78 johnson weird noise issue

[mmawonder]

A couple days ago, I was re-adjusting the slow speed needle on my 78 johnson 25 so I was runnig it without the cover. When I was runnig the motor I realied there is some kind of ticking noise comin off the cylinder block. It is very distinctive and the intervals speed up as I raise the rpms. During idle i'd say hear it about 2-3 times per second. Funny thing is it sometimes goes away and runs quiet for about 10 seconds, then the ticking comes back. I have 2 friends of mine with 2 different diagnosis. One says it is a worn piston that is slapping against the block, the other says it is a ring sticking. I dont know what it is. The consition of the motor is pretty good, compression shows 100 and 120. I just ran half a can of seafoam deep creep yesterday and let it soak overnight. This morning I started the motor and cleared the seafoam but the noise is still there.

Any suggestions?

 

[mmawonder]

Re: 78 johnson weird noise issue

bump still looking for an answer

 

[Rick.]

Re: 78 johnson weird noise issue

Try giving it some choke when the noise is occurring and see if it goes away. If it does, Open your slow speed idle a little more. (richer) Just a thought that it might be sneezing you hear although I've never heard it several times in one second. Rick.

 

[mmawonder]

Re: 78 johnson weird noise issue

I have sneezing issue too, well when the motor first starts if its idling at a certain rpm it will drop it really fast and build it back up to where it was originally within one or two seconds, and it does this once every 5-6 seconds until warm up.

Oh and it also starts very hard, usually 10-15 pulls, and once in a while after it starts it will stall and wont start for like 15-20 minutes, then it will start again.
I cleaned and rebuild the carbs, ran a can of seafoam and played with the slow speed adjustment which has a very small sweet spot.

 

[Rick.]

Re: 78 johnson weird noise issue

If it is sneezing you haven't found the sweet pot. Are you giving it enough throttle to start it? You never mentioned if the sneezing goes away by giving it a little choke. Rick.

 

[mmawonder]

Re: 78 johnson weird noise issue

sneezing goes away with a little choke or after warm up.

 

[Rick.]

Re: 78 johnson weird noise issue

If the sneezing goes away with a little choke the you need to open the slow speed needle some more. It is running lean. Just open it in 1/4 increments and you'll find a spot where it stops. I believe it will help it to start easier as well. Rick.

 

[mmawonder]

Re: 78 johnson weird noise issue

Well rick the sweet spot on this motor is i think very small, I mean the difference between too lean and too rich is les than 1/4 turn on the motor.

 

[Rick.]

Re: 78 johnson weird noise issue

That's OK as long as you find it. Did the sneezing issue get resolved? Is it easier to start or are you saying these things haven't changed? Rick.

 

[F_R]

Re: 78 johnson weird noise issue

Sneezing after starting is normal until it is warmed up. Don't try to adjust it out of a cold engine or it will be too rich once it is warmed up.

Now about the ticking. I really can't say without hearing it, but want to mention that those motors make a lot of noises, compared to something like a Toyota. Outboards have needle bearings that normally make noises because they can't run with tight clearances and oil layer like plain bearings. The pistons are also pretty sloppy in the bores, at the head end. The skirt ends are tighter. But they do rattle around in there. I have never seen anybody that could hear a ring sticking. He must be good.