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BigFoot repair after malfunction of reverse gear.

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BanTir

New member
Hello All
I'm Lukas, and this is my first post on this forum. I hope, I will find help here.


I have Mercury ELPT 90HP, 2-storke with BigFoot lower unit. Serial no. 09962873.
Engine is in good condition, but When I bought, engine didn't have reverse gear. I'm trying to repair this, now. I have all new bearing, seals, I reparied reverse gearwheel and clutch.
But, during assembly, I see a problem with axial clearance of the propeller shaft. You can see this on this movie:
https://drive.google.com/file/d/11QFIyKFGTu3WuhDzgmSedfW1EN1Ei2zh/view?usp=drivesdk


When I disassembly lower unit first time, I saw, the thrust bearing has dropped between the housing and the toothed wheel. That's happed because, reverse gearwheel had also too big axial clearances.
This is normally in this lower unit? What I can do to eliminate this slack?


Other problem is, when reverse gear is engaged. Clutch touch teeth on the reverse gearwheel only on the 60%... You can see more on the photos. Something is wrong adjusted? How to do this to have bigger surface of the touched teeth?


Here is a folder with photos on the OneDrive from disassembly, inspection of the parts and grinding gearwheel with clutch:
https://1drv.ms/f/s!AkJqECnhCE-8njs8ca-tq8uPR0m1


Also on the photos is showed, how work reverse gearwheel with clutch inside lower unit (marked by yellow paint).
 
The movie didn't play for me. But I did look at some of the pics. How was the forward gear in relation to the old clutch dog? I seen all the trust bearings are destroyed. Did you replace the bearing in the carrier? Or the bearing behind the forward gear?
How does the propshaft look where the old bearings rode? Is it scored?. Blue color?
Is the propshaft bent. ?
Was there any filings or chunks of metal In the gear oil. Or in the housing?
 
mechanicman said:
The movie didn't play for me. But I did look at some of the pics. How was the forward gear in relation to the old clutch dog? I seen all the trust bearings are destroyed. Did you replace the bearing in the carrier? Or the bearing behind the forward gear?
How does the propshaft look where the old bearings rode? Is it scored?. Blue color?
Is the propshaft bent. ?
Was there any filings or chunks of metal In the gear oil. Or in the housing?
Click to expand...

Hi

I transferred movie to the youtube: https://www.youtube.com/watch?v=4SpmpUWlu4M
I changed all bearings in lower unit, also in the carrier. The forward gear working correctly, normal wear.
Propshaft looks good, I don't see any traces after blocking the bearing. I still have all on the table, so I can do the pics. I did do assembly on the new parts only for test.
I found many filings in oil, mostly aluminium from casing, because thrust bearing did do some damages.

1.jpg2.jpg3.jpg

I don't have also idea how to correctly adjust height of the pinion gear, without special tool from Mercury. For first test I used shims 0,85mm and 0,5mm for bearing of the forward gearwheel. Is it any homemade way for that?

I added more pohots from my working with lower unit: https://1drv.ms/f/s!AkJqECnhCE-8njs8ca-tq8uPR0m1
 
Mercury sells a shim kit . But the shims go above on the upper bearing of the driveshaft. That's how you shim the pinion
.i don't recommend adding shims on the propshaft. Youre asking for trouble.
 
I have this shims set, but mostly interesiting is for me this axial clearances of the propshaft, this is normal?

and How to prevent to not have the same problem with the thrust bearing in the future?..
 
Of course I did do that in first step. I checked all according to Mercury catalog, I also compared parts numbers which I have physically, with parts numbers from catalog. All looking correct. I have thrust washer, it is on photo from earlier post.

Bez tytułu21212444.jpgBez tytułu21212.jpg
 
Last edited:
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