1959 10hp Johnson vibration

[Ashaman0]

I have a 1959 10hp Johnson which I use to get in and out of moorings and the dock for a 25' sailboat. This just started last Saturday last time i was out. About 10 seconds or so after starting up the motor starts vibrating really bad. The whole thing just shakes around, changing the throttle has no affect. If I kill it and restart it it will run smooth for about 10 seconds then the same thing happens. I have no idea where to start trouble shooting this problem. The motor still runs fine, but I am afraid its going to rip bolts of out of my motor mount or break the glass bulbs in the fuel pump/carb.

 

[ghamby]

Re: 1959 10hp Johnson vibration

Sounds like you are losing a cylinder. Check your plugs. Is one of them fouled?
Are you getting spark on both plugs?
Check compression. Are both cylinders within spec?
Just a start. Many posts here, search and read widely. good luck,GH

 

[Fuzzytbay]

Re: 1959 10hp Johnson vibration

sounds like its missing, perhaps a coil is going, or you have carbon built up on a spark plug electrode. Start by pulling the plugs, check them, test compression, (doubt that is the cause though) to be safe. Could be a bad/lose spark plug wire. Broken spring on the throtle advance roller, etc etc.

 

[Ashaman0]

Re: 1959 10hp Johnson vibration

sounds like its missing, perhaps a coil is going, or you have carbon built up on a spark plug electrode. Start by pulling the plugs, check them, test compression, (doubt that is the cause though) to be safe. Could be a bad/lose spark plug wire. Broken spring on the throtle advance roller, etc etc.

I just replaced the coil's so its not that. Thanks for the suggestions so far, I will give them all a check when I get home tonight.

 

[Ashaman0]

Re: 1959 10hp Johnson vibration

Looks like it was the coil. The wire coming out of one of the coils was rubbing on the drive shaft and it frayed almost all the way though. I installed a new coil but I am not getting any spark now. I could not get it to start up at all. I replaced the spark plugs as well and I am know at the limit of my understanding of the ignition system. What else could be going wrong? What does the condenser do? How can I check if my spark plug wires are ok? I hear everyone saying they check the points when they are working on the ignition system, what does that mean?

 

[Fuzzytbay]

Re: 1959 10hp Johnson vibration

It possible your points slipped closed while changing the coil, check to see if they move open and closed while you revolve the crankshaft.

 

[Ashaman0]

Re: 1959 10hp Johnson vibration

replaced a coil which had one of its wires stripped, and replaced the condenser and spark plugs. Ignition seems to be working well. Runs if I spray fuel into the carb but its not running on its own. I think I have some problem with my carb now I need to figure out.