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-   -   4 Engine Coupler Failures, Why??? (https://www.offshoreonly.com/forums/general-boating-discussion/159544-4-engine-coupler-failures-why.html)

Edward R. Cozzi 05-30-2007 07:49 AM

If he's a new boater, does he know you must trim the units down before taking off?

I've also seen the bellhousing mounts collapsed and causing the alignment issue.

Panther 05-30-2007 08:08 AM

If the mechanic who replaced the couplers "forgot" to put spine grease on the input shafts and a light coating inside the new coupler it will wear out faster than you can shake a stick because of the steel shaft and aluminum housing. :(

txriverrat2001 05-30-2007 08:32 AM

is he sure it's the couplers? Every one I've seen spin the hub in the rubber will puke the rubber all in the engine compartment - it's obvious what's going on - stinks like hell. If the splines get ate up - it's a done deal. No waiting 5 minutes then getting on it again.

Alignment is critical - just because the bar will go in - doesn't mean it's right. You should be able to push it in with one finger and pull it out just as easy. The new ones are tempermental as the metal inside the coupler is not just one solid tube. I've always ran the alignment tool in the coupler before mouting on the engine to "set" the splines.

A bad transom will eat couplers - but again.... once they spin - they're cooked.

Good Luck.

Capt Ross

Panther 05-30-2007 08:51 AM


Originally Posted by Strip Poker 388 (Post 2144445)
After they cool off it will get back on plane but slips after about 5 miles.

Rob, just re-read your post.. I've never seen a coupler do that. In my experience they're either good or bad, this would be a first for me.

If you look behind the engine and don't see any metal shavings or rubber bits I'd start looking at the drives. Swapping them side to side may help him get thru the season if he wore out the clutches.. :(

Strip Poker 388 05-30-2007 09:06 AM


Originally Posted by Griff (Post 2144574)
I would also replace with the HD couplers used on the 575sci and up-#21 in the diagram.

http://www.mercruiserparts.com/Show_...ler+Components



Being stock motors they shouldnt need the new style 525 couplers . Does the new style require the new style drive shaft going into it?

Like articfriends says I dont think TQ is getting them.I really dont think abuse or inexperience is getting them. I need to ride with him and see ,if so teach him some.


This guy has had cruisers before just not powerboats.He knows about trim.If its trimmed up on take off it will just blow the props out,want get on plane.


I have seen when a coupler spins out , they say it gets hot and then spins the rubber inside the coupler ,being if its not real bad ,you can idle a while it will cool off and ease back on plane.Sometimes:D

I was always told if its eats the splines, meaning making them into sharp points its a lack of lubrication/grease. Is this true?

OSO Steve I hadnt thought of clutch in the drives.That could be it this time and not the couplers.

I haven't seen the parts to see if the rubber is/was slung out or even if the shop really replaced the old ones.I know one of the mechanics there, he is pretty good but I know they have never worked on a boat with offshore mounts before :eek:

Linster (Linnie) on most I have seen there is just a little play in the bolt holes on the front offshore mount. They may need to do like you said if its out too far.


He just bought this Cig and Hasn't had nothing but problems,He's getting alittle discouraged. You can tell its had a lot of saltwater use:( I can tell these are not the original motors and the bilge has been repainted/gelcoated.


Thanks for all the suggestions keepem coming.
Rob:drink:

Strip Poker 388 05-30-2007 09:10 AM


Originally Posted by Edward R. Cozzi (Post 2144727)
If he's a new boater, does he know you must trim the units down before taking off?

I've also seen the bellhousing mounts collapsed and causing the alignment issue.


Thats another thing I need to get him to tell the shop,

Hell they could of even left out the spring washers:eek:Theres no telling.

Griff 05-30-2007 12:26 PM


Originally Posted by Strip Poker 388 (Post 2144825)
Being stock motors they shouldnt need the new style 525 couplers . Does the new style require the new style drive shaft going into it?

I was always told if its eats the splines, meaning making them into sharp points its a lack of lubrication/grease. Is this true?

Rob:drink:

I used the new HD coupler bolted to my 525sc/Imco drive with no modifications.

Sharp splines=wear from use. Lack of grease will drastically accelerate the wear.

Wobble 05-30-2007 12:31 PM


Originally Posted by Strip Poker 388 (Post 2144826)
Thats another thing I need to get him to tell the shop,

Hell they could of even left out the spring washers:eek:Theres no telling.

Not likely, it would be a bittch to get the drive in if that was the case. I'd be looking at the drives themselves or the hubs in the props

cuda 05-30-2007 12:36 PM

There will be no doubt if the coupler burned up. The first time it happened to me, I could have sworn the engine was on fire. Black smoke everywhere, and the smell of burning rubber was unmistakable. Once it cools down, the rubber may hold for a while, enough to ease it on plane. Did he burn both couplers both times? I don't believe in coincedence. If the couplers burned, it was something to do with the way they were installed.

Wally 05-30-2007 02:05 PM

From a machining standpoint...how about checking the alignment when rotating the engine every 90*? maybe the coupler is crooked....internally...they could be aligning it as it sits...but as soon as the engine starts the runout will kill everything if its crooked....just a thought


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