stripped drive coupler??

[nice-diver]

75-76 johnson 25hp

cruising to dock...BANG..rev. pulled prop= good shear pin, shifter moves with little bit of detent (not my boat, never really shifted it before) prop turns gears so final drive must be intact

**is there a coupler on the end of the crankshaft?? that is stripped
**is the shifter unhooked/ broke while under power?

thank you

 

[Haffiman]

Re: stripped drive coupler??

Might be a drive shaft/splines failure.
Is water pump still working?

 

[5150abf]

Re: stripped drive coupler??

Could have been the clutch dog, it is in between the gears and it could let go and still allow the gears to turn, you really need to open it up to see what let go.

Here is how a lower works, the drive shaft comes down from the engine, there is a pinion gear on the end of that, it is in constant contact with both forward and reverse so if the engine is running the gears are turning, on the prop shaft is the clutch dog and it is pinned to the prop shaft and slides forward or back to select the gears by engaging dogs on th gears.

It is already hurt so I would put my foot on the prop and turn the flywheel with the engine in gear and see if you can determine where the problem is, if it is a stripped drive shaft it should click up on top if it is in the lower it will be down there but you should be able to at least figure out where the problem is.

If it won't go into gear disconnect the shifter under the cowl and try shifting by hand, rep[ort bakc what you find and I woudl do all this by hand, starting the engine could really increase the damage.

 

[F_R]

Re: stripped drive coupler??

Does it PUMP WATER?? If it does, the drive shaft is turning.

If it pumps, and no drive at all, does it shift to reverse? In no reverse OR forward, the shift linkage has a problem.

"prop turns" doesn't mean a thing. It would turn even in neutral.

 

[1946Zephyr]

Re: stripped drive coupler??

Yea, just pull that little obround plate on the side of the midsection and you will see your shift rod. Go through all the gears and look inside that hole to make sure the shift rod is moving. Sometimes the shift rod coupler can loose a shift rod then you're stuck in gear

 

[Chris1956]

Re: stripped drive coupler??

I knew a guy who's 90HP Johnny broke it's driveshaft, and he didn't even hit anything.

 

[nice-diver]

Re: stripped drive coupler??

thank you for the quick replys.

the tattle tale water stream works...so its not the coupler...yeah

we will try to work on it monday

his wife brought out the electric motor and we motored 1.6 miles back to the dock. we ran the motor to keep the battery charged and run the new side scanner.

thank you

 

[1946Zephyr]

Re: stripped drive coupler??

Well, if the motor is pumping water, that means your drive shaft is intact. Your shift rod coupler could have came undone though. You may likely have to drop the skeg half and look inside too.

 

[wilde1j]

Re: stripped drive coupler??

DS could be broken just below the water pump. I've seen that a few times where the DS broke just below the pump wear plate, so it pumped water, but no motion to the gear case.

Each case I saw looked like the DS had a casting/forging flaw, since a lot of the break surface was discolored from corrosion and only about 25% of the metal was a clean, new break.

 

[F_R]

Re: stripped drive coupler??

There is no point in just keeping on guessing. Remove the gearcase from the motor, and if you haven't found the problem by then, it will have to come apart.

BTW, drive shafts break because the housing is bent, causing the shaft to bend back and forth with every revolution. Replacing the shaft without checking the case is foolish.

 

[1946Zephyr]

Re: stripped drive coupler??

Oh yea, I totally agree. That's why I suggested checking the shift rod, through the access hole first and then pulling the skeg off and looking inside. There's a safe bet that something snapped inside, but may as well start with the easy stuff first. I have found a few bad cases in my day that would cause this.

 

[nice-diver]

Re: stripped drive coupler??

BROKE AT THE PINION GEAR

clean 100%silver break. its been apart before, so maybe the blue silicone was thicker on one side. found shafts on ebay and then found a long one for 50 plus shipping. He is thinking about making it short shaft. $200 in parts or start using my extra 40hp.

the motor is a 1977; 25hp. (my repair manual is for 80-95 or so) his gear case is two piece like a 28hp...why??

thanks for the help

 

[boobie]

Re: stripped drive coupler??

A clean break usually indicates a high impact. On a bent g/c, the upper splines on the d/s usually break or wear off.

 

[1946Zephyr]

Re: stripped drive coupler??

Oh boy. It broke above the pinion gear? Or did the splines break off?

 

[nice-diver]

Re: stripped drive coupler??

splines are all intact, broke 1/8th inch or so above pinion splines

he just bought the boat/motor last month. we've had it out four times with no incidents, and no rough housing with it. its pushing a 15' zodiac dive raft...the horse shoe kind of soft bottom inflatable

 

[wilde1j]

Re: stripped drive coupler??

Could have been from an impact before the purchase, but didn't break immediately.

 

[boobie]

Re: stripped drive coupler??

Agreed X 2.