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1983 Johnson 35 HP - jerks at high loads

K

kevsterini

New member
My '83 Johnson 35 HP is awesome but.... When I first got it used about 5 years ago it was jerking (felt like a hard knock or "miss") at higher loads and soon turned in to more frequent and at lower loads until it finally wouldn't go anymore. I replaced the forward gear and main drive beveled pinion gear because when I broke the lower unit down the main drive gear was pretty much smooth (no teeth left). I did carb work to it put it all back together and it worked great until this weekend. I started doing the jerk thing again. I change the lower end oil every season and have had no problems. I'm sure this is the same issue starting to happen again. Why does this happen? Because if I fix it again I want to do what I can to make it stop. I can't change this every 3 to 4 years. Any suggestions or help are appreciated.

Thanks in advance,
Kevin
 
OK, it may be a "lean sneeze" as people are suggesting, but if it is the original problem reappearing, it is back to the lower unit. The banging or jerking under power is the clutch dog disengaging from the forward gear, rotating half a revolution, and slamming back into gear. That violent slamming may be what caused a gear tooth failure.

You will have to go in again and examine it to see what happened.

The most often cause of early clutch dog / forward gear failure is improper shifting. Shifting should be done at dead slow idle, and with a quick, snappy movement. Trying to gently ease it into gear is the worst thing you could possibly do.
 
Thanks fdrgator, Great suggestions and that is exactly what I learned from the last time so I am always careful to snap it in gear with a quick motion and always at super low idle which is not a problem because this motor idles great. Is there a spring that should keep the dog engaged? or just the torque and gear geometry that does it. I've taken great care of this and this shouldn't be happening. Thanks again.

fdrgator said:
OK, it may be a "lean sneeze" as people are suggesting, but if it is the original problem reappearing, it is back to the lower unit. The banging or jerking under power is the clutch dog disengaging from the forward gear, rotating half a revolution, and slamming back into gear. That violent slamming may be what caused a gear tooth failure.

You will have to go in again and examine it to see what happened.

The most often cause of early clutch dog / forward gear failure is improper shifting. Shifting should be done at dead slow idle, and with a quick, snappy movement. Trying to gently ease it into gear is the worst thing you could possibly do.
Click to expand...
 
I don't have an original service manual no. I've looked up everything I needed so far online and forums like this one. So I think what you're saying is I could get a jerk like this that feels like a gear skip but is really just a carb cough or something? Do I have that right?
 
It is easy for an inexperienced person to mistake a lean sneeze for a clutch dog problem. But they really are quite different animals. You probably are familiar with the sneezing that normally goes on after a cold startup. On the other hand, a dog is a violent banging that happens under power, while accelerating or running wide open throttle. Most people describe it as feeling like they hit a log (or here in Florida, a gator). A third interruption type is an ignition miss, random and / or momentary and much milder that the dog banging around.

Yes, the spring and balls through the center of the prop shaft are supposed to help keep it fully engaged with the gear. (Sort of). It is of more value in ensuring a snappy movement of the dog by making up for slop in the linkage. Absolutely no way can it hold a worn dog in engagement with the gear.
 
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