1972 johnson 100 hp outboard clutch dog problem

" I have a 1972 Johnson 100 hp

" I have a 1972 Johnson 100 hp outboard. The motor trails out for a split second and then slams the transom. This has been going on for four to five years. I happens very quickly and I can't tell if it is the motor momentarily stoppin and starting again or if the clutch dog is slipping. It happens at any speed, sometimes two or three times in a row and then not again for a whole day. It seems like if it was a clutch dog it would do it constantly. Sometimes it happens when we are pulling a ski-er and sometimes at idle. Obviously the violence of the slam down onto the transom depends on the speed we are going. I have ruled out water in the gas, the shifting solenoids, bypassed the ignition, switched props, checke all the grounds. But there is something I am missing. What is it?

Mike "

"Michael.... That engine has a

"Michael.... That engine has a spring loaded shifter clutch "dog" that engages forward gear when "NO" voltage is applied to the lower unit. For a full explanation of the system, do a keyword search to the left of this page for the topic Hydro Electric. Your engine is jumping in and out of gear, giving the sensation that you are hitting something.

Joe "

" Joe,

I agree with you. I

" Joe,

I agree with you. I have already checked the shifting toggle switch at the control box and the voltages to the blue and green wires is correct in each gear. With both wires disconnected and the lower unit defaulted to forward gear, the motor still kicks up for a split second. The greater the pull on the boat from the ski-er or the flatter the boat is trimmed out under hard pulling the more the motor kicks up. I think the clutch dog is engaging and disengaging for a split second. From my repair manual it looks like I can remove the propellar shaft without complete disassembly of the lower unit and then replace the clutch dog if neccessary or at least visually inspect it and then replace seals and reinstall the propellar shaft. Is this possible? Thanks for you help.

Mike "

"Mike.... Yes you can remove t

"Mike.... Yes you can remove the prop shaft w/o completely dismantling the L/U. I'm wondering if you may be using the wrong gearlube. You can not use "HiVis" lube in that gearcase. You must use "Preminum Blend" also know as "Type C".

Joe"

" Joe,

Thanks for the info

" Joe,

Thanks for the info about removing the propellar shaft without a complete disassembly of the lower unit. That will save me a tremendous amount work. I have the Premium Blend gearlube in there. Do I need special snap ring pliers to remove the snap rings that hold in the propellar shaft? That is are they longer than normal snap ring pliers or do they lock somehow when engaged. In my repair manual it says to be very careful when removing the snap rings. If I need special pliers where do I get them? Finally in the manual it says to put some type of special grease between the seals when I replace them. Do you know what type of grease this is and will the place that sells me the new clutch dog, if that turns out to be what I need, have it also?

Again, thanks so much.

Mike "

" Mike,

When I took the sna

" Mike,

When I took the snap rings out of mine last week, I got the biggest pair(Longest overall length) of snap ring pliers they had at the local Car Quest automotive store. I still had to make longer extensions for it using allen wrenches. My problem was that my lower unit was in neutral at all times. With the prop off the shaft, it would spin freely in either direction. Got the lower unit off, took half way apart and for some reason it went back into forward before I got to remove the shaft. Still took everything apart. Did not remove clutch dog from shaft though. Couldn't find anything wrong. Replaced the seals on the propeler shaft houseing and on the drive shaft bearing housing, as well as the o-rings on them due to water getting into the lower unit oil. Brought boat out on water and everything worked great for about 10-15 minutes. Then when I would get above 1/2 throttle in forward, it would just rev up and not increase speed. Up to 1/2 throttle forward, neutral and reverse works fine. Next step I guess is to bring my prop in and have that checked.

What do you think Joe???

Scott "

" I started new thread with my

" I started new thread with my problem.
1972 85Hp Johnson "Slipping"

Thanks,
Scott "