Engine Runs Fine, Prop only turns at about idle speed

During my last outing I was running at cruise with some friends, all was well so I put a few more RPM's to her (1976 Bayliner 302/ 888 outdrive) and lost forward thrust, except at idle. I was loosing the Gimbal bearing too, so we got towed in and hauled it home. I didn't check reverse (it just occured to me now that I should have tried that). I ran it on the hose at home to rinse out the salt. There is no or little noise, outdrive oil appeared fine (some fine metal shaving on the vent magnet). I can put it in gear and the prop won't turn against the engine.

I removed the outdrive today... gimball is bad.. water got in there from somewhere (it's a new bellows); u-joint seems fine..

Q. Could the drive assembly allow slippage?
Q. Is there some linkage on the engine side of this that could be a problem?
Q. How can I troubleshoot if it is fwd or rvs gears?
Can I close my eyes and have it go away?

Thanks for reading my post.. I would appreciate all comments!

Re: Engine Runs Fine, Prop only turns at about idle speed

The rubber hub is probably spun on the prop. Have it replaced by a prop shop, or replace the prop with a new one.
Mark the inner hub and the prop hub. Run the prop under load and see if the marks have moved after you remove the prop.

Re: Engine Runs Fine, Prop only turns at about idle speed

Was there water present in the u joint bellows when you removed the drive?
Don is right about the hub....
I suggest that you get your prop rehubbed & buy a spare as well......JK

Re: Engine Runs Fine, Prop only turns at about idle speed

Spare prop is like a spare tire. Don't leave home without one.

I also think its a spun hub.:/

Re: Engine Runs Fine, Prop only turns at about idle speed

Haut said:

Was there water present in the u joint bellows when you removed the drive?
Don is right about the hub....
I suggest that you get your prop rehubbed & buy a spare as well......JK

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Yes, there was water in the bellows! There shouldn't be... as it is a new bellows. And looking in there, I would think that the gimbal bearing needs to be replaced.. Is there an inexpensive way to pull it out without the $250 tool shown on mercrusier parts sites. Also, would a spun hub smoke up the engine compartment? There are times when cruising that I get a smell of oil, (not engine oil, but more like outdrive oil). Any thoughts or suggestions.

Thanks

Re: Engine Runs Fine, Prop only turns at about idle speed

I have a spare prop, thanks... I haven't really abused this, so if the hub is spun... I am amazed at how easily it spun. The prop has three seasons on it.. tubing, and an annual outing on the Puget Sound. So what would cause smoke to come out of the engine compartment toward the stern when this event took place? Could it be a different matter entirely, as I also began to experience an out of balance type vibration at the same time. So to prevent further damage, we shut her down. And, ever since I owned this boat, when I am cruising I will often get a good wiff of gear oil smell,

Thanks for any and all replies...

Oh, and I should have done the prop thing before I removed the outdrive huh? :/

Re: Engine Runs Fine, Prop only turns at about idle speed

It sounds like you may have more than one problem......
If you had salt water in your bellows that is bad news.....
A spun hub would not put smoke in the engine compartment......
A bad engine coupler would though....
Did it over heat?
I would have tried the spare prop before I removed the drive, just to eliminate the possibility of a spun hub, because it is something you can't see through visual inspection.......
If you smoked the coupler, I would suspect bad alignment, do you have an alignment tool?....
Where in WA. are you, btw?......JK

Re: Engine Runs Fine, Prop only turns at about idle speed

Haut said:

It sounds like you may have more than one problem......
If you had salt water in your bellows that is bad news.....
A spun hub would not put smoke in the engine compartment......
A bad engine coupler would though....
Did it over heat?
I would have tried the spare prop before I removed the drive, just to eliminate the possibility of a spun hub, because it is something you can't see through visual inspection.......
If you smoked the coupler, I would suspect bad alignment, do you have an alignment tool?....
Where in WA. are you, btw?......JK

Click to expand...

Re: Engine Runs Fine, Prop only turns at about idle speed

Haut said:

It sounds like you may have more than one problem......
If you had salt water in your bellows that is bad news.....
A spun hub would not put smoke in the engine compartment......
A bad engine coupler would though....
Did it over heat?
I would have tried the spare prop before I removed the drive, just to eliminate the possibility of a spun hub, because it is something you can't see through visual inspection.......
If you smoked the coupler, I would suspect bad alignment, do you have an alignment tool?....
Where in WA. are you, btw?......JK

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Opps, I replied without anything...

1. I have wondered about the engine coupler, but I haven't found any significant information about them.. my manual doesn't go into that..
2. Yes, it's not the first time I have had water there.. purchased it with bad bellows.. live and learn.. could have sunk! Now I am sinking money into it..
3. I don't think the engine has overheated.. temp gauge is not working as best I can tell.
4. I am just over the hill in Cle Elum.. without an alignment tool.

So, should I repair and keep it, or junk it and find another hole to pour money into? ;-)

Re: Engine Runs Fine, Prop only turns at about idle speed

Haut said:

Was there water present in the u joint bellows when you removed the drive?
Don is right about the hub....
I suggest that you get your prop rehubbed & buy a spare as well......JK

Click to expand...

Tacoma Prop has hubs for $37... I could buy one to use or keep as a spare when/ if needed. Thanks..

