Disaster has struck! Give me your opinions!

[Speakrdude]

So, repowering 96 Maxum 3200SCR (big boat!) Both blocks (7.4L Gen V's 4BBL) froze and broke, bought it that way. No PO info available. Drives (Bravo III's)
Removed the drives, cleaned the surfaces, painted etc.
Rebuilt (completely) both gimbal housings.
U-joints looked/felt fine. Greased all.
Everything spins good, shifts good etc.
Gimbal bearings felt good, reused, greased.
Installed two freshly built 7.4L's. (used alignment tool. good to go, both drives)
Broke in port engine yesterday, in her slip. (first time to run) 2000 rpms, min 30 minutes. Life is good. Adjusted timing, idle, shifted drive, forward/reverse, all good.
Broke in Stbrd engine today, same process, all is good. shifted forward/reverse, yada yada

AND THEN,

I decided to check port engine again. Started right up, then rrrrrrrrrrrr, sounded like a chainsaw in the fan belt.
Went to inspect, and discovered the drive shaft was not spinning and the hub had stripped itself out. (That was the rrrrrrr sound)

So, what do you think?

A. Bad hub. (that's a given)
B. frozen drive, causing the hub to strip?

Have to pull drive first, so I will figure that one out right away.

 

[thumpar]

By hub I am guessing that you mean coupler. Put the drive in gear (not running) and see if you can spin the prop. It will take some force but if it spins it is not the drive. Usually when the splines go out it is lack of grease.

 

[Speakrdude]

Yes, I meant coupler. just greased the lill bagger when I reassembled, just on the splines though. When I cleaned off the drive shaft prior to reinstalling, I did find long "shards" of metal down in the splines. I suppose that was the tell-tell sign. Hopefully, that's all it is. Regardless, out she comes......

 

[Bondo]

When I cleaned off the drive shaft prior to reinstalling, I did find long "shards" of metal down in the splines. I suppose that was the tell-tell sign.

Ayuh,..... That's when ya shoulda looked to see how flat, rather than pointy the splines were,.....

Sounds like it was beat from the get-go,...

 

[tpenfield]

Ouch, . . . could'da saved a bunch of time replacing the coupler(s) if you found the metal shards ahead of time. The couplers for the 7.4's are a bit pricey, so hopefully you can find one at a decent price.

 

[Fun Times]

I'm sounding like a broken record here but since you just had the couplers out/off, be sure to check your run-out just in case you have a potential problem as well. You should be able to find a few topics inside this web search. http://www.bing.com/search?q=Mercrui...IE10TR&pc=DCJB

And here's the correct way to mount your coupler to the flywheel now, Service Bulletin - Marine Mechanic

 

[Speakrdude]

Excellent article on "How to install coupler", service bulletin! I would never have thought to do that! Hopefully the Sierra coupler I bought, will have those tapered bolts. If not, I will find. Not exactly clear on checking the run out. What are we checking? Coupler, crank, flywheel, all of the above?
As always, Thanks for all the GREAT advise!

 

[alldodge]

Broke in port engine yesterday, in her slip.

Running the engine in the slip at 2000rpm (neutral) and the coupler gave up the ghost. I think there is a drive problem

 

[Speakrdude]

Drive seemed to turn normal and freely when installed. After break in period, at idle, shifted into forward / reverse several times, no problems.
The next day, when I started it, is when the event happened. While cranking only, the drives spins with the coupler as normal. Only slips/stripped when the engine is running.

 

[Speakrdude]

So, tomorrow am, we are pulling the boat. Pulling the drive, and hopefully, lifting and sliding the engine far enough forward to change the coupler. The new coupler is a sierra and they don't subscribe to the Mercruiser method of tapered bolts to align. Anything I should do differently with that?
Also, anything I should check with the drive, other than verifying it turns freely in neutral, while off the boat?

Thanks

 

[alldodge]

Your saying the coupler does not have the tapered holes?

The bolts to secure the coupler should be tapered, are they?

 

[Speakrdude]

That I couldn't tell you. They are sealed in a package. The new Sierra coupler may have tapered holes. I thought, from the SB I read, that Mercruiser included 3 tapered bolts that you use to install in every other hole. Once they are in, the couple is aligned, and you install/torque the remaining bolts, and then remove the tapered bolts to install the remaining bolts.

 

[bruceb58]

I would only use the OEM couplers.

 

[alldodge]

Guess center it the best you can

 

[Faztbullet]

Make sure you check alignment of gimbal to coupler with alignment tool(donkey d**k)

 

[Speakrdude]

Done! (kind of) New coupler does in fact, come with bolts that precisely fit the hole, thereby aligning quite nicely.
reinstalled engine. took my time with the alignment process. Went ahead and pulled the strbd drive to reroute the shift cable, (7.4L very specific cable route. ask me how I know!) and realigned that engine as well.
Greased (with spline grease) both shafts extremely well (u-joints too, since I was in there) reinstalled drives, pumped the couplers with grease. (Can these things be any harder to get too!!!)
Put boat back into water after a long 7 hours of work. Fired up strb engine. Port engine will not fire at all, only turn over. (must have knocked loose a wire) O'well, use port engine, get her back to her slip, deal with it later.
WAIT! Strb engine overheating now! Must have air locked from pulling her out and not priming the strainer.
Damn. Now I need a tow to her slip. LONG DAY!
Back in her slip now, resting up. Razorbacks win their homecoming game (blowout)
Made it home to start the 3rd quarter.
Sunday is a new fresh day. Hopefully, no damage was done to the strb overheat issue, with the exception of, more than likely, the impeller.

 

[alldodge]

Hope there is no harm and maybe more simple, like the belt broke

 

[Speakrdude]

Seems like strbd engine simply had an air lock. Checked pump, so far so good.
Port engine, probably flooded from all the moving around. Fired right up this morning, but no water flow. Took raw water pump apart, 0 vanes on the impeller!
Went looking, found all the parts. Will install new impeller and housing tomorrow. Should be good to go!
Ya never know..........