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MerCruiser Lower Unit Gearcase Gear Set 43-878087A4 Alpha One MR 1983-1990

Item Details

MerCruiser Sterndrive Alpha One Lower Unit Complete Gearset 43-878087A4 (Pinion, Forward, Reverse)

Used in MerCruiser MR & Gen I lower units 1983-1990
- These are the correct gears if your lower gearcase DOES NOT HAVE A PRELOAD PIN on top of the driveshaft
  - ****If your gearcase HAS A PRELOAD PIN, then these are not the correct gears*****
Pinion Gear (17 Teeth): 43-42932 (Same as 43-89060)
Forward Gear (28 Teeth): 43-42933-2 ( Sometimes Stamped 17064-6022)
Reverse Gear (28 Teeth): 43-42934 / 43-824109A1
Don't worry too much about the numbers here as the numbers changed, but the gears didn't 1983-1990

Used but in great shape!
- I highly recommend that the bearings that are included (still attached to the gears) should be replaced. However it is up to your discretion as to whether or not bearings should be replaced.
Application
- For MR & Alpha One Gen I Units which have the pre-load pin in the top of the drive shaft. (If your unsure what this means, just ask)
  - This gear set will not work in a MC-1/Pre-alpha & R gearcase (I apologize for the redundancy of this statement)
- They used the same lower gearcase with all of the engines 1983-1990 so you're particular engine is not a factor here so this basically covers most (120hp 140hp 4cyl 165hp 6cyl 170hp 305 350 470 260hp 2.5L 3.0L 4.1L 3.7L 3.8L 4.3L V6 205hp 185hp 5.0L 5.7L V8 etc...
Freshwater Used Parts
Purchase with confidence!

Relevant Part Number List

43-878087A4
18-2206-1 Sierra
18-2407

Please inspect pictures closely to to ensure product satisfaction.

1983 1984 1985 1986 1987 1988 1989 1990

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Please check with your country's customs office to determine what these additional costs will be prior to bidding or buying.

This additional cost is different for every country and usually calculated with the item cost PLUS the shipping cost. The duty fees or taxes assessed are usually a percentage of that total amount (cost + shipping). It's impossible for us to pre-pay these expenses so please keep that in mind before making a purchase.

Compatibility Statement / Disclaimer

Please check with us or your parts manual if you are unsure if this is correct for you. The part numbers given here are all correct, but it is ultimately up to you to do a little bit of research and make sure this is what you need.
The compatibility statements or suggestions in this listing is my best guess based on the quick research we did for this item.

Return Policy (The Fine Print):

We try to describe all of our items honestly and accurately to the best of our ability. If you are dissatisfied with your recent purchase, please contact us as soon as possible. Returns must be made within 30 days, buyer is responsible for return shipping in most cases. We stand behind the products we sell and if something doesn't seem right with your purchase or you are having unexpected difficulties, please contact us as soon as possible and give us the opportunity to correct the issue. In the event that an item has unexpected functional issues within the return period, We will either let you keep the item and offer a full refund or ask that you ship the item back to us and offer a full refund and cover the return shipping as well.

These are used parts. Used parts may have cosmetic issues (scratches, missing paint, faded plastic, pitting, rust, minor dents & dings, etc.) The condition of this item is as described in the description and visible in the picture. You will receive the items you see in the picture (unless noted otherwise) It is being sold "as is" with no warranty.

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