280 Outdrive gear box or new outdrive ?

[big_b]

I have been working with some other guys have my AQ130D motor running great now (except for the sticky throttle)

My upper gear box on my 280 outdrive is totally stripped.. I have found a few options but not sure where to go next.

Ordered a upper gear box for a 275 outdrive, hoping it would be able to be shimmed and fit on my 280 (found it for $100)

A local Marina has several 270 outdrives, I am not sure about gear ratio as I cannot find them on my current outdrive usnignthe manuals instructions. Will the 270 bolt right up in place of the 280 ?

I found a few outdrives on eBay that are 270/280


Seems like the shimming is a very big deal and I do not want to mess it up as far as shimming it wrong.

If I buy a 270 or 280 is there anything hard I should know about bolting it up in place of my current outdrive ?

Thanks,

 

[Don S]

Re: 280 Outdrive gear box or new outdrive ?

Shimming the upper gear box to the intermediat housing is easy to do if you can read a depth micrometer and add and subtract.
The problem with replacing just the upper gear box is your old one being stripped.
I assume this means the gears are destroyed. If so, all that metal is in the lower unit and it will probably need replaced too.

What you have to look at with used drives, is not only their condition, but the gear ratio, and the type attaching bolt for the helmut.

 

[captmello]

Re: 280 Outdrive gear box or new outdrive ?

The gear ratio you need is 2.15:1. That is the standard ratio for the four cylinder engines of that era. The ratio may be stamped on the tag on top of the upper gear box, or you can put the drive into gear, and turn the ujoint around once and see how far the prop/prop shaft rotates. should go just under half a turn for each rotation of the motor(ujoint)

 

[PiratePast40]

Re: 280 Outdrive gear box or new outdrive ?

Gear ratio is also stamped on the lower bearing housing. Pull the lower zinc to get a look at it.

I believe the ratio is also stamped on the tag for the gearbox but uppers and lowers may not be original.
B-1.61:1 (V8)
C-1.89:1 6 cylinder
D-2.15:1 4 cylinder

With any outdrive, might want to make final payment contingent on the amount of water the comes out the drain plug and if it passes pressure and vacuum tests.

HELMET BOLT STYLE - but I guess you've figured that one out by now

BTW -I did a search on "helmet bolts" and found some good info. Suggest you do it yourself so you can find out first hand.

One more thing to think about: Since the bellows was shot, there's a chance that there may have been water in the primary drive shaft bearings. Those are located in the flywheel cover (bellhousing). Bit of a pain but now is the time to change those.

If you scroll down below this thread, you'll see a list of related links. Those can often times lead to some really good additional info. Just keep in mind that the results are related to the wording of your post title.