Evinrude 1990 90hp V4 on VRO running problems

[titch]

Hello to all. My evinrude 90hp will run fine on muffs but not in the water. Idle is fine and will throttle up out of gear fine, but as soon as i put it in gear it becomes a little lumpy when i try to open the throttle it wants to stall and have to take it up slowly. I took the prop off (to see it the prop was causing the problem) and retried it in the water and the engine went through the revs with no problems. Put it back on muffs and the engine was fine even tried it in gear and it reved up fine but not full as didnt want to have a runnaway engine.

History,
carbs have been stripped and cleaned
link and sinqed
timed,
plugs and wires are new and good
compession is good on all 4
Continuity on coils is good
power pack tested seems to be at book recomendation
no leaks on the fuel oil side that can be seen.

Has any one had this problem before and if so can the give any recomendations

THANKS

 

[tashasdaddy]

Re: Evinrude 1990 90hp V4 on VRO running problems

idle speed. when you set idle speed on muffs, you have no back pressure on the exhaust system. you have to set the idle 2-300 rpms faster, to account for this. then the motor will start in the water. you then have to place the motor in gear, and fine tune the idle, so it stay running in gear.

 

[titch]

Re: Evinrude 1990 90hp V4 on VRO running problems

Thanks for the reply tashasdaddy. the engine it tuned in the water and runs at idle but the engine jumps a little. when i open the throttle it wants to die before reving up, but when i take the prop off and rev up it goes through the revs no problems at all. It has no problems out of the water at all in or out of gear so i think it rules out a prop problem (am i right?)

Would it be a fuel pump problem or something to do with the back pressure??

Thanks again