Lower unit thumping

[Trem62]

Hi all, I am new to boating and just bought a fixer upper boat and motor.
The boat is fine (now) and the motor is fine too, the problem is a thumping in
I think the lower unit. When i am driving along, the motor like kicks back almost like a skip, It does it about every 4 to 5 seconds nomater what speed
worse at high speed bigger thumping. Who knows tho, it still may be in the motor skipping (it just don't seem like it tho. The motor is a 1989 johnson outboard 88hp. Any help at all or things to check would be great. Thanks Norman T

 

[F_R]

Re: Lower unit thumping

Sound like you keep running over stumps? That's the clutch dog and forward gear in the lower unit. Hope you have deep pockets.

 

[Trem62]

Re: Lower unit thumping

Hey, It's like living in swamp land, and yelling out STUMP. Sound like a good winter project try myself. Very good with transmissions. Thanks for the help, but I thought it might be an easy fix. Norman

 

[tashasdaddy]

Re: Lower unit thumping

FR probably is right. But, disconnect the shift cable at the engine, and put it in gear manually, sometimes the cables are streched, on miss adjusted. it's worth a try. if this doesn't solve it don't run the motor or it will only get worse, and not go in gear at all, leave you paddling.

 

[Trem62]

Re: Lower unit thumping

Well, I took it apart, and found a bad clutch dog (rounded edges) and forward gear where the clutch dog engauges on the gear (also rounded). I have a offical johnson manual and just for ****s and laughs I am doing it myself. I am buying all the tools needed and new parts too. a few things tho I will need to remember how each bearring is put back in (what side is up or down) to case. Is their anything else to do or any info to make it go a little bit smoother so I have to make mistakes and take it back apart. Thanks for the help. Norman T

 

[F_R]

Re: Lower unit thumping

The biggest cause of that is trying to be gentle with it. When you shift, do it quickly with decisive snap. Trying to ease it into gear gently is death on the dog and gear.

 

[Trem62]

Re: Lower unit thumping

Well that's good to know. Thanks Captin for all the help. Norman

 

[c22jrc]

Re: Lower unit thumping

Had the same symptoms with a 1988 Evinrude XP100. Found a great deal on a gear set from Gear pros and proceded to tear into the problem. After removing the gears they looked fine. Took them to my local Evinrude mechanic an was told they wouldn't haave caused my problem. This was the first time I had ever pulled a lower unit and did find that the water pump should be rebuilt. I replaced seals and gaskets and put it back together. NOW I still don't know what was wrong???? I'm still not sure how the top of the shifter rod with the small hole connects to the cable? The pin I had to remove to drop the lower unit goes into the linkage at another location.
The pictures in the manual are not very helpful.?????
Thanks