TOPIC: Early 1500xs 6 hole gear case

I have an early probably 1976 1500xs gear case that is completely empty that I am trying to swap internals into. Its the 6 hole intake. (later only had 4 intake holes)

I have the XS bearing carrier but I am having issues finding the right drive shaft bearing and lower water pump base.

1500's show two different driveshaft/bearing combinations during there run. One is ball and one is tapered roller. 4121435 is the cut off serial number between the two styles.

The early is: 63326T BEARING-BALL under pump
The later is: 69220T BEARING TaperROLLERunder pump

The early is: 48747A1 Lower WPump base assay.
The late is: 96146A5 Lower WPump BASE ASSY


Now comes my problem. The early bearing and WPUMP base are too small. And the later bearing and WPUMP base is 20 thou too big to fit in there. I have both styles to try to put in there and I cannot get anything to work.

Does someone know of a 3rd option for the XS lower units? Any help would be great. Anyone have an early 1500xs parts breakdown? 1976.... I can find from 1977 and later, but I cannot find the 1976 parts breakdown .

Thanks
Conrad

I have a couple of gearcases in the garage I will check and see if any are the 6 hole. The water pumps are exposed so I can measure. Never seen a 3rd option though.

The whole pump has to come out to see the lower base section that fits into the lower unit. Just above the bearing.

Hi Conrad,
I have e-mailed you using the last address I had for you. I believe that we can help with the correct parts (as I described in the e-mail) if you wish.

Regards,
Joe
www.fergusonpoolemarine.com
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Thanks Joe. Great talking to you today. I think you mentioned it as well as another man on BRF that my case might be a 850xs instead of a 1500xs.

The other gentleman mentioned that it might not work putting straight cut 2.0 or 1.78 gears from a 1500 into a 850 case that had 2.3 helical gears.

I need to do some thinking.

Anyone ever take 2.0 gears and put them in a 850 case by chance? That would be the same thing I am thinking.

Conrad

Well I thought Id update what I could find out. This case turns out to be a 850xs and the short of it is there is not any easy way to put 1500xs internals inside of it.

The 850 units had spiral cut 2.3 gears, that means the drive shaft bearings were set up to pull down towards the prop shaft and thus had different bearing and different driveshaft.

The 1500's had straight cut 2.0 or 1.78 gears and they push up away from the prop shaft naturally.

I think Mercury forecast someone trying to do what I am trying to do and they made it very hard to swap. All the bearings have slightly different OD's and ID's then the others. Even the dive shafts are slightly different. The 850 bearing actually slides on from the pinion side with the driveshaft lip above it. The 1500 slides on from the crank side with the driveshaft lip below it. Because they are controlling opposite direction of forces.

Externally they look the same and above the lower water pump base they are the same.

The only way I can make this case work is if I have a machine shop bore out the case under the water pump .35 inch to accept the larger sized 1500 tapered bearing. I would also have to address additional shim spacers to get the bearing up higher. As the 850 bearing naturally sits lower than the 1500.

Also when raising the bearing up in the 850 case you run into blocking the oil passage to the upper bearing. It also would have to be modified to get past the new location.

Some may ask why not just use the 850 drive shaft components and swap out the 2.3 spiral gears for 2.0 or 1.78 straights. All you need to do is flip the tapered roller bearing over to control the force in the opposite direction. This is somewhat true but if yo did that particular bearing is not designed to work upside down. Nor is the drive shaft. On the 1500 tapered roller bearing there is a special extra collar on the bottom of the bearing cage that supports the driveshaft from falling down when not in use. Also the 850 driveshaft would let the bearing work its way off if the forces were in the opposite direction.

So I am left with a choice. I could bore out the case to accept 1500xs components. Or just letting it sit and someday make it into a 2.3 850 xs case when I find a donor 850 lower unit.

If someone finds anything I said incorrect please advise me. If there was a ball bearing with a .985id and 2.25od on the market I may be able to use it. But so far I cannot find one.

**NOTE: The bearing I refer to is the one right under the water pump that sets the pinion height and supports the drive shaft. Can be a roller bearing or a ball bearing depending on what year produced**

OR,...You could snag a swept-back and add a Bob's Machine nose cone kit, and get your 2:1 ratio.

Doc

Yep I could go that route. I guess Im a hard headed purist. I really want an XS case to go with my short shaft 1500. Id like to have two xs cases one 1.78 and one 2.0 when Im done. May take awhile.

Hey Doc, I wish my shed had all that amazing stuff in the background of the pics!!
Nice.

Do you mig weld or tig the cone?