Mercruiser Upper drive box (rebuild)

howe719

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Apr 6, 2008
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45
Alright so had the boat out this weekend and she was running awesome. Well we all know something is about to happen soon if all is going well with our boats.
Anyway, after a few hours on the water i noticed a loud wining noise coming from the outdrive. It was coming from the upper cap of the drive. It could only be one thing which i could think of, a drive shaft bearing.
Sure enough the motor rpm shot up and the boat stopped. just sat there.

got the boat home and started the tear down. what i came to find was that the two gears on the upper drive where shot to sh**. the bearing on the vertical drive leading down to the lower unit was shot to hell letting play happen between the two gear heads. I bought the whole rebuild kit for the upper half which run my around 400 on ebay.

my question is i cant for the life of me get the race ring out of the upper drive. i attached a picture to show which one i am talking about. I need this out so i can rebuild upper drive.

ideas please. maybe take to boat shop?? could they pull it645_2.jpg
 

Don S

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62,321
Re: Mercruiser Upper drive box (rebuild)

Her's the problem. Without all the special tools, you can't set gear hight or the other settings to get the gears set properly. You also need ALL the bearings. Did you check the lower unit for any metal particles? The upper and lower share oil.

You could have bought an SEI complete upper for about $650 with a 3 year warranty. Perhaps you can return your repair kit ??????
 

howe719

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Re: Mercruiser Upper drive box (rebuild)

I wont be able to return the parts i bought. You think i could take parts to someone that could rebuild for me? When you say 650 where to see that price at?
 

Bt Doctur

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Re: Mercruiser Upper drive box (rebuild)

Was there any oil in the upper unit? When you say the gears were shot, you mean like "smooth"?
 

howe719

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Re: Mercruiser Upper drive box (rebuild)

chucks out of the teeth. yes there was oil in the unit. I check it each year. I pump up from the bottom port until comes out top port.

I do recall when i got the boat 4 years ago when i first did the oil change it had alittle oil in it. my guest is bearing was probably about done at that point and basically held on until now.
 

Bt Doctur

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Re: Mercruiser Upper drive box (rebuild)

SE106 is the Alpha replacement. gear ratio 1.47
 

ktbarrentine

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Re: Mercruiser Upper drive box (rebuild)

I don't recall reading anything about how your oil looked when you drained it. Metal? Sure hope the lower isn't a sleeping problem child.
 

howe719

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Re: Mercruiser Upper drive box (rebuild)

the oil did have metal in it but it was almost like a dust in the oil. pretty much just made the oil thicker. i drained and flushed lower unit. seems to be working fine when spinning by hand.
 

1960 Starflite

Petty Officer 1st Class
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Jun 23, 2011
Messages
352
Re: Mercruiser Upper drive box (rebuild)

An old trick to remove bearing race is to run a bead of weld around the race surface. It will shrink the O.D. Make sure you have a very good ground.

I do agree that you will need special setup gauges to set backlash and gear height. Also, the input bearing set is sold as complete unit with bearing preload set by the ground spacer. Last on I saw was over $200. I've seen the setup gauges on Ebay, but they will also run over $200 for the two pieces.

Another old saying "If your going to play, you gotta pay".
 

howe719

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Re: Mercruiser Upper drive box (rebuild)

SE106 is the Alpha replacement. gear ratio 1.47

is 1.47 the right gear ratio??? i thought the one i had right now was 1.5.1 just wondering before i got one.

Great news the guy from ebay is going to refund my 400 for the parts. :)
 

howe719

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Don S

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Re: Mercruiser Upper drive box (rebuild)

the oil did have metal in it but it was almost like a dust in the oil. pretty much just made the oil thicker. i drained and flushed lower unit. seems to be working fine when spinning by hand.

You need a new lower too. The bearings and gears are shot with oil like that.
 

howe719

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Re: Mercruiser Upper drive box (rebