B3X upper gearset lash

Setting lash on upper gearset on a b3x S/N 2A335953. Drive was used w/83 hours, changing from 2.00 to 2.20 (23/30)-new gearset and bearings, but reused thrust bearings/race. I set pinion depth with the tool and it's to spec- went to adjust lash and got 0.019 on both to and bottom. Top race measures 0.061, bottom race measures 0.063. Book says 0.011-0.016 is spec. Soo is that because the thrust bearings have been worn in? If so, do i set it a little looser? Also, the bottom being a .063, I am adding .005 and that shim is not offered, they stop at 0.067, can I just use a thinner shim on the pinion?

What are the stamped numbers in your upper housing?

Which pages are you looking at to obtain specs in Manual 28?

Assuming you have all the tools and are following the service manual.
That you have the exact same out of spec backlash on both gears is a bit of a red flag, guessing that it’s because of new gears and not wear. But when something unusual like this happens I would double and triple check my work. Using the correct flag and have the dial indicator at a perfect 90* to the flag?
I would recheck the pinion depth, suggest you use the.025 on one tooth and then try a .024 and .026 on the other tooth.
The available.067 race will get you in spec and loose is always better than tight.
This is a situation that I would probably check the contract pattern on the gear teeth like Volvo does with their gears. Moving the pinion in a little would be the easiest thing to do, But I would sure check pattern first.

alldodge said:

What are the stamped numbers in your upper housing?

Which pages are you looking at to obtain specs in Manual 28?

Click to expand...

Merc quit stamping numbers in the upper awhile back.

Hope O.P. isn't in #28, that manual was like 600 pages in it's last version.
Should be in #39, it's 6 books with about 1200 pages.

Got to give a weekend warrior kudos to attempt this job, MerCruiser has made working on the new Bravo's soo tool intense.

#28 doesn't even mention backlash in the upper. At school they tell you to you to use your finger and make sure there is some.

Now in #39 with the newer drives. Just to set pinion height and check backlash in the driveshaft housing you will need 10 special tools (that aren't used anywhere else) that will cost $700. But if you want to do just one gear ratio and only do standard or X drives (pick one) you can shave that down to 6 tools and $500.

But, I guess if if you want them to last longer with todays higher horsepower. I costs money.

Tooth contact pattern is very important.----More so that actual backlash.

muc said:

Hope O.P. isn't in #28, that manual was like 600 pages in it's last version.
Should be in #39, it's 6 books with about 1200 pages.

Click to expand...

I wouldn't be surprised if Merc had even a newer version by now and looking up the serial number in question seems to first suggest it's pointing to use number 28 but starting in January of 2022, they have a supplement part number 8M0185811 which ought to help with any updates even over 28 and possibly most of the 39's I'd only presume without up to date training, https://www.mercruiserparts.com/bam/subassemblydetail/51192064/28199641


Which then led me to a different area of discussion regarding the high bump vs low bump gear and shifting side of it all... So, while I'm not sure if the high / low would affect this conversation, it's at the very least should be known of to ensure the correct parts have been ordered and received or should further parts investigation be needed by @Rob the weekend warrior,