1977 9.9 running on 1 cylinder

[Bitmess]

1977 Johnson 9.9 10R77A
Compression-Just checked it.
1=100
2=100
Spark looks good on both plug wires and feels pretty strong running through my arm. (don't ask)
It seems to lack power. I can't quite get a 12' joh boat with 2 people on plane.
I removed the plugs and they look ok, so I re-gapped them at .30. They were gapped at .40 for some reason. Then I noticed a crack running the the full length on the bottom coil so I ran it in a bucket at a medium idle.
I removed the top plug wire and the motor stalls completely. When I remove the bottom wire, it keeps running and really doesn't sound any different. I'm having trouble doing this because I keep getting shocked as soon as the wire clears the plug even with a rubber handled pair of pliers.
The plug wire looks good but I'm not sure it is.
I'm pretty sure I have a bad coil but I wanted to get advice frome the experts before I start spending a bunch of money.
Thanks!

 

[James R]

Re: 1977 9.9 running on 1 cylinder

These motors are prone to corrosion in the plug wire connectors. Switch the plug wires and see if that shifts the cylinder firing.
Try using a heavy leather glove to pull the wire off.
If that doesn't do it you can switch the wiring on the coils, both primary and secondary, to see if it is a coil.
The coil terminals also get dirty so look for that also.
Of course switching plugs may show something.
New plugs are a given.
If that fails then look to the wiring.

 

[Daviet]

Re: 1977 9.9 running on 1 cylinder

They do make special pliers for removing plug wires, just sayin.

 

[petryshyn]

Re: 1977 9.9 running on 1 cylinder

http://forums.iboats.com/showthread.php?t=334335

 

[Rick.]

Re: 1977 9.9 running on 1 cylinder

You should get a spark tester and check to see if your getting spark to both cylinders. If you are getting a good blue/white spark that will snap across a 3/8 inch gap then try switching your plugs to see if you have a bad plug. If your not getting the spark I would change both coils. I'm fairly sure the coils on that year have new plug wires coming out of them (factory assembled) so you will be getting new plug wires at the same time. If you suspect it is just a plug wire try firing it in the dark of night and you will more easily see spark making it's way to ground. I got some really thick almost rubber tape from an electrician and wrapped my plug wires and it did the job. I have no idea what it was called but it is different than any electrical tape I ever saw. Best of luck. Rick.

 

[petryshyn]

Re: 1977 9.9 running on 1 cylinder

Rick
The tape is called "rubber tape" but it is not fuel/oil resistant and will make a gooey mess if it come in contact with petroleum products.


cheers

 

[Rick.]

Re: 1977 9.9 running on 1 cylinder

Thanks for that. I better be careful but shouldn't get any fuel back there I hope. Rick.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

Thanks for all the good info!
I went and picked up 2 new plugs and a plastic plug wire puller. I'm gonna wear gloves too.
I'll change the plugs tonight and re-test.
I've been thinking. Since I have what seems to be good fire at both plug wires, it could be just a spark plug.
I'll keep you posted as to how it goes.
Thanks again.

 

[jay mendoza]

Re: 1977 9.9 running on 1 cylinder

Or a bad/weak condensor, MAY deliver spark, but the spark gets intermittant under load. Check it if the plug or coil is not the problem.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

I installed the new plugs and #2 still isn't firing. I checked the plug wires for corrosion. I checked all the grounds. I can't figure out how to remove the plug wires from the coils and I don't see any way to swap the coils without cutting electrical wires.
I did notice that on #2 when I pull the plug wire off while the motor is running, spark shoots out of the wire above the boot instead of out of the end of the wire. Would that be a clue that the plug wire is broken just above the boot?
Thanks again guys.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

This is what my coil looks like. Is it possible to remove the plug wire without tearing it up?

 

[bktheking]

Re: 1977 9.9 running on 1 cylinder

The new coil comes with a plug wire, just buy a new coil and be done with it.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

I do feel like I'm beating a dead horse here.

 

[Daviet]

Re: 1977 9.9 running on 1 cylinder

Swap coils cylinder to cylinder and see if spark changes with coil swap. If spark moves with coil swap, you have a bad coil. If it doesn't move with coil swap, you may be looking at a defective power pack.

 

[bktheking]

Re: 1977 9.9 running on 1 cylinder

I do feel like I'm beating a dead horse here.

No not beating a dead horse, I guess I wasn't clear, my bad. The coils physically swap, plug wire and all. If you swap them and the spark changes with swap then you know you have a bad coil. The plug wire will come installed with the replacement coil, don't bother messing with swapping wires.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

Okay, i swaped the coils. I cut both orange wires leading into the the coils and swapped them. then I took the wires off the plugs and swapped them. I started the motor. When I pull the top plug wire, the motor stalls. When I pull the bottom wire the motor continues to run and doesn't bog or anything.
I am assuming that it should bog or stall when I remove either of the plug wires??

This is exactly what it did with the coils arranged the original way.
So, probably not a coil??

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

Any other ideas guys?
Thanks

 

[Daviet]

Re: 1977 9.9 running on 1 cylinder

I just went back and reread all of the posts, and noticed that you said that you DID have good spark on both cylinders, correct, I don't know how I got off track. Maybe I should slow down when reading. If so, your ign system is OK. It only takes three things to make an engine run, compression, spark and fuel. If you have good spark and compression, it only leaves fuel. Has this engine been sitting for awhile? Looking at the parts breakdown it looks like the carb is mounted in a direct line to # 1 cylinder and #2 cylinder has to downdraft fuel mixture, thinking reed plate stuck. Maybe try one thing, with engine running in a barrel, try squirting some fuel mixture in the carb and see what happens. This is one of those problems that keeps a guy up at nignt.

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

Please don't lose any sleep!
I got a good education on troubleshooting the ignition system in the last week.
I got in contact with the gentleman that sold me the motor. Turns out he's a mechanic that specializes in these small OMC outboards. He is also repairing it for free. What a guy! We are going to tear into it today. The reed valve sounds like a good place to start. Last night, I pulled the plug wires and cranked it over a few times then removed the spark plug on #2. I put my nose close and I smelled some fuel but was it enough fuel?? I'll keep you all posted as to what we find out.
Thanks!

 

[Bitmess]

Re: 1977 9.9 running on 1 cylinder

Success!
We changed the power pack. Now it's running on both cylinders. I can pull either plug wire (one at a time) and the motor continues to run. I'm going to take it for a test drive tomorrow. I went ahead and did a partial decarb as per the instructions here on the iboats forums. I'll finish that up at the lake tomorrow. I am impressed with the fairness and honesty the the previous owner has extended to me. He gave me the power pack. He even installed it and we tested it. He did make me do the plug wire pulling since I'm a little younger and my ticker might handle the shock better