs great but erradic!

Laddies;

Thanks again for all your help!

I did not see any check valves/ballls in the diaphram pump when I put in new gaskets.
Is there an aftermarket pump kit with these?

Thanks
John

 

[Laddies]

Re: Runs great but erradic!

I don't think any aftermarket kits come with ck valves so you need to get one from merc