Engine drive coupler

"Hi every one. I am going to

"Hi every one. I am going to change the gimbal bearing on my 1973 165hp Mercruiser. I was thinking that it would be a good idea to change the engine drive coupler at the same time. Can this be done with out taking out the engine?

Thanks,
Vintage."

No

No

"allan's short answer is c

"allan's short answer is correct.
The bellhousing must come off to change the coupler, and since the bellhousing is what supports the rear of the engine off the transom assembly, the engine must come out to do the job.
No big deal if you have a good hoist.

Rod"

"Eric, You should inspect your

"Eric, You should inspect your old coupler while you are doing the gymbal bearing, take a good lite and look at your coupler splines thru the transom. you should see wide splines. Not narrow and pointed splines. Then decide if you need to pull the engine to do the coupler.
hope this helps some."

Thanks for the help Allan. Si

Thanks for the help Allan. Since it sound like you know quite a bit about this....My original plan was to change the gimbal bearing this year because of excess noise. After reading some "posts" about changing the gimbal bearing in looks like I may have to remove the engine anyway to help get the out drive off by pounding on the drive shaft. The deal with the drive coupling is this...when the boat is put under load of almost any amount in "slips in to neutral" or so to speak. I was origially thinking that the hub in the prop was bad. Which may or may not be correct. What I do know is that when I put the engine in the last time I did not "index" it. So I am thinking that the engine drive hub may have been damage due to my hastiness. I also understand that the engine drive hub has shock absorbing abilities? Is this correct?

Thanks for the help.

Eric<><

"Eric, do one step at a time.

"Eric, do one step at a time. remove the drive and see what you find.Gymbal bearings dont go bad, unless they get wet. either from inside the boat with flooded engine compartment or bad u-joint bellows, the water rusts the bearing making it loud.
Pull the drive and check things from there.
6 nuts on bellhousing, 2 nuts on drive trim rams (control in full forward ghear). the drive will come off without pulling the engine. sometimes I have to wedge them off usine the trimrams and a block of wood between the topcap of the drive and the transomshield.
Normaly I can just lift the drive aganst the wood block by hand, but if it doesn't come loose after a few good upward gerks I'll reconect the trimrams and use the up button to pop it loose.
Be aware that the trimrams have obout 2500 psi on the up side and can snap the gymbay ring if you are not careful.
good luck post if you have more ?s I'll work with you."

"Yes, I flooded the engine com

"Yes, I flooded the engine compartment, and I mean really full for a good while and that was 16 years or so ago. The gimbal is growling pretty bad. I'll yank the out drive first. What about the drive hub being shock absorbing?

Eric,<><"

"The coupler is mounted in rub

"The coupler is mounted in rubber, when it slips you will smell burnt rubber around the enging,sometimes smoke too.when the coupler strips its splines it is from no grease or not properly alinged.
Have you checked your prop hub?Mark it after you check it, to see if it has spun the next time you remove it.
Check your u-joints also.Grease them, if they spit out rusty muck, you should replace them also.
I'l check back to see if you have more ?s
L8R"

So I pulled the out drive off

So I pulled the out drive off and it came off fairly easy. The gimbal bearing is definately toast. Peered into the female splined on the drive coupler and they are all pointed. Looks I will be pulling the engine. The gimbal bearing came out easy....once I removed the snap ring out.................

Eric

"Eric - Sounds like you have a

"Eric - Sounds like you have a prop hub failure and not an engine coupler. In failure mode, a coupler will not act like a slipping clutch as a prop hub will. Take the prop hub insert out and look for hair line cracks (if you have a replacable hub). As mentioned above, when a coupler lets go, it makes a burnt rubber smell and its done.... Its usually the rubber that splits with the hub and not the splines.}"

Check your front engine mount

Check your front engine mount bases for rot.

I believe the slipping is the

I believe the slipping is the prop hub too. But the drive hub is pretty funky looking with all the pointed splines. I was going to tidy up the front mount holes as they are some what rotted. Larger lag bolts doesn't seem to be makin' it.

Eric

"Eric:

If the wood is wet,

"Eric:

If the wood is wet, you need to replace the bases with yellow pine or hardwood blocks. Cut the tops of the bases off horizontially like taking off a lid. Dig out all the wood and cut you new blocks to fit loose. Laminate several pieces of 2"X6" lumber by glueing w/EPOXY. Build a dam around the bottom of each base so no L&L Epoxy can run out. Pour some L&L Epoxy inside each base opening and slide in the new bases. Pour the remaining L&L around the sides and let it set up; may take a few days.

Once it is set up HARD and you are ready to set your engine mounts, pre-drill the mount holes, run your lag screws in them and then remove them.
Pour some CPES in each hole and let it soak into the wood and dry a few days. They'll never rot again. http://www.rotdoc.com/products/cpes.html"

Thanks for the tips Guy. It s

Thanks for the tips Guy. It sound like the repair you described is a little different thent mine. The bottom of my bilge(?) is flat and the engine mount sit right down flat on the bilge. But the procedure should be largely the same: cut the bad stuff out and epoxy the good stuff in. What is the best epoxy? And what kind of hardwood do you recommend?

Eric

"Eric:

Yellow pine is hard

"Eric:

Yellow pine is hard enough but may not be available in the size you want in a small quantity. That's why I suggeted laminating 2"X6" pieces and clamping them together. HAVE EVERYTHING ready to go before you mix the epoxy. You'll need some acetone for cleanup--watch out for the toxic fumes! Scuff the bilge and degrease it before epoxying.

Epoxy comes in quick set and slow set and also cold or warm weather. L&L (Laminating & Leveling) epoxy is good for fiberglassing on flat surfaces and filling voids; dams are needed or it runs out--stuff sets very SLOWLY but hard as a rock. It is also good for making epoxy/sawdust puddy to fill large voids. I got some waste sawdust from the lumberyard and used the wife's flour sifter to remove the big chunks. Just mix it together until you get the consistency you want and trowel in in place or tamp it inside the engine mt. base.

I've used the Rot Dr.'s products and they work well. There are other brands for less that work just as well. Google CPES to find them. I have an epoxy mfg. 30 miles from me that sold me the stuff by the gallons (10) at wholesale because he was interested in my project. His set in 30 minutes. Mix small amts. and keep the container inside another one packed w/ice when it's warm. For quick setting type, keep stirring it or the catalyst will begin to set on you quickly. Remember, use epoxy instead of the other cheap crap."

"im almost ready to pull my 3

"im almost ready to pull my 3 liter engine, but for one problem. i don't know how to disconnect the coupler from the fly wheel.it looks like theres a metal cover over the coupler. the flywheel cover looks like one piece. How do you get to the nuts on the coupler? Please help."

"thomas, your really better of

"thomas, your really better off starting a new thread.
remove the drive, pull the engine, remove flywheel dust cover, remove flywheel cover, remove coupler bolts."