Broken Drive Shaft?!?!

[Geronimo36]

i hear ya. I was concerned of him not being able to find a lift high enough to clear the boat, especially if it's on a trailer. If he couldn't get the engine high enough without making special plans he could turn it or move it forward a little.

We've all been in a pinch! Last one I did like that was for a customer at 7 pm the night before a poker run. It was a 45' Sonic and in order to get the engine out we had to take the huge hatch off the back and no time... Disconnected the rams, had a Mexi hold it up, cotton on the forklift and me in the bilge. We got it done in about an hour to an hour and a half soup to nuts! That boat owner is now my boss for the past 9 yrs!

[Freeryd_99]

So, someone said they can get me the part i need for $300. Is that about right? What else should i do while i've got this motor out? There's nearly 600hrs on it, and i don't think much has been done ever. (i'm the 2nd owner) List them off guys!

[Airpacker]

600hrs? One word. Rebuild.

[Ratickle]

600hrs? One word. Rebuild.

I'm with Sean if you already have it out.

However, I'd run a comp and leakdown test, and if you're close to good, wait till winter......

[Geronimo36]

Same here....that's alot of hours. At minimum have a rebuild/replacement budgeted in at the end of the season.

[MOBILEMERCMAN]

Same here....that's alot of hours. At minimum have a rebuild/replacement budgeted in at the end of the season.

I'm with Frank. No sense disabling it now. Budget for end of season. And change the other coupler too.

[ROGUE]

I agree it's probably the coupler. BUT I would try another prop to make sure there wasn't a problem with the new hub installed. Chances are very slim but I would want to know 100% before I yanked the motor. I've had couplers and prop hubs go and they acted identical. Could idle but applied throttle and free revved like in neutral.

I second this. Having blown prop hubs and couplers, this sounds like a prop hub, when I had a coupler let go I had nothing, no propulsion at all. Did you find signs of burnt or dislodged rubber behind the motor?

[phragle]

bellows and gimble bearings..

[Ryan8886]

I second this. Having blown prop hubs and couplers, this sounds like a prop hub, when I had a coupler let go I had nothing, no propulsion at all. Did you find signs of burnt or dislodged rubber behind the motor?

Eh....I had 2 almost fried couplers and no symptoms...my wrench said I was one hole shot from completely blowing them out. After seeing them, I was convinced he wasn't BS'ing me. Sure sounds like couplers to me.

As for what to do while the motors are pulled....with 600 hrs the minimum I would do is fresh starters....how much would it su@k to get it all back together just to hear the dreaded....click?

[Tinkerer]

It isn't lack of grease that blows couplers its lack of alignment.

Get an alignment tool - your engine is WAY off.

[MOBILEMERCMAN]

It isn't lack of grease that blows couplers its lack of alignment.

Get an alignment tool - your engine is WAY off.

Bad alignment takes out the rubber part. Lack of grease takes out the Aluminum spline

[Geronimo36]

I'm with Jimmy....

Steel shaft + aluminum splines + no grease = bad coupler.

Regardless though, he should re-check the alignment when re-installing the engine. I like the starter idea as well.

[Blue Thunder]

It isn't lack of grease that blows couplers its lack of alignment.

Get an alignment tool - your engine is WAY off.

I agree with tinker... I have taken the splines out of several couplers due to misaligned engines. Never blown the rubber out ever.

[MOBILEMERCMAN]

I agree with tinker... I have taken the splines out of several couplers due to misaligned engines. Never blown the rubber out ever.

There must have been an error in your analysis.

[Blue Thunder]

Could be but I don't think so. When I bought the boat the guy gave me an alignment tool he made. I blew the splines out of several couplers on both engines and the alignment always showed good with the tool. Finally it occured to me that this tool might be the problem. I ordered a merc alignment tool and the alignment was way off on both engines. After spending some time adjusting the alignment properly I have never wiped out the splines on another coupler. I even ran one coupler with pointy splines that was run with the out of alignment situation and never took that out after the engines were aligned properly.

Theres my analysis mobilemercman, lets hear your supporting analysis.

[MOBILEMERCMAN]

All I can say is I base my opinion on over 25 years of service on countless boats. If your splines are dry they will fail aligned or not.

[Geronimo36]

In all honesty I've seen both... Most spun hubs I saw were on ski boats. More often than not spline failure was due to lack of grease or improper grease but once I did see the spline go away from alignment but it was rare. There was even a boat that I used to work on with offshore mounts that the alignment was so bad you had to force the drive on by kicking it or using a "persuasion block" and it never wiped a coupler.

At the end of the day what will tell us the story is how wet/dry the coupler is with grease and what kind of grease was used. If everything is wet with good spline grease and the splines are wasted I'd point towards alignment.

Regardless he should check the alignment when he puts the engines back in especially since it sounds like he has stock mounts.

[Tinkerer]

So - did it take out the splines or the rubber?
If it took out the splines the boat wouldn't move at idle.
If it took out the rubber the boat would move at idle but no more than that.
I have taken out brand new couplers that were properly greased ( rubber part ) in less than 30 minutes due to an allignment problem that the stock merc. tool didn't show as out of alignment. I have since modified mine to show if the rear mounts are sagged.
How many of you check to see that the tool is paralell to the bottom of the boat???

[Tinkerer]

If your splines are dry - yes the splines WILL fail but it WILL take a long time to do so.
If your engine is out of alignment the life is measured in hours.

And that comes from 31 years of working on HP boats with lots of HP.

[MOBILEMERCMAN]

Not sure what parallel to the bottom has to do with it. That has more to do with transom angle than alignment. The alignment on a alpha or bravo is to position the coupler to the gimble bearing. The tool wont check the condition of the outer pieces like the gimble ring. As the gimble ring settles it will mis align everything after the gimble bearing. That will be contribute to coupler and other upper drive failures.

On drives with transmissions the alignment is more inclusive. It aligns the output shaft to the bellhousing. As the gimble ring settles in these the misalignment is more easily recognized.

My merc tool is old and has never mislead me.