73' Evinrude 25 hp - Intermittent miss

mchin

Petty Officer 2nd Class
Joined
Jun 15, 2007
Messages
195
I have this motor and it was running like a charm, but now I'm getting this miss, at all speeds. The miss is not happening with any regularity or pattern, but it does happen from idle to WOT, but not all the time. My carb is clean and just re-built, I have the right plugs, my gas is fresh, I've de-carbed, replaced the coils and ignition parts, and like I said it was running great. Am I missing anything? I suspect it's the condensers, anyone know the tell tale signs that your condensers are going? I'll probably replace it all again, double checking my wires for ignition shorting. I just hate not knowing.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 73' Evinrude 25 hp - Intermittent miss

possible spark plug wire arcing to the block. or the case cover lock.
 

mchin

Petty Officer 2nd Class
Joined
Jun 15, 2007
Messages
195
Re: 73' Evinrude 25 hp - Intermittent miss

I thought of that too and moved the wires clear of the cover lock. But you are right, I might be shorting some where. I ran the motor without the cover and still the miss. The motor is always able to run through it, but you can feel the shudder. Do you think I'll see a short if I run the engine in complete darkness? Both spark plugs are lighting up great.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: 73' Evinrude 25 hp - Intermittent miss

Yes, run it in the dark and use a spray bottle of water to mist the wires. If they're arcing, you'll see it!
 
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