Clutch dog question

[marcysibyll]

Got a 1972 25HP Johnson. Jumps out of gear. What are the ears on the clutch dog supposed to look like? Mine are rounded at all 4 outer corners of the ears. Looks as tho they were machined. I did find new for just over $100.00, but don't want to spend it if the problem is somewhere else.
Thanks

 

[wilde1j]

Re: Clutch dog question

Let me quess ... it pops out of gear above idle? Go for the new clutch and a new forward gear. Shift promptly (don't baby it into gear) and it won't happen again soon.

 

[jwilkey84]

Re: Clutch dog question

I just got done messing with a 1972 johnson 20hp that had the same problem. Yes they have a rounded shape, but they should have 90degree edges. that is where it gets to jumping. Someone told me to take a dremel tool and grind on the clutch dog ears to make all the edges 90 degrees again. I tried it and it is working great. I guess my best illustration on how to make it look would be like a tin can standing on end. As you look down on the can it has the appearance of a circle. As you look at it from the side it has the appearance of a rectangle. your clutch dog ears should look similar. It is worth a try and if you are the least bit handy, this could save you $$$$.

 

[marcysibyll]

Re: Clutch dog question

I know exactly what you mean. Since the motor is old enough to vote, and drink legally, I will try your "fix" before shelling out the big dollars. Can always spend money. It's destined to be the main motor on my 14 ft Grumman,which sees water about 3 times a year and I'm tired of pulling the rope on my Johnsion 20.

 

[bflat]

Re: Clutch dog question

Yes, I read that same advice about taking a dremel tool to the ears on the forward gear. My 10 HP QD-20 just wouldn't stay in forward. When I took the lower unit apart the ears on the forward gear didn't look too bad. There was quite a bit of wear on the clutch dog ears though - so I turned the dog around (thinking reverse wasn't as important as forward). When I put it back in the water - same problem.
Then I researched the problem and found that suggestion about grinding the gear ears in these forums. So I bought a little dremel-type tool (I think a drill with a very small grinding bit - the kind used to sharpen chain saws - would work too - but my drill was at the cottage -sigh-)
Long story short - even though the ears in the forward gear didn't look too bad I grinded them anyway (using that small grinding stone - the kind for chain-saws). I tried to smooth out the clutch dog ears a bit too (this is tougher) and I turned the dog around so that the least worn ears were engaging the forward gear. Guess what - it worked like a charm. No more jumping out of gear.
I think the trick is to make the mating surfaces between the clutch dog and the gear as flat as possible (I even ground the gear ears down a little deeper towards the back so as to actually pull the clutch dog in under pressure - surely a bad idea - but I did it anyway) You should also make sure to grind an equal amount from each gear ear - but not having machinist tools we'll probably have to guesstimate this part.
Worked for me (if you're the person who made the suggestion - I owe you a beer!)

Steve

PS I was having no luck at all with that Permatex Aviation sealant (brush on type). When I switched to the Permatex gray tube sealant (suggested for crank cases and so forth on the label) I got much better results. So far at least.

 

[wilde1j]

Re: Clutch dog question

You're aware that those are hardened surfaces, and grinding removes what's left of the hardened stuff? Won't last like the real thing, but may go for a couple of years, depending on the amount of shifting. For a couple of bucks you could get a machine shop to properly machine and perhaps harden the metal.