1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

[csgrizz]

I posted up about this motor (77 johnson 25 hp), "slipping" out of gear. When it first started it would barely "pop or bump" for literally a split second, and the shifter would not come out of gear. However, if you hold the shifter it did it LESS, but still would try to slip. We changed the prop, it continues to do it...it has been on multiple boats, and still does it (not a boat issue)<br /><br />Here is the kicker, based on all the suggestiosn here and other places I was sure we would find a worn out clutch dog when we took it apart...NOPE.<br /><br />Took it apart yesterday, and not only did the dog look ok, it looked new. The lower unit gears all look new as well, and there was no metal flakes in the lower unit fluid or water in the fluid.<br /><br />I am dumbfounded: What steps do I take now?<br /><br />Any suggestions? Please? Duck season is getting closer every day.

 

[JB]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Shift linkage adjustment? Matches manual specs?<br /><br />Vertical shifting rod? Solid connections at both ends?

 

[DJ]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

The edges of the clutch dog and the corresponding slot should have SHARP corners. No roundness on the edges is acceptable.

 

[Chinewalker]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

How were the splines in the end of the driveshaft where it meets the crankshaft? Any evidence of wear? It's possible that the crankshaft splines are getting worn, as they can rust out if proper grease maintenance during waterpump servicing isn't done...<br />- Scott

 

[wilde1j]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Does it slip out of reverse? I would bet the forward gear and clutch dog need to be replaced.<br /><br />Clutch dog/gear failure usually comes from 'gentle', slow shifting technique, rather than the proper way: brisk and firm. If you hear some clicking while shifting, it's too slow.

 

[csgrizz]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Thanks, for the info guys, I am actively searching.<br /><br />To add to your questions. The crankshaft splines looked ok to me, but I am untrained to what they should look like. <br /><br />Wildeone: It did not slip out of reverse. We tried flipping the clutch dog around and the problem got worse, it didn't just slip, it jumped completely out of gear.<br /><br />Thanks again for all the input.

 

[Dhadley]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Some clutch dogs were not ment to be flipped. Your results could be expected.<br /><br />I'd agree with DJ and WildeOne. The dog and gear need replaced.<br /><br />Good luck!

 

[Harker]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Chris, you mentioned on the DHBP that the shift rod clamp thing behind the plate had been jury rigged..is it not tight enough to hold?

 

[csgrizz]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Harker, <br /><br />I believe it is working like it is supposed to after my buddy Ron worked on it.<br /><br />Here is an update:<br /><br />Ron worked on it last night and reported that the shift linkage was definitely out of adjustment. He adjusted it and has yet to test it. <br /><br />I will update again later,<br /><br />CS

 

[csgrizz]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

One last update:<br /><br />The linkage was adjusted and the motor still popped out of gear. We changed the lower unit and the problem went away.<br /><br />We are taking the lower unit to a mechanic to have him take a look and see if he sees something we didn't.<br /><br />Good news is I have forward propulsion for duck season. <br /><br />Thanks for all the input.<br /><br />later,<br /><br />CS

 

[csgrizz]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

TTT<br /><br />Believe it or not the jumping out of gear thing came BACK like a bad habit. <br /><br />Keep in mind this is an entirely different lower unit. It started mid duck season and would just "hop" out of gear, and normally once I put it back in gear it wouldn't do it again.<br /><br />It continued to occur more often, until finally on the last decoy retrieving trip in March, it wouldn't even go into forward, had to use reverse to get to the boat ramp. <br /><br />What are the odds that two different lower units had the exact same symptoms?<br /><br />Does this mean it is something in the linkage or upper stem of the motor?<br /><br />I am mechanically stupid, so anything that can be suggested would be great.<br /><br />P.S. I never got the old unit to a mechanic to look at, so I can't give any input on what was found in the other lower unit.<br /><br />thanks,<br /><br />CS

 

[Chinewalker]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Different units doing the same thing - time to look outside of the unit...<br /><br />At the shift handle there is a bit of an adjustment to be had. There is a tension screw running horizontally front-to-back on the base of the handle, and another running horizontally side to side. Both should be loosened to adjust the shift handle.<br /><br />Also, I've seen a few of those motors that have had weakened springs, particularly if someone at some point has lost the original and replaced it with a door spring or some such. The spring is located at the top of the shift detent arm.<br /><br />And finally, I've also seen some where the detents in the arm get worn enough to slip between gears too easily. Something to look into....<br /><br />- Scott

 

[csgrizz]

Re: 1977 Johnson 25 hp still slipping...clutch dog looks NEW. HELP!

Just another update. AFter a few delays and running out of options I took the motor into a local marine mechanic. He told me that this motor and this problem are common and that it may cost $300 or more to fix it and chances are it will do it again in 3 months. He agreed to look at it and then let me know if he thinks it is worth fixing. This motor has great power for a 25 hp and has started every time even in subzero weather. <br /><br />Any suggestions?<br /><br />One more question. My father in law has a early 80's evinrude 25 hp. What are the chances that my 77 johnson powerhead would work on that system? <br /><br />Thanks in advance once again.<br /><br />later,<br /><br />CS