Need Help!! 90 HP Evinrude 2 Stroke Idle Issues

[windknotnc]

I have a 1998 90HP Evinrude on my skiff that I cannot seem to track down an idle/ starting problem. Model is E90TSLECM. I have removed carbs, soaked overnight, put new kits in them except for the knockout plugs. I am running new gas, have checked the fuel pump to insure no diaphragm perforations, new fuel lines, new separator, new fuel filter and new plugs. The engine is very hard to start and sputters when cranked and I have to continually push the primer to keep it running. If I can ever keep it cranked long enough to rev the engine it usually is ok. It takes the fuel well and runs great at 2500 rpm and higher. When coming from WOT back to idle it is ok to start with but gradually starts sputtering and dies. Then the same cranking process starts over again. I have checked the primer solenoid and it is functioning correctly. When cranked on the cup and does idle the rpm is about 1150. This seems about 300 rpm too high out of the water. Does anyone have any suggestions as to what the problem could be? What have I missed?

 

[DaleH]

First off, all OMC plugs should be gapped at 0.028" REGARDLESS of what documentation you may have to the contrary. Also use the RIGHT plug and new plugs. Sounds like you need a 'sync & lync' adjustment.

Also when starting, prime bulb hard, turn key ON but not to crank, push IN on key and count to 6 slowly, then release the pushing in on the key ... the re-prime bulb and turn to crank. That should set the EZ Start or Quick-Start feature, which automatically advance the timing to warm her up.

This post here tells how to tune an OMC V6 but the process is the same. DO THIS IN the water ... NEVER tune an OB using muffs!

www.classicparker.com/phpBB3/viewtopic. ... ne+up+carb

 

[windknotnc]

Dale, what about to passages behind the knockout plugs? Any experience with these causing idle problems

 

[BradH]

I was told by an old OMC mechanic that these V4s idle much better if tilted up a little past level.

Years ago I ran a 90 premix on a Whaler for a guy I was working for and had a horrible idle and would cut out when shifted. Started tilting up when off plane and 90% of problems went away.

 

[DaleH]

Also make sure that the manual choke lever (red) is CLOSED!