1988 Evinrude 140 vro - missing at idle

[lexer440]

Compression is good, fuel system is good and clean, carbs stripped, cleaned and blown with c/air and new kits in. coils are all good, plugs are new. Reeds are all good. motor runs great flat out.

At idle it misses and quits, restarts ok, primer bulb stays hard, giving more gas does nothing. Plug inspection shows 3 plugs good one is wet and fouled although not badly, guess this is the misser.

I have a manual but am at the limit of my knowledge, suggestions please?

also, looking at motor from the rear with the plugs facing me, which is the number one, just to confirm as the manual does not actually identify it.

 

[oldcatamount]

Re: 1988 Evinrude 140 vro - missing at idle

Could that one plug that is wet and fouled, be gapped wrong? Maybe you could check that plug wire for a break or chaffing. Do a compression test to see if your numbers are close. Seems like it should idle even it has a weak cylinder, however it would idle rough though.

 

[lexer440]

Re: 1988 Evinrude 140 vro - missing at idle

Well,.. thanks for the thoughts. Plug gaps are good at .30 and i did replace that cylinders plug lead with no difference. I will redo compression test and work my way thru sync & link and tune up sequence with extra care.

As an afterthought, the idle jets were #41 as they were supposed to be. the intermediate jets were also #41's and the book said they should be #54's. I replaced the i/mediates with #54's and medium running speed improved greatly. Is there a reason why they would have been 41's and could that be related to my troubles?