Mercruiser 3.0 Shift Shaft Issue

[ken_23434]

Any idea why the lower shift shaft (gear housing) is sitting low and becoming disconnected from the upper shift shaft (bell housing)?

I took the boat out for a evening cruise and ended up running it into the boat ramp when it would not go into reverse.

When I moved the throttle to the rear to apply some reverse, it stayed in forward (I did not realize that) and when I moved it back and the engine reved up a little, it cause the boat to speed up (forward) instead of slowing as I expected.

I checked it on the trailer once I got home. I suspected a shift cable issue, but I found the shift shaft in the gear housing not meshing up with the corresponding part from the bell housing. (the foot looking piece was not in the "socket" from the bellhousing.)

The shift shaft from the gear housing was sitting lower than the shaft from the bellhousing. I was able to align them and raise the lower one to match the upper one. Then it would shift back and forth (sitting on trailer) but eventually the lower shift shaft would drop down and become disconnected from the upper one. And then the drive would stay in what ever gear position it had been.

I just spent about an hour reading through service manual #6, and I did not see anything in there about shimming either one of those shafts or anything that looked like some maintenance item I need to go do.

This is NOT a shift cable issue, something in the lower unit.

Yesterday, I took the boat out for the first time for the season and it worked OK.

Over the winter, I did pull the gear housing off to replace the water pump as routine maintenance.

89 Mercruiser Alpha 1.

Ken

 

[Don S]

Re: Mercruiser 3.0 Shift Shaft Issue

Any idea why the lower shift shaft (gear housing) is sitting low and becoming disconnected from the upper shift shaft (bell housing)?

Yes, the SS washer going over the shift shaft is missing.

 

[ken_23434]

Re: Mercruiser 3.0 Shift Shaft Issue

Thanks Don,

Is the proper way to correct merely to put the SS washer in there, or should I replace the rubber washer and shift shaft bushing also?

 

[Don S]

Re: Mercruiser 3.0 Shift Shaft Issue

Disregard, I misread your post completely...... Actually, didn't read it completely :redface:

Will get off line now, and read again tomorrow.

 

[ken_23434]

Re: Mercruiser 3.0 Shift Shaft Issue

Don,

I think your initial reply might be right on the mark.

I had some debris from an old exhaust flapper in various parts of my lower unit. I did take my shop vac to "clean up" some of that junk from the gear housing.

Since I did not know there was a washer on top of the shift shaft (aren't washers always squashed in place with a nut?) I could have inadvertently sucked it out with the shop vac. :redface:

I will know next time. Luckily, online the price is listed for under a dollar. I was already approaching the dock very slow, so the impact with the ramp was minimal. There's a small scrape on the bottom, not bad.

Heck, it was late and no one was at the dock fishing or anything either. So, I didn't even lose any "cool points" (did I just reveal my age).

 

[ken_23434]

Re: Mercruiser 3.0 Shift Shaft Issue

I picked up the SS washer and the rubber washer today at Bill's Marine. $2.10 for both after tax. I will tear into the gear housing later to see if those parts are missing.

For anyone in the Hampton Road's Area, Bill's Marine has great parts service. I should know the guys name at the counter by now, but he is very helpful with all my dumb questions. It's not really near any water, so I think a lot of people do not think of heading over to Portsmouth for their parts. I cannot speak to the boat sales, never bought a new one. Only about a mile from 264.

 

[bigskiohio]

Re: Mercruiser 3.0 Shift Shaft Issue

what rubber washer?

 

[Fishermark]

Re: Mercruiser 3.0 Shift Shaft Issue

It's a common enough problem that I saved the pic on my computer :

 

[ken_23434]

Re: Mercruiser 3.0 Shift Shaft Issue

The SS washer was the problem.

Took me about an hour total to pull the gear case put in the washer and put it all back together again.

It almost looks like the washer is there by mistake. But, it turns out to be a BIG mistake to NOT have it there as I found out.