15 HP Evinrude help - No power or rpms

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wmk0002

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I posted about this motor on another forum so I am copying and posting that original post here below:

I have a relatively new to me 1982 Evinrude 15HP, model E15RCNC. I bought it based off having good compression and that the seller ran it in a barrel at low speed on top of a good price. Since I have bought it, I have checked the impeller and LU oil and both are in good shape and the motor is cooling. I rechecked compression and got 110 psi on both cylinders. I installed a helicoil into the stripped recoil starter hole and now don’t have to use a rope on the flywheel. I checked spark and both are jumping a ½” air gap on my spark tester.

The first time I tried it out on the lake I was in a 1436 flatbottom. I had previously just ran an old Sportwin 9.5 hp and got a decent 16 mph out of it on the boat so figured this one would do much better. First blast off it took off with good power and immediately bogged down to just a few mph. Back home in the barrel I rechecked everything I did prior and after convincing myself it was good I gave it another lake test on my new 1648 Alumacraft flatbottom. Same bogging, lack of power, and slow speed/low rpms as before. FWIW the Sportwin did 15mph on this hull.

This time, I rebuilt the carb. The old one was clean but the needle was sticking some. Lake tested again and got the same results. This test though I tried pulling plug wires. Pulled one plug wire and ran the motor and it ran like when both were plugged in…so I thought it might have dropped a cylinder. But then flipped it and it still ran, just slightly worse. So both cylinders are firing.

On to working on it again in a barrel at home, I pull the plug wires while it’s running at a somewhat fast neutral idle and have the same results as on the water however I notice massive arcing from the disconnected coil to the block and other coil. It does this when either plug is disconnected. Is this a sure fire indicator the coils are bad? Or should that be expected when they have such a high charge and nowhere to dissipate the energy to?

I will add I have not installed new plugs yet. They are the correct ones though in that they are Champion QL77JC4. Neither looks totally fouled although one does have some white spots on it. I know I have compression, spark (at least to the plugs), and fuel (I’m confident in my carb rebuild as I was very thorough). In all of my tests I tried pumping the primer bulb but to no avail, gas was fresh and properly mixed, and vent cap open. Does this seem like fouled spark plugs? Or does the coil arcing I mentioned indicate something else? I am buying new plugs today and ordering new plug wires too. I’m looking for advice as to what the problem may be and what to try next if new plugs and wires don’t do the trick. I definitely don’t want to go throwing money at the ignition system until I know for sure what is at fault in it, if anything.
 
I bought some new Champion L77JC4 plugs today. I also bought some of the sprayable Seafoam Deep Creep to use on a on the water test to see if fuel starvation is an issue here.
 
You're pretty thoroughness I'll give you that!
I have to question any coil that is arcing to the surrounding structures

Sent from my LGL31L using Tapatalk
 
dahut said:
You're pretty thoroughness I'll give you that!
I have to question any coil that is arcing to the surrounding structures

Sent from my LGL31L using Tapatalk

Thanks lol. I try to tell the whole story up front. I'm pretty competent when it comes to outboards but electrical/ignition problems frustrate me to no end and I'm fairly sure that's my problem. I'm confident fuel delivery is not the issue and compression is what it is.

I question arcing coils as well because they are supposed to be isolated aside from the high tension spark plug leads. I'm not familiar with this motor nor its coils but imo the hardened resin/epoxy or whatever it is that they seal them with feels almost tacky on both coils instead of smooth. Seems strange for both of them to be this way though if it is a problem.
 
I would replace that coil for sure

it probably has carbon tracking and you are losing spark though it under load.

I would be inclined to replace both coils And the plug wires as well since you are in there.
 
I can't see how it can be much else, with all the diligence you've put in.

I'd follow Mr. Perchjerkers advice

Sent from my LGL31L using Tapatalk
 
I think I will do that.

Does anyone have a brand recommendation? The OEM, CDI Electronics, and Sierra brand coils are all priced very similarly for this motor.
 
Thank you for providing the link.
Would you undertake to explain the "power pack" shown in the parts breakdown.
I'm thinking "exciter" or pilot coil, but I haven't done that research.

Sent from my LGL31L using Tapatalk
 
From what I remember from the service manual, the power pack sends out about 200-300V to the coil (as powered by the stator, and signaled from the trigger/timing sensor). The coil then supercharges that to multiple thousands of volts to make a good spark under compression. To my knowledge, if the powerpack fails, you totally lose spark to one or more cylinders either all the time, sporadically, or after the powerpack gets hot and fails/shorts. I had this problem on my 70hp...it would drop a cylinder after running for a few min when the powerpack began to heat up. Costly fix as it was about a $250 part if I remember right.

I'm not losing any spark from what I can tell so I think the powerpack is ok. I do have an inductive timing light I can use on the water which can help me verify if it comes to that. I also have a 9.9hp which has a compatible pack I can swap over to this motor and test. Actually I would try that with the coils too, however, despite being the same model year motor, it has the older style rounded coils for whatever reason.

Hope my powerpack explanation makes sense. I can read up on better from my service manual when I get home.
 
Yes you explained what I'm referring to as a "pilot coil" very well.

Sent from my LGL31L using Tapatalk
 
I captured some video for yall just a little bit ago.

https://www.youtube.com/watch?v=qMg2AfyNkrU

I ran the motor at a fast idle and pulled each plug separately. As you can see, each coil arcs to the engine block and occasionally to the other coil as well. Looking more closely (and seen in the picture below) the back portion of the coil that contains what I call insulating resin (?) is not just tacky like I previously mentioned but actually mushes when I press on it hard. Also, only one coil has a part number on it but from what I can tell that part number is for a 5 and 6 hp motor. Maybe this motor had the wrong coils and they have been damaged by seeing too much voltage from the powerpack than they are built for? I don't really know, however, I think my best bet here is to buy 2 new OEM coil kits. That way I know that the coils, wires, and plugs are new and not the cause of my headache.

I'm about to look through my service manual one last time to see if there are any more tests I can perform before ordering though. I have a DVA adapter for my multimeter so I should hopefully be able to verify that at least the ignition system up to the powerpack is working correctly by outputting the correct voltage range.

Pics:
D343133C-77E6-4D92-A139-3B703A5CC105_zpsqahxfsbf.jpg


1B5A5C28-9CA9-474F-9844-91C02DF8260E_zpsqrx5bw0y.jpg
 
Wow you are thorough.
I like that.

I'm calling you if I ever need help with an outboard engine!

Sent from my LGL31L using Tapatalk
 
Thanks, but let's see if I can get this one fixed first lol! Fingers crossed new coils, plug wires, and plugs will do the trick.
 
those coils are definitely shot.

replace everything like you are planning

just an fyi it takes more spark to fire a cylinder that is under load than it does at light load or idle

so its leaking spark though those carbon track when you are running it
 
perchjerker said:
those coils are definitely shot.

replace everything like you are planning

just an fyi it takes more spark to fire a cylinder that is under load than it does at light load or idle

so its leaking spark though those carbon track when you are running it

Thanks for the vote of confidence perchjerker.
 
:thumbs up:
You had me at widespread arcing, the wrong type coils, and potting compound tturned to soft mush

Sent from my LGL31L using Tapatalk
 

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