bad coil suspected

[RustynHouston]

Similar to: http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=036753#000002 <br /><br />On 115 Hp Evinrude 1977, I suspect a bad coil(s). Or perhaps power pack?<br /><br />Running at set throttle (engine seems sluggish) - all of a sudden she takes off "like a bat out of hell!" She scares me so I pull the throttle back down and she's sluggish again.<br /><br />I took off all the coils and found the insulation to be melted on one only. <br /><br />Would one bad coil cause this? Or should I replace all 4 coils AND the powerpack just to make sure?<br /><br />Alocal repair shop charges $265 plus parts to go through the entire engine. All 4 coils ($29 ea) plus 1 powerpack at $90 is less than labor of the shop. <br /><br />Do you smell what I'm stepping in?

 

[Barnacle_Bill]

Re: bad coil suspected

I would replace that one coil and then go from there. It may solve your problems.

 

[RustynHouston]

Re: bad coil suspected

I was wondering what symptoms a single coil vs several bad coils would make? <br />Also whether the power pack would blow coils or vice versa?<br /><br />I will order a coil today and try it.

 

[Walker]

Re: bad coil suspected

What you describe sounds more like carburator problems than a coil. If a coil is leaking definitely replace it, but I'd tear down the carbs and give them a good soaking and rebuild.

 

[Solittle]

Re: bad coil suspected

Pull the plugs and check each one for spark. Spark should be a bright blue snap and jump around 1/2" gap. If the one with the melted insulation is bad or weak then you have confirmed the problem to be the coil.

 

[blackwaterstout]

Re: bad coil suspected

I agree with Solittle. A spark check is free. Check the spark on all coils. That will tell you a lot about your electrical system.

 

[RustynHouston]

Re: bad coil suspected

will do this weekend. still have family hurricane evacuation refugees in house now. thanks all

 

[mikeyzx2]

Re: bad coil suspected

you might not be able to get it to run if more than one coil's not firing. my '77 85hp has decided not to fire on 2/4 so it just about won't start and barely stays running if it does. just one coil dead will make it run a little rougher. my problem points to powerpack, as I got all new coils on mine and I've tested the stator with voltmeter. I got the OEM book if you need any technical info from it....it covers yours also

 

[RustynHouston]

Re: bad coil suspected

thanks Mikey, but I got my own manual and have some test meters but I may not have them all that the manual says I need.<br />My 115 starts fine. My symptom is ...WOT seems to be struggling, then all of a sudden it seems like the "rest of the engine" kicks in and off I go.....so fast - it scares me, so I pull the throttle back and I'm back to struggling again. <br />My engine doesn't even run rough. The only coil I have that looks like the insulation is melting is the only one where metal gets really close to the plastic. It must not be a bad coil (because the engine doesn't run rough at all) but I have one due in Friday so I'll put it on. Melting insulation will make it fail eventually.<br />I wish I knew if the power pack could cause my symptoms. I would change that out for slightly less than $100, but I know if I tear down the carbs I'll be in over my head and might as well hire it done..