1987 4.3 Merc misses after 3000 rpm

[Evinrude Boater]

First time out after dewinterization. It started immediately after filling the float bowl and idled nicely. Didn't notice anything until after 3,000 rpm when it began to miss slightly and intermittently. It didn't get past 4,000 rpm either. All the plugs look good, the fuel had stabilizer, the oil looks good, new water separator and the carb was rebuilt last year. I haven't checked the fuel filter though. Not sure if I should just run the old gas out of it and fill with new before looking elsewhere for a problem.

 

[HT32BSX115]

Re: 1987 4.3 Merc misses after 3000 rpm

I haven't checked the fuel filter though.

Howdy,


Well that's pretty important!

You also might want to check fuel delivery from the tank since it appears to be a fuel delivery problem.


Sometimes the pick-up screen is plugged, anti-siphon valve is sticky or the filter is plugged. If the filter is plugged then the anti-siphon valve WILL frequently have debris in it. Start at the tank and work towards the engine. At some point you'll need to consider the fuel pump too.


regards,


Rick

 

[Evinrude Boater]

Re: 1987 4.3 Merc misses after 3000 rpm

Seems a good run has got the bugs out of it. It's pullin' 4800 rpms with a sweet sound. I'll still check the fuel filter since I failed to do it when winterizing.