1975 25hp johnson slipping out of gear

[jbjennings]

Re: 1975 25hp johnson slipping out of gear

Coldpat,
I would have turned the dog around and gave it a shot, too. But if it does work I would still keep an eye out for some NOS gears and clutch, or a used lower unit that is in good shape. Your lower unit looked good and rust-free anyway. Those worn gear ears and clutch dogs aren't gonna last long either way. I would also consider seeing if a machinist could reshape the clutch dogs and gear ears and then re-caseharden them. I've heard this is possible but have never tried it. But it won't hurt to ask around.
Good luck,
JBJ

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

thanks for the Advice. I was thinking the same thing. The motor is at an age where I need to start looking for parts on the cheap before they all go away. The clutch dog wear on the reverse side was very minimal. the forward gear look good except for the wear on the front surface of the lobe which should not make a difference unless it is worn down. Thanks for the help. How do I become a Master Chief? I was in the Navy and made it up to a 2nd Class Petty Officer. I know this don't count but its funny to me

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

JB, I'm from Louisiana too. Living in Texas now.. From a little town called Mamou. Heavy French speakers.

 

[jbjennings]

Re: 1975 25hp johnson slipping out of gear

Ha Ha!!!!
I just noticed when you mentioned it that I was now a "master chief".....Sounds really important, eh??? It actually is determined by how many posts you've made on the forum and has nothing to do with how much you know I've heard of Mamou, but I live only about 5 or 6 miles from Arkanasas so a little far from there.
Good luck with your johnson,
JBJ

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

ran motor in driveway with square rabbit ears. Took the remote shifting off the manual shift on engine and it shifted a little to easy into gear. It was reallly really smooth. Remember, I re-sealed the lower unit and reversed the clutch dog.

I'm going to take the kids for a ride in the morning to test under load

 

[wilde1j]

Re: 1975 25hp johnson slipping out of gear

Running the motor in the driveway doesn't tell much other than it runs and shifts. The real test will be under load. Don't be too surprised if it starts popping out of gear after a while, since the fwd gear recess is probably compromised, if the clutch dog was rounded. In any case, you now know how to pull the gear case apart quickly. Make sure to shift briskly!

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

ok, I'm confused.. runs good in slow but when I take off it just revs up. no jumping out of gear... just spins... then when I slow down it keeps going. Help!!! It doesn't seem like it is popping out of gear. Took off the front control cable and it did the same thing.

 

[ezeke]

Re: 1975 25hp johnson slipping out of gear

Did you check for a spun prop?

 

[wilde1j]

Re: 1975 25hp johnson slipping out of gear

Sounds like you may have a spun prop hub. Very easy to check ... put a mark on the inner metal hub and the aluminum of the prop. If the marks move relative to each other with the motor running under load, then you need to get the prop rehubbed by a prop shop (not a do it yourself job). The key is "when I slow down ...")

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

what is a spun prop? What do you mean mark the hub then mark the prop?
This might be the case because it doesn't seem like it is jumping out of gear. And when I had it apart looked like the clutch dog went in pretty far.

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

can a prop with shear pin be spun?

 

[ColdPat]

Re: 1975 25hp johnson slipping out of gear

Don't answer that last question. I put the shear pin into prop and turned it with needle nose pliers....how much does it cost to fix propeller?

 

[ezeke]

Re: 1975 25hp johnson slipping out of gear

There are two sections to the propeller with a rubber seal in between. The seal is designed to break on impact to protect the gearcase.
On your propeller setup, use the rounded end of the cotter pin as a pointer and scribe a mark adjacent to it on the propeller.

If after running, the scribed mark is no longer adjacent to the cotter pin, the outer propeller is slipping on the inner hub and needs repair.

The drive pin at the back of the hub can also break on impact, or from the propeller being too loose on the propeller shaft.

 

[ezeke]

Re: 1975 25hp johnson slipping out of gear

Sorry, you got that in while I was typing. There are usually prop shops around metropolitan areas.

Few dealerships repair propellers, but they can usually tell you the ones that they send work to.

Iboats is usually having a sale about this time of year and they have gotten my new propellers to me in 3 days or less - its worth considering.

Here's a link to a national list of propeller shops. If you select Chesapeake Bay from the pick List, it comes up with a lot of shops: http://www.sfsailing.com/cgi-bin/mbi/propeller.cfm

 

[jbjennings]

Re: 1975 25hp johnson slipping out of gear

That's great advice as usual from Ezeke, if I could add about the prop--I'd do like Ezeke said and get a new one or a used one on ebay. Sometimes the props will break when they're old and brittle when they're rehubbing them. You can probably get a new one as cheap or cheaper than a rehub. Then again, sometimes used props on ebay look great in the pic but aren't very straight when you get 'em. Usually good enough, though.
JBJ