clint
Petty Officer 2nd Class
- Joined
- Jul 11, 2006
- Messages
- 157
8) My 140 Evinrude is finally is back to normal at 5500 rpm's. Here is what I found out today after test run. It took off fast and planned out beautifully, went right up to 5500. I dropped it down to 4500 and ran it light and steady. Only problem was when I throttled back down I felt engine miss a low rpm and idle? Took off again and it planned out to 4500-5500 and ran it at 4500 for about an hour. Ran it again at low rpm and it was missing again. Then it just wouldnt go over 3000. It was locked at 2500-3000 rpm's and that was it again. Back to the drawing board. The last few minutes to the ramp to take the boat out of the water, my son & I were netting the last of the blue claw crabs with a net off the high tide mark and I put my hand on the cowl cover which was wet and damp from the run and I felt a jolt, shock? When I got boat home, I found bottom spark plug wire boot was indented, cut thru from the cowl cover inside bolt from the lock down lever, grounding out #4 cylinder which was missing in the past and not going over 2500-3000 rpm's. But it never missed or didnt fire with cowl cover off in test tank or with muffs. Cover was off and engine not too hot when tested. I assume today and in the past when engine got to operating temperture the rubber got soft on the spark plug boot and grounded out to the bolt. The bottom of cowl cover has rubber boots on the three points front and the 2 in the rear which on the #4 cylinder side it was ripped up and made a good ground right to bottom of cover and directly to the engine ground. Also what makes it worse is my cowl cover seal needs replacement also which I lose that extra clearance. So the mystery is solved after I changed spark plugs, spark plug wires, I re-built the carbs, replaced fuel pump, changed the head gasket and cleaned all my ground leads. I want to thank all of you for writing back to me and helping me pinpoint what was going on. Thanks so much to all the pros on this site! 
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