1990 4.3L mercrusier alpha outdrive not spininng prop

[wakerush]

I have a 1990 wellcraft 186 eclipse with a 4.3l LX with a alpha outdrive that is not spinning the prop. I was using the boat the other day and i was running fine until I was idiling aroun the dock and it just stopped goin forward. No noise or grinding. If I put in gear the engine just revs and the prop doesn't move.

 

[boat127]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

i would pull the prop and put a white line ont he prop then on the hub take it for a spin and remove the prop and see if the line moved if it did you need a new hub

other things could be coupler but that often causes temperature to rise
bad shift cable causin it not to go into gear
or bad chewed up teeth in the upper unit

 

[wakerush]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

I put a another prop and the same thing is happening. I removed the top cover of the upper unit and from what i seen everything looks good. I started the boat and put it in gear and nothing was moving in the upper unit either. I dropped the lower unit to see if the shaft moves when I spin the prop and it does, forward and in reverse. The shifter cables are working correctly if I put it in forward wnd can move the prop one way and if I put in reverse i can move the opposite way, right?

 

[PS94]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

Time to pull the leg off, and check and see whats up with your u joints, and splines. Does it get water? I just fixed a guy's boat, he disbaled the low oil alarm, and ruined the pinon gears, resulting in no motion, and the lower water pump wasn't functioning.

 

[incrediblened]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

The first thing I would check would be the engine coupler. Start the engine. Look at the back of the engine. See if the coupler is spinning, but not your outdrive yoke (that shaft that sticks into the back of the engine through the transom.)

 

[wakerush]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

Alright here is what is happening. I dropped the lower unit to see if spining the prop spins the shaft and it does. I put lower unit back on and refilled oil. I opened up the top of the upper unit and sarted the boat..put in gear...nothing moving in upper unit. No grinding..no nothing. I took yalls advice and started the boat put it in gear and looked at the shaft at the rear of the motor going out to the upper unit and it is not spinning. At the rear of the rear of the engine where the shaft comes out what looks like a doughnut is spinning. Any ideas on what is going on. If the prop is not spinning it is not getting water, correct?

 

[Bt Doctur]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

Sounds like a bad coupler

 

[stonyloam]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

Sure sounds like the Dr. is right! Here is what it looks like in the parts breakdown:
#9 http://www.mercruiserparts.com/Show...nbr=951&bnbr=190&bdesc=CRANKSHAFT+AND+PISTONS It bolts to the flywheel and couples the motor to the driveshaft of the outdrive. Click on the part number for a photo.

 

[wakerush]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

I appreciate the info. How bad is the replacement?? What would you guys recommend, do it yourself or take it somewhere. Does the motor and outdrive have to be removed.......

 

[Bt Doctur]

Re: 1990 4.3L mercrusier alpha outdrive not spininng prop

Remove the drive first
Remove /lift up the motor ,remove flywheel cover , replace rear motor mount bushings,,R/R coupler, reinstall, realign, install drive.