misfires then clears at WOT

[pudlejumper]

i have a 1990 140 V4 evinrude that starts up everytime,but she doesnt idle so smooth,and when i gun it she misfires only untill shortly after i plane out then it goes all out like a top.<br />i have a maual but the year and model range is crazy.im just basically looking for ideas where to start like does that sould like a fuel problem or ignition? the plugs are good and just in case i cleaned them up spotless.<br />oh and with more of a load (more people in the boat) it wont clear up and just continues to misfire.if you need anymore info let me know please.

 

[russeller]

Re: misfires then clears at WOT

i have a 66 rude 40 hp and i have the same problem maybe we can kill to birds with one stone

 

[Walker]

Re: misfires then clears at WOT

Sounds like a fuel problem to me. I'd start with a good carb cleaning and overhaul.

 

[REELSPORT]

Re: misfires then clears at WOT

Like walker said start with the carbs and then the fuel delivery system fuel pump gas lines fuel filter. sounds as if you are getting some air from somewhere.

 

[pudlejumper]

Re: misfires then clears at WOT

update:<br />im gunna work on the carbs tomorrow (day off) but i have a better symptom, its RIGHT after 3,000 rpm that it clears up doesnt have to be WOT.it putts till 3,000 then after that runs perfect.<br />does the low on the carbs switch to high side at 3,000?

 

[pudlejumper]

Re: misfires then clears at WOT

nuther update:<br />ok took a look at the carbs and i dont have needle valves it looks like its a 1991.injected?<br />it looks like two jets on the left side of each carb and just so happens the top left carb is spurting gas out of the bottom jet and the hole in the bottom which im guessing is overflow,so ta da stuck float huh?sorry if i dont know what im talking about at all,im use to cars.

 

[Solittle]

Re: misfires then clears at WOT

Follow the shop manual for the rebuild. They know what they are talking about.

 

[pudlejumper]

Re: misfires then clears at WOT

yet again:<br />ok today i rebuild the suspicious carb,put it all back together and its doing the same thing with sputting the gas out of the bottom (air bleeder i believe the book calls them?) when i had it apart i noticed the top one had a gold fitting on the back side where as the bottom one did not. also when idleing the carb i seem to be having a problem with has some serious air sucktion where the other three hardly has any. PS i sat the float perfectly on this carb so thats obviously not my problem.<br />and also when controlling the throttle from the engine i noticed a delay there much more,could this just be the timing and im pokeing around the wrong thing? either way id like to stop the fual leakage problem.

 

[pudlejumper]

Re: misfires then clears at WOT

timing is everything.really.<br />umm still spitting out a bit of fuel but its not as bad at all and now she runs good at any RPM.

 

[pudlejumper]

Re: misfires then clears at WOT

ok i got too excited when she was running really good,turns out it wasent the timing,i just happen to re-adjust that at the same time i semi cleaned the reed valves. as i stated earlier im getting blow back from my top right carb. if i take the carb off and spray the reed valves it does pretty good when i gun it the first time then after that she is back to her old self.would a bent/warped/not closing all the way reed valve make it run bad under a load?

 

[pudlejumper]

Re: misfires then clears at WOT

*pulls hair out*<br />ooooooooooooooook heres a horrible update for ya,i found my problem with my carb blowing it was a broken reed block gasket.i replaced that put everything back on and now it wont even run.it tries but i cant even keep it running for more than 5 seconds.ONE time it cleared out then idled for 3 seconds the sputtered then died.the other times i actually got it to start it sounded as if it was running on two cylinders.<br />i keep trying to think of things i could have done wrong but i put everything back.all new gaskets.the only thing i can think that i didnt know if i set it up how it was was the throttle linkage,would that DRASTICALLY effect my timing?

 

[fireman57]

Re: misfires then clears at WOT

Use your manual and do a link and sync. you can also check for spark while someone cranks it for you.