Bravo drive. All fine.. Then grinding. Now nothing.

[BajabossJD]

Hello All..

Sitting in the ICW of beautiful Fort Lauderdale. Engine was acting funnig.. Changed fuel filter at gas dock and things got better. Tried to hop up on plane and then a loud grinding came from the engine. Engine still runs fine, but the drive won't engage. I look and see the flywheel spinning the drive shaft in neutral, when I put it in gear.. ( all cables moving fine). I see the drive shaft slows way more than the flywheel. What te heck happened. No propulsion.


TowBoat Us on the way.

Thanks,

Joe

7.4 x bravo 1

 

[Don S]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

I see the drive shaft slows way more than the flywheel.

Sounds like you spun the rubber coupler. That may have happened due to a failed drive. Drain the gear lube and see if you have metal in the gear lube. The engine has to come out to replace the coupler

 

[BajabossJD]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Looks like I see some shavings by the flywheel. I think it's def the bushing on the flywheel. Any other way to tell if the drive is bad?

 

[Don S]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Looks like I see some shavings by the flywheel. I think it's def the bushing on the flywheel. Any other way to tell if the drive is bad?

Not in the water.

 

[BajabossJD]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Boats out now. Towboat got me.

 

[Don S]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Boats out now. Towboat got me.

Then pull the drive, drain the oil and check it. Turn the input shaft and prop shaft and see how it feels.

That's a start anyway.

 

[BajabossJD]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Engine starts fine. I engage the gear and the prop spins in fine in both forward and reverse. I'll drain the drive oil and take a look. I can also spin the prop just fine.

I could yank the engine to replace that bushing..but it's hell down in S Fla this summer. What am I looking at to have the engine pulled to replace that bushing on the flywheel?

Thanks,

Joe

 

[BajabossJD]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Am I looking at $500ish to have this job done? I am thinking I need a new drive shaft too.. As the splines are prob shot.



Thanks,
Joe

 

[muc]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Hi Joe,
While I understand your desire to know how much this problem is going to cost you, nobody here can answer that question.

The first problem is a coupler failure is a symptom and the cause of the failure must be diagnosed so it can be corrected and allow the new coupler to live a long life.

Some of the common causes are,
Lack of maintenance
Improper alignment
Excessive low speed operation

The next problem is accessibility to pull the engine and how much corrosion will have to be dealt with.

Than you have things that maybe should be done while the engine is out because on some boats the engine has to come out to do them. Things like a leaky engine rear main seal, starter, rear motor mounts and bell housing water hose. These items can be done when the engine is out for basically the cost of the parts so it might be in your best interest to do them now.

I recommend that you consider a steel splined coupler instead of the aluminum splined one that came stock with your engine --- they have proven to last much longer on the 7.4 engines.

I can give you some ballpark numbers.
MerCruiser steel coupler = $750.00
Yoke – engine end (what you called drive shaft) = $200.00
Average labor to R+R engine 7 to 10 hours

 

[BajabossJD]

Re: Bravo drive. All fine.. Then grinding. Now nothing.

Thanks a bunch for the information. Very odd problem to have while hanging around 600rpm in no wake zones. I'm gonna attempt to do these things myself.. That way I can take my time and clean up some things in there. I have done a bunch to this boat, and work on all my own cars. I am sure I can get it all apart. I guess I will know more when the engine is out. I am thinking it wasn't aligned properly when the engine was rebuillt last year ( or possibly bad engine mounts).

I think at this point, Alignment may be the part I leave to the pro. We have many mobile marine tech's down here..and I doubt the Pro Alignment would be more than an hour or so.

I will check back for tips during this R and R.

Thanks,

Joe