Motor quit pulling

[big_o_tom]

1995 mercury promax , OG205338. Put a water pump in it, turned the flywheel to line up drive shaft splines, motor went into gear in forward and reverse.
Currently on the water being towed in by a pontoon boat. Put the boat in the water, it started fine, shifted fine, had water pressure, idled out past the no wake sign and took off.
I'm gonna guess I went about 6 miles down the lake, was running 55 and it revved up. I came to a stop to check it out. In neutral I can spin the prop then when it put in gear I can't spin the prop. When I start the motor and put it in gear the prop doesn't even try to spin. What is it? I figured if the gears are stripped I should be able to spin the prop in forward or reverse but I cant. Don't make sense to me.

[rgsauger]

Check the shifter shaft when you get out of the water. Have somebody move the shifter forward and reverse and you get back there and see if it is rotating the shaft input for the lower unit.

[big_o_tom]

Yes it is.

[jbh3]

Does your prop have a pressed in hub? Sounds like a possible spun hub if everything else seems to be working OK.

[big_o_tom]

No it's the flow torque one. With the motor off and in neutral the prop spins freely, put it in gear and the prop stops. Start the motor and put in gear and the prop doesn't even attempt to spin.

[rgsauger]

Wow, no friggin’ clue. Please post when you figure out what it was

if you turn the fly wheel by hand, does the prop respond accordingly?

[Merc2.4]

Sounds like broke the drive shaft in the unit

Last one broke on me. Was headed down river and motor revved waayy up.

[big_o_tom]

Sounds like broke the drive shaft in the unit

Last one broke on me. Was headed down river and motor revved waayy up.

Ok, so that would explain why the motor (when running) doesn't turn the prop. But doesn't explain why when put into gear (motor not running) the prop won't turn.
I'm gonna pull the lower unit today and maybe something will be obvious.

[JOE54]

if drive shft breaks pinion doesn't turn , when in gear clutch is engaged in fwd or rev if something failed internal gears will still not turn , your trying to move gears make sense ?????

[big_o_tom]

Pulled the lower off and the drive shaft looks good, splines look good, put it in a tank of water and turned the drive shaft and the pump pumped water.
Then I started trying to put it in gear and turn the prop and it didn't work. Last week when I changed the water pump I spun the prop in gear to see what the gear ratio was and everything was smooth. Today I can't spin the prop, so it's definitely something in the gear box.
I guess it's time to start looking for a sportsmaster!

[lpugh]

Negative on the sportsmaster unless your boat can exceed 80 MPH
Did you drain the oil for inspection?

[big_o_tom]

I've had my boat 85, so I'm right at the point of needing one anyway. Tore into the lower today. I have a busted pinion gear and the bearing that is right above the pinion is busted also.

[lpugh]

You sure are and a little past

[JOE54]

I have a busted pinion gear and the bearing that is right above the pinion is busted also.

and now you understand how D/S can rotate without moving gearas or propshaft

[big_o_tom]

I am very familiar with drive shafts and gears on 4x4's. I have installed and set up a few. I have also broken a few. When they break you can spin the wheels all you want and the drive shaft ain't gonna turn. I guess when the motor was running the pinion gear was spread apart causing the splines not to mesh, then when I would turn the prop by hand the rotation of the ring gear kinda made the pinion gear close back up some and grab hold to the driveshaft. Any how...I got to get a lower unit.

[JOE54]

yes sir, torque mqsters and sportmasters are more durable running at an elevated height (better berngs shafts and carriers ) folks do get away with running standard coned cases but usualy have problems in the end fro stressed parts good luck big O

[big_o_tom]

I'm looking at a sportmaster right now, it has the same gear ratio as my lower unit that just broke. Does that mean the gears are the same? Or are they a little more heavy duty?

[silverbullet02]

I’ve seen standard cases with a cone run for years and years trouble free. I’ve seen sportmasters lose their guts. It’s all a crap shoot with these things. On an allison like he has he needs to get that prop up. He’s right about searching for a sportmaster, overall the most trouble free gearcase *generally speaking*.

The one that just broke on him is a 4 hole cle with a cone added, which has the “good internals” in it.

It’s all part of the game. Good luck finding a case, they come along pretty regularly when you aren’t looking for one, lol!

[silverbullet02]

I'm looking at a sportmaster right now, it has the same gear ratio as my lower unit that just broke. Does that mean the gears are the same? Or are they a little more heavy duty?

Should be the same inside, I think the big difference is the 2nd driveshaft bearing on the sporty of I remember right. Only thing to look out for is rusty shafts. They ran stainless shafts which don’t corrode too bad and they also ran some “stronger” shafts with a different makeup which rust really bad and rot out. If the shaft is rusty I’d do a thorough inspection on it. Could be trouble.

[Merc2.4]

Ok, so that would explain why the motor (when running) doesn't turn the prop. But doesn't explain why when put into gear (motor not running) the prop won't turn.
I'm gonna pull the lower unit today and maybe something will be obvious.

Everytime I've seen drive shaft break was rite above the pinion, which u wont b able to see because bearing under water pump base plate , breaks below that bearing