Engine Coupler Question

[GaJeff]

81 mercruiser 120hp with MC 1 outdrive. Posted a threa the other day about my prop may have spun a hub. Well my bellows are leaking and my gimbal is growling anyways so I am doing a gimbal bearing and bellow replacement before I do the match-mark test on the prop. I was advised that I could have a spun hub or engine coupler could have broken so while everything was torn down I wanted to check this. I know it can't be changed without removing the engine and also if I put it all back together and it is bad I will have to remove the outdrive again so I want to be absolutely sure before I proceed. Everything is 100% stock which is seemingly surprising for an 81. So it probably needs to be replaced anyways.

Back to the tech..... I have my shaft out and u-joints out for replacement. I took my engine side of the shaft and put it in the coupler and tried to turn the engine. It turned but the engine did not. Is the coupler some sort clutch pack or is it a solid rubber type of bushing? When it's turned should the engine crank be turning with it or not? It's bolted to the flywheel like a clutch but then again Im not sure.

Any help or advice would be appreciated
Jeff

 

[Bt Doctur]

Re: Engine Coupler Question

were there slivers of aluminum ? shaft turns ,engine doesnt means the coupler is shot.

 

[stonyloam]

Re: Engine Coupler Question

I know it can't be changed without removing the engine

You probably would not have to "remove" the engine (not like a car) You would have to unbolt and lift it up enough to move it forward (or push the boat back) enough to get a torque wrench on the coupler bolts.

 

[Grub54891]

Re: Engine Coupler Question

If the shaft turned and the motor did not, you need a coupler. So much easier to pull the motor and do it. If ya never done it it's not that hard in my book. You could get some different colored electrical tape from the dollar store and mark the harness wiring so it goes back together the same way you took em off, they are all plug and play mostly anyway. And 4 motor mount bolts,out she comes! But you will have to check the alignment upon installation.
Grub

 

[GaJeff]

Re: Engine Coupler Question

Yea I figured it was shot... I saw a coupler at the store and it pretty much looks like a direct drive type of bushing. No clutches or anything. It bolts to the back of the engine and the shaft goes in... Simple as that. So if it turns and the engine doesn't, it's pretty obvious.

Well good news... I'm a diesel mechanic and I own a pretty big shop with a 10ton overhead crane so pulling the engine shouldn't be nowhere near as difficult as a Detroit in a cleverly designed Volvo. I should be good. I've already rewired most of the engine harness and had to rebuild my trim pump motor with stuff around the shop.

My initial problem was the spun hub theory, that could also have been a coupler so thanks for the input. Looking a few alignment bars now so hopefully I can get this fixed before the summer is over.

Jeff