Jerking motor. clutch?

htuong95

Seaman
Joined
Oct 7, 2005
Messages
56
Hi all,

I have a 1979 35hp Johnson outboard. I took my boat out today and the motor jerks about every 10 secs. It jerks more at faster speeds. I think it is the clutch. I ran it in reverse and it still jerks. It ran fine a week ago. Three days ago I adjusted the Spark plugs gap to 0.030. Could this play a role in the jerking? Maybe the linkage is adjusted wrong? It jerked before a year ago but it went away.

I have changed the clutch and seals on my 1979 4hp Seaking motor and It wasn't too bad. The only difference is that the Johnson has a reverse gear. How hard is it to change the clutch and seals? I already have the seal kit for it and the service manual. I don't want to crack the lower unit open if the problem is something else. Thanks inadvance.

-Hong
 

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: Jerking motor. clutch?

Hong,
It definitely sounds like a clutch dog. I hate to say it, but as much as I hope you can get away with just a clutch dog, you may need more.
It's not too bad of a PITA to change it if you've done one before.
--no, adjusting the spark plug gap won't cause what you describe.
Good luck,
JBJ
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Jerking motor. clutch?

If you continue to run it that way, with the clutch dog jumping, it will beat the linkage to death too. If it hasn't already.

It is unusual for the dog to wear without also wearing the mating area of the gear. Expect to have to replace both. Putting a new dog against a worn gear will only wear out the new dog very quickly.
 

htuong95

Seaman
Joined
Oct 7, 2005
Messages
56
Re: Jerking motor. clutch?

Thank you all for the help. $82.92 for the clutch Ouch! The forward and reverse gears are $$$. I just hope all I need to replace is the clutch. Crossing my fingers. I have to shop around for a better deal. Thanks again.

Hong
 
Top