1990 90hp evinrude rough idle

[djeffery]

I cleaned the carbs on this motor new champion plugs .030 gap, wires good, 2 new and 2 old coils,<br />compresion is 95-110psi, I replaced the roller cam for the timing advance in which the outer layer had ripped off, as a result I could not get a good idle out of it. Now I can get a high idle but it sputters and stops abruptly sometimes at idle, its fine at mid and wot any help would be much appreciated as this motor is driving me nuts, not much fun docking when you cant idle!!!

 

[andy6374]

Re: 1990 90hp evinrude rough idle

Sounds like its running a bit lean. Are you sure the throttle plates (butterfiles) in the carb throats are fully closed at idle? The must be for a good idle!<br /><br />If this checks out. I think its time for a carb cleaning.

 

[Silvertip]

Re: 1990 90hp evinrude rough idle

Many folks say they "cleaned" the carbs but all they really do is clean the float bowl. Carb cleaning consists of total disassembly, soak in carb cleaner, blow out all internal passages with compressed air and reassemble with new kits being careful to set float level to spec. Then do a link&sync after installation on the engine. Idle mixture and idle speed must be set with the boat in the water. Rough setting on muffs gets you in the ballpark but final adjustments must be made in the water due to added back pressure.

 

[djeffery]

Re: 1990 90hp evinrude rough idle

I didn't soak the carbs as they where clean inside but I disassembled them and used compressed air to blow out all passages and made sure I could see through them do you think the other coils might be bad?<br />P.S. thx for the help guys!!!

 

[Wakeboarder Tom]

Re: 1990 90hp evinrude rough idle

Guys<br />Not sure if this helps, but I have been advised in the UK that fuel only lasts a month before it starts to lose the octane. We had a serious problem with cutting out at idle and misfiring at low revs at the beginning of last season before we found this out.<br /><br />Or maybe it's just cheap limey fuel that's a problem!!<br /><br />When I say cheap - the damn stuff is now at £4.50 a gallon - nearly $8