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serial numbers?

Trying to find out about my outdrive. where can I put the serial numbers in to find out what I have? Was on a site that only does 1991 and newer. Mine is 1985.
 
The 290 (in the PZNR #) would represent a 290 transmission.

The suspension fork and set pin suggests that it is a 280 style transom shield.

If the last character is a "D", it would represent a 2.15:1 reduction, of which is for the 4 cylinder engine.

However, these drives offer a large array of interchangeability, so you may need to pull the prop shaft ring anode and look for the numbers that will be stamped into the bearing carrier.

The final reduction occurs within the lower gear unit.

Your options are:

2.15:1 = 4 cylinder engine
1.89:1 = inline 6 cylinder engine (not used in 1985) and some 4.3L V-6 engines
1.61:1 = V-8 engine in either the GM small or big block, and/or the Ford.

With any of these s/p drives, the gear oil must be 30W.

What is it that you are wanting to do?


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Really just want some info on it. I was told it was a 280, it is behind a SBC 350. Where would I find numbers here?

View attachment 25846

You'll need to take a wire brush to area.
The reduction number will be stamped into the prop shaft bearing carrier.

It won't be a complete number.
If it's a 1.61:1 (V-8 ratio), you will see 1.61 only.
In other words, it will be minus the :1.

However, that's only good if no one has changed the gear set and failed to re-mark the carrier.

The good news is..... it's doubtful that anyone changed the gear set!
It's not cost effective when you can find a good used lower unit with the correct reduction.


The reason for the 30W gear oil is due to the die cast slinger pump.
If heavy gear oil is used, we risk shearing the slinger pump impeller drive pins.

There is a simple test that you can do if you suspect that heavy oil was used.


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Should I use straight 30 weight?

If in cold water, yes!

If in warm Florida waters, then use 40W.

Although you did ask, when changing the drive shaft bellows, remove the transmission ONLY.
If removing the entire drive, remove the transmission first, then the remainder of the drive.
When going back together, install the transmission last.


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Yeah, I already changed the bellows, only removed the transmission. In Rhode Island, so yes pretty chilly water. Water temps don't get much higher than 68 or so in the thick of summer.
 
One other thing, and again not asked for....... PDS bearings!
Have you replaced them?
These are often over-looked.
Owners forget to service them.

An AFT PDS bearing failure can be very expensive.


Another non-asked for thing.......... the transmission's brass split ring keeper!
Have you examined it for expansion?


Don't misunderstand me..... these are basically bullet proof drives.
However, there are a few things that require periodic replacement.

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I will be doing the bearings when I pull the engine in the spring. Already have them and the seals. Will probably change out the u-joints also. I have no idea what the transmission's brass split ring keeper is. Is that the sleeve between the drive and transmission? How can I tell if it's expanded?
 
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I will be doing the bearings when I pull the engine in the spring. Already have them and the seals.
Good call.
You will never know what headaches and expense you will have prevented.

Keep in mind that you'll want to Pre-Fill the grease cavity (while spinning the PDS), prior to installing the AFT seal.
Make sure to glue and stake the FWD seal into position. You DO NOT want this seal to be pushed out by excessive grease force.

Will probably change out the u-joints also.
Use caution when removing the 4 clamping collar cap screws.
Heat is your friend!

I have no idea what the transmission's brass split ring keeper is. Is that the sleeve between the drive and transmission?
You might be thinking of the vertical shaft spline coupler.

s-l300.jpg


Those typically don't go bad.
They are designed to shear in the event of an impact.
However, they can become twisted.


The split ring keeper is this part with my green arrow pointing to it.
This part encompasses both halves of a split ring (not visible in the image).

attachment.php


How can I tell if it's expanded?
The OEM are brass.
Over time, and when driving from the lower driven gear (i.e., LH prop), the shaft's up-lifts force will cause them to expand.
When these begin to expand, the sides are no longer parallel to one another.
You can easily check this between the jaws of your dial-indicator calipers.


I have these in stress-proof steel (custom CNC made) if interested.





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If you take the transmission completely apart, you may as well lap your sliding sleeve to the gear cups.
Watch for and inventory all shims. They must go back where they were.





fetch



Clean all lapping compound from the surfaces, add a bit of oil to the surfaces..... and you'll be good to go!



Edit:

Here's another trick that works well.

Run an 1/8" Tapered Pipe Thread tap into 12:00 O'clock position Flywheel Cover port.
Clean the debris.
Install an 18" grease gun extension hose into the threads.
Install a zerk fitting into the end of the hose.
Zip tie the zerk fitting end to the throttle cable bracket where will be easily accessible.

attachment.php





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I'd be suspicious as to why there is a "fin" on the drive.... Usually indicative of an under powered boat ( or incorrect drive reduction).
You didn't provide any info on the hull its on.
 
dang it's me.... did you read posts 13, 14 and 15?



By the way...... a properly built 5.7L SBC will work best (in this hull) with addition of the 1.95:1 Duo Prop lower gear unit.
The Duo Prop will offer 25% to 35% more thrust to the water.


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I did read the posts Rick, very informative... Thanks.

Which model lowers would fit my drive? Is it an easy swap, say like swapping the lower on a Mercruiser?
 
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With the AQ series (minus the correct reduction), all lower units are interchangeable.
If were to install a Duo Prop lower unit, you will need an AQ series in the 1.95:1.

There will be some very critical shimming involved. It is very doable with the right instructions, and no out of the ordinary tools are required.

If you go that route, start a new thread and I will walk you through the procedure!




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