89 15 hp evinrude dies at high revs after a few minutes

mardom61

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Joined
Aug 3, 2009
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This is my first post, although I have been reading alot on this website. Here is my problem. I bought a 1989 evinrude 15h.p. short shaft from my friend. A few years ago he said it did not work well and had someone rebuild the carb but that did not help. I have since bought the motor and it has been sitting for about 3 years.

When I first started it with fresh 50:1 mix gas it would die as soon as I hit the throttle. I took the carb apart and discovered that the plastic tube was in pieces and there was also missing the clip that attaches the needle to the float (sorry I do not know all the correct part names). I ordered a carb rebuild kit and completely cleaned the carb with carb cleaner, compressed air etc. I reassembled and adjusted the slow speed needle 1 1/2 turns out from being lightly seated, as per many recommendations I read on this site.

I also installed new plugs, Champion QL77JC4, same that were in it before and gapped at .030". I also took the fuel pump off to make sure that the screen was not clogged, no probelm with fuel passing through.

Put the muffs on, open the vent on the tank, prime and engage the choke. After a few pulls it starts. I fine adjust the slow speed and it idles nice, revs freely to about half throttle. The problem occurs at higher throttle, above the half way point. It runs good then suddendly dies, not sneeezing but more like you pulled the boots off both plugs.

It will start again after a minute or so and needs to be choked. Did some more research and read that Champion L77JC4 are best again gapped at .030", so I tried that as well. Put a bit dilectric grease on the on both boots of the wire. Seems to run a bit longer now, but the same condition exists. I should mention that both plugs have color to them so they should both be firing at some point.

After looking over a few things I noticed that the primer bulb from the tank had a small crack and there were O rings missing at the fittings. replaced the primer bulb and ran the motor making sure the buld was sending fuel to the motor, same deal, motor dies after a few minutes.

I know this is long, almost done. There is water coming out of the pee hole and right after the motor cuts out, I have no problems putting my hands directly on the head, it does not appear to be over heating.

I did try pulling the boot off the plugs while running at idle, when I took the top on off it ran,the bottom it died. Now I am thinking I have a coil that is about to go or a power pack issue. Any help trouble shooting this thing would be great.

Martin
 

Rick.

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Joined
Jul 30, 2006
Messages
3,740
Re: 89 15 hp evinrude dies at high revs after a few minutes

Sounds like two problems to me. First, your top isn't getting spark. Probably the coil but if you like you can change them out and see if the no spark follows that coil. Prior to that you can switch the plugs to prove they are good. Next thing is your fuel pump. At full RPM it could be your not getting enough gas to keep her running. Pumping the bulb will tell you if it is your fuel pump as pumping the bulb will overcome a weak fuel pump. One thing you should do, if you aren't already, is get your tank up off the floor. I sit mine on a stool so the pump doesn't have to lift the fuel so far. Another thing you should be aware of is you should not rev your engine unless it is in the lake. It has no work to do otherwise and can be damaging to it. Best of luck. Let us know how it goes. Rick.
 

mardom61

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Joined
Aug 3, 2009
Messages
10
Re: 89 15 hp evinrude dies at high revs after a few minutes

Thanks Rick, I will try the coil. My tank is in the boat beside the engine so it does not have to travel high up. I did try to pump the bulb when it starts to die, that does not help.

I will let you know how it turns out, thanks again.

Martin
 

Rick.

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Joined
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Messages
3,740
Re: 89 15 hp evinrude dies at high revs after a few minutes

Martin: That is strange as usually it will run fine with only on plug getting spark. It will however lack power and won't get up to speed but in my experience, it won't just up and quit. Rick.
 

addy27

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Aug 3, 2009
Messages
3
Re: 89 15 hp evinrude dies at high revs after a few minutes

Wow I just found this site and I have a very similar issue with my johnson seahorse. It's a 1982, 7.5hp. Initially it was running perfect at idle, I could troll for hours but as soon as I give it gas it would want to cut out. It wasn't cutting out completely at first it would choke like it wanted too. Now it won't run for long at all then cut out. Gas flow into motor all good. New plugs gapped properly. Still won't run right. One thing I noticed was that the single wire coming from the coil was arcing out at the bolt it was attached to. This can't be right. Could it be the source of my problem? I ask because I know very little about this.
 

Rick.

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Jul 30, 2006
Messages
3,740
Re: 89 15 hp evinrude dies at high revs after a few minutes

addy27: Welcome to Iboats. It is a great site for sure. You just tapped into an others thread which is a no no on the forum. Start a post of your own and you will be helped. Make sure to put the year, Hp. and a brief description of your problem in the title. There are some Top Guns here that will give you very good information but you have to play by the rules. Best of luck. Rick.
 

mardom61

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Joined
Aug 3, 2009
Messages
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Re: 89 15 hp evinrude dies at high revs after a few minutes

yesterday I received my parts from iboats. I decided to order 2 coils since they are relatively inexpensive and likely that the second one would likely go soon with my luck. I also replaced the fuel pump. The motor started the second pull and idled really nice. I will probably test it in the lake tomorrow night. Hope that did the trick. I will update with the results.
 

mardom61

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Joined
Aug 3, 2009
Messages
10
Re: 89 15 hp evinrude dies at high revs after a few minutes

Just got back from a test run at the lake. Runs good, I will need to fine tune the slow speed but other than that I'm very happy. I ran it for about 25 minutes total, gets on plane just fine and has the power that it should. Rick, thanks for your help, very appreciated.

Martin
 

Rick.

Captain
Joined
Jul 30, 2006
Messages
3,740
Re: 89 15 hp evinrude dies at high revs after a few minutes

So glad to hear your back up and enjoying your engine. All the best. Rick.
 
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