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1984 Johnson 50hp wont "rev up" when engine cover is on.

N

numi

New member
Hi everyone.

Have some problem with my 1984 Johnson 50hp (model J50BELCRM), and I can't figure out what to do about it.

When the engine cover is on, the engine only runs at about 50% power. Removing the engine cover, it runs fine. That, in a nutshell is my problem.

Im wondering if something is shorting when I put the cover on, or what else it could be. I have had some troubles with the ignition only spark on one cylinder), and have just changed power pack and coils. First I thought I still had one cylinder that wasnt't firing, but now I'm not sure about anything anymore..

Any help most appreciated!
 
Thanks for the advice! Having done googling on exhaust leaks, it really fits the problem.

I'll test by spraying with oil asap. One questions, which points should I be looking at to identify the problem? There is the power head gasket, as noted Rwbutler. Any other potential leak points?
 
Thanks for the input!

I checked the cowl intake, nothing stuck there.

But I got an interesting update: When trying to start the boat, the battery was dead. I didn't think about it at first, so focused on testing the exhaust. I rope-started, inserted some oil and noticed a small leak from the base of the engine. However, I then proceeded to put the engine cover on. Well, that led to an interesting experience. When trying to adjust the cover I got a strong shock, from the cover. It was a real kick, not a tingle.

So, now Im back to wondering if I got a short, as the battery was dead. Could it be the spark plug wires? I found this post, indicating that the coil could be the wrong way or a wire damaged. Trying to find a pic showing correct lower coil installation, now the connections are pointing out, away from the spark plugs. It does put the wire very close to the cowling. Anyone know how they should be installed?

I also found this post, which seems to indicate that if not spark plugs/coils, it could be the stop circuit.

Im not good with electrics, so any advice on how to proceed more than welcome!
 
Last edited:
racerone said:
What does post #2 say ??
Click to expand...

yes, thanks, I noted that. Just wanted to make sure I got to the source of the problem (have to travel to get to the motor, so want to do all tests I can when Im there). If its the cables, I want to make sure the coils are on correctly, if that's whats causing the cables to go bad.

Ill test!
 
OK, to close this thread.

I actually switched the way the coils were installed, which moved the plug wires away from the engine cover. Runs really well after that! Then I also got some new spark plug wires as well, of course!
 
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