TOPIC: broken shaft

I've got a 79 Bayliner 17ft with a mercusier 140 Power Trim (#5199784}. The vert drive shaft sheared just below the upper splines. The splined part is still in upper unit. I figure to replace the lower unit but I'm not shure about what will match up.
Also I havent been able to find out the gear ratio on mine.
I think I can perform the repair with a little help. I welcome any advise and/or tips.
Thanks in advance
HOPING TO BE BOATING SOON!!!!

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www.fergusonpoolemarine.com

1.98:1 ratio for a 4 cylinder. The gear ratio takes place in the upper unit. All lower units had the same ratio (1.65:1)

Any MerCruiser #1 drive from 1970 until 1990 (includes Alpha 1 gen 1). Earlier drives from 1967 thru 1969 will look similar but the splines are different. You need 13 splines.

Alpha 1 gen 2 will not fit.

jimandros wrote:

1.98:1 ratio for a 4 cylinder. The gear ratio takes place in the upper unit. All lower units had the same ratio (1.65:1)

Any MerCruiser #1 drive from 1970 until 1990 (includes Alpha 1 gen 1). Earlier drives from 1967 thru 1969 will look similar but the splines are different. You need 13 splines.

Alpha 1 gen 2 will not fit.

Thanks,
ANY lower unit from 1970 to 1990, (Type-1,13-spline & Alpha-1,Gen-1}, will match my existing upper?
COOL!

Now to get the broken driveshaft splined end out of its reciever in the upper units "driven gear"

I've already seperated the lower unit hoping not to have to touch the upper gears, but I fail to find a way to disloge the splines.

So...I pulled the upper unit. Have tools and manual.

I found a disturbing amount of water in the U-Joint bellows when I removed the upper unit. Is that normal?

There should be NO water in the bellows. That should be replaced otherwise, if it totally fails, boat will sink...

The shaft should just pull out BUT it's broken ay the o-ring groove, so nothing to grab onto.

I would remove the input (u-joint) shaft, top cap and then the gear/shaft from the upper unit. Broken shaft should drill pretty easy, then thread it & pull it out.

You could try drilling with an extension bit working from the bottom but a total disassembly/inspection wouldn't hurt.

This would be from my experience with farm equipment. Splines can wear and somewhat lock together because they can twist so part of the alludes are lined up and farther down the shaft after a twist the inner splined shaft does not line up with the outer part. Not sure that is worded for the best u understanding but if it is wore and broken the way I am thinking it will not be much fun to take apart.

I finaly got the broken spline dislodged and the upper unit back together.
Any tips out there concerning the u-joint bellows replacement?

Update...
I managed to get all the bellows removed. Took care of the water, gimbel bearing and u-jounts. The shift cable is in very good condition so I plan to reuse. The cable bellows was in the worse shape.
Today I start installing the new QuickSilver bellows.
I managed to locate a good used alpha-1, Gen-1 Lower unit. I should get by weeks end.
YIPPPY!!!!

I recieved the lower unit I ordered, got the bellows installed and got everything put back together. Test floated with no water leaks and she fired right up and ran great.
Thanks for the advice everyone.