Evinrude 120 stahls

[kryptonite850]

Hi guys. I've been working the bugs out of my 1988 Evinrude 120. I got to a point where it was backfiring and running rough whether on the water or on the ears, so I took it to the mechanic as I couldn't decide whether it was fuel or ignition.

The mechanic adjusted the floats on the carbs, new plugs, set the idle down, made sure all carb jets were open, checked the ignition box for shorts, checked compression, checked spark. He got her running smooth and I went to pick her up.

I ran her on the muffs and she purred like a kitten. WOW! I decided to do a water test before dragging it all of the way up to Lake Erie for fishing. I put her in a local body of water, she fired right up and purred like a kitten. I began running it around and she didn't miss a beat until about 5 minutes in. She just flat died. Just like shutting the key off. No coughing or sputtering, just gone. I started her up and she sputtered til she died. I let her sit for about 10 minutes and she fired up and purred like a kitten. She ran fine for about 5 minutes and then flat died again with no sputtering or coughing. She started up right away, but coughed and sputtered til she died. I let her sit for ten minutes and she fired up and purred like a kitten. I repeated this process several times.

One cylinder was having known issues when I took it to the mechanic (carbon build up on a plug). I told the mechanic of this. So, when I got it out of the water, I pulled all four plugs. Three looked a little dirty, but were wet and not really suspect. That fourth plug (originally suspect) was dry and coated with carbon build up.

Even with the boat sitting for 20 minutes before pulling the cover off of it, the block was too hot to lay your hand on for more than 3-4 seconds. It was pumping water fine the whole time while on the water.

Any ideas what might be going with this motor?

 

[Daviet]

Re: Evinrude 120 stahls

Does your overheat horn work?
You might check the spark when it stalls, sometimes an ignition componet will fail when hot and work again when it cools off.

 

[kryptonite850]

Re: Evinrude 120 stahls

Does your overheat horn work?
You might check the spark when it stalls, sometimes an ignition componet will fail when hot and work again when it cools off.

Your first idea was something I was mulling over in my head (ignition component failing from heat). I'll have to check on the overheat horn. The engine overheating would make sense for all of the symptoms i would think. Since it flat dies, I suspect thats the engine protecting itself from damage? The rough running til it sits a bit kinda makes sense.

 

[kryptonite850]

Re: Evinrude 120 stahls

UPDATE: I took it back to the shop. The guy there ran some diagnostics and said that he was pretty sure it was the stator, but could also be the powerpack. I had him replace the stator. This cleared up the slight popping that it picked up last time out.

I took it for a test ride and ^(#(@! the dirty (#*#! stalled out again about five minutes in. I'm cussing because that's over $800 in fixes that I have in the motor so far and it's stalling on me. So, through the cussing, I fire it back up and it's running like crap. I push the key in for choke, out of desperation to keep it from stalling and the engine catches and she revs slightly. It burns off the choked fuel and starts idling like crap again, so I choke it again and it takes off again til that fuel is gone. I decide "f-it". I hit the choke for a good three seconds while she is still running and then punch the throttle. First, let me tell you, this was a HELL OF A HOLE SHOT! I took off like I had just stuck my best asset in the campfire. I backed her down to about 3000rpms and proceed to cruise around at a solid 3000 rpm for 20 minutes or better. This is the longest and best the damn thing has run since ever.

I put her in neutral and she purred like a kitten, idling at about 600rpm. I let this go on for about 3 minutes. I then slowly progressed up the throttle back up to 3000rpm and she sailed right along for another 10 minutes with no issues. I slowed her down to 2500 for a few, then 2000 for a few. At 2000 rpm she ran fine, but I thought I heard the engine change tones twice in about 10 minutes.

I decided that maybe there was something that had been plugged up or gummed and it had blown out, so I proceeded to play with the boat as any red blooded American guy would. After all, I've owned this boat for 2 months and have yet to get to really play with it. So, I have fun doing hole-shots and just cruising around for another 20 minutes or so and she runs like a top the whole time.

I decided to try to see if this is a temperature/choke issue, so I took her to shore and shut her down for a good 20 minutes. Time was running short or I would have waited at least an hour. Especially since I had something to eat while at shore. But, after 20 minutes, I fired her up and we went right out. I took her up to 2000 rpms and ran her for 3 minutes or so at that. Ran fine. Took her up to 3000rpms and she ran fine like that for a good 10 minutes.

It was time to call it an evening, so I took her to shore and we had to monkey with getting it on to the trailer with no dock (sandy beach launch). It idle at 500-600rpms just fine and was in and out of gear at very low rpms several times while lining it up with the trailer. No issues during this process.

Any ideas as to why after that choked-up hole-shot it cleared up? Am I likely to see this issue arise again the next time that I take it out?

 

[boobie]

Re: Evinrude 120 stahls

Try it again and let us know what happens. You still may have a problem.