Re: Engine Runs Fine, Prop only turns at about idle speed

Only you can answer that.....
How much do you like the boat & how much time/money do you have to invest?
The amount of work that needs to be done can only be determined through a series of test procedures.....
First, I would look at the splines on the input shaft for unusual signs of wear & use a flashlight to look through the gimble bearing at the splines on the coupler itself....
Then I would fix the temp. gauge & run it on the muffs & see if it overheats.....
If the drive will not, or is extremely hard to go back on,
I would check the alignment which should be done anyway......
This will tell you if your alignment is off.....
If it is, then you may have either bad mounts or rotted stringers.....
If it goes on OK, & alignment checks out, I would move on to the leaking bellows/gimbal bearing issue.....
If the coupler/alignment is bad & you have rotten stringers, you may not to want waste your time going any further....
The engine will have to come out to replace the coupler..
Anyway, this is where I would start......JK

Re: Engine Runs Fine, Prop only turns at about idle speed

When I said get a spare, I meant get a spare prop, not just the hub....
The hub is something that you can't do yourself on older props....
Get it rehubbed at a prop shop or just buy a new one....
If it not a stainless, I wouldn't waste my time rehubbing, I would go new.....JMHO.......JK

Re: Engine Runs Fine, Prop only turns at about idle speed

The smoke in the engine compartment would lead me to believe the coupler went. Take HM's advice above & check the operating temp closely.

Re: Engine Runs Fine, Prop only turns at about idle speed

I'm going to agree with those that said that It's the coupler, based on the smell and smoke from the engine compartment at the time of the failure, and the subsequent vibration. Since this means you will be pulling the engine, it might be worthwhile to absolutely eliminate the possibility that it is the prop hub, by the match-mark method described above, or by running one you know is good. If it's not the prop, it's the coupler.

Re: Engine Runs Fine, Prop only turns at about idle speed

Well, the engine is finally out.. well in the boat on a piece of plywood for working on it.. and guess what? That coupler was toast! I think replacing it from here is not a big deal.. just get the check book out... and some wrenches. I am only disappointed that there is not much information about this in my book. (Seloc)

I am guessing the previous owner put this engine in himself and tried to line up the engine without that Mercruiser $200 tool. I got four seasons out of it.. needs a set of manifolds while I got it out..

Any help in the coupler would be appreciated... and if you have a good line on 888 / 302 manifolds

Thanks

Re: Engine Runs Fine, Prop only turns at about idle speed

am guessing the previous owner put this engine in himself and tried to line up the engine without that Mercruiser $200 tool

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that could be true. but it could be true yer stringers are bad and thats why the engine was out of alignment and ate yer coupler. check out what the motor mounts to real good. i aint seen to many but, it seems that most are mounted to, not to much wood...that could be soft or rotting. my 75 trisonic frount motor mount was mounted to a piece of plywood, (that was rotton) and i seen a searay that had the front motor mount screwed down to a 2X4 that was dust. both these were IL engines, yer v8 i think is problably mounted to the stringers i would guess, which may offer more to bolt a motor mount down to, but i'd check em out good before procedeing. ya gotta have something to mount yer new parts down too......food for thought before ya spend yer bread on parts.....

Re: Engine Runs Fine, Prop only turns at about idle speed

I am guessing the previous owner put this engine in himself and tried to line up the engine without that Mercruiser $200 tool.

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Your problem could also be bad rear motor mounts. On Mercruisers, rear mount failures are the main cause of the engine going out of alignment. Happens all the time.
That is one of the reasons the alignment is checked yearly (usually during winterization when the drive is removed for service).

You mentioned that $200 tool, if you look around, that tool can be had from ebay for 150 less, new aftermarket ones are only 75.

Re: Engine Runs Fine, Prop only turns at about idle speed

Your problem could also be bad rear motor mounts. On Mercruisers, rear mount failures are the main cause of the engine going out of alignment. Happens all the time.

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That's a pretty solid item here.. how would I check? Spacers? Shims? What would be a primary indicator .. if I remember right, it's bolted to the transom.. is part of the Transom plate?

As for Mercrusiser tools, I am considering putting all the parts in place.. and then taking the boat to Inland Boats to have it put back together.. should be just a labor charge.. a few parts if needed. Or I still may part this out..
I really like a Glasply in Bellevue.. but I haven't gone to see it.. only concern is it's age.. but I should have thought of that when I bought mine!

Later

Re: Engine Runs Fine, Prop only turns at about idle speed

i'd check em out good before procedeing. ya gotta have something to mount yer new parts down too......food for thought before ya spend yer bread on parts.....

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Yeah.. one thing Bayliner did with it's 70's boats was use a lot of fiberglass. The stringers are very beefed up, don't make an hollow sound when tapped on with a hammer.. I can't even see wood in there, but there must be.. I don't know how else to check these without damaging them. What would you recommend?

Blu

Re: Engine Runs Fine, Prop only turns at about idle speed

I don't know how else to check these without damaging them

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yer hammer idea seems good to me. if ya can't see any wood, anywhere. i could see wood on mine, as someone else had been engineerin on my boat and that seemed like a clue. i looked into the hole that ran leagth wise down the center of the boat and exits into the bilge for water draining from the front of the boat. could see dark wood in the hole, + felt in the hole on the backside and was soft and wet with no fiberglass on the back side that i could feel. another clue that i had bad wood was my ft. motor mount bolt holes. the old bolts came out way to easy(this was my 1st clue). my lag bolts themselves were not SS bolts. so the fact that the screw threads where rusted out where they were in the board was suspisious. i inspected those bolt holes every which way i could think of. looked, probed with an ice pick, and like ya said, finially with a destructive method. a drill bit. the drill bit reveal much. dark brown, wet, dust. i also tried running a new lag bolt in my motor mount bolt holes to see if i could torque it up like i thought i should with a new bolt. i couldn't. my suspisions were up enough by that point to make a bigger hole and everything was confirmed...... rot......if i would not have had dusty water, but real wood whith my 1st drill bit. i would have had to repair that hole but would have been happy to see wood instead of rot..... that's was my method of maddness to find out. perhaps there are other ways too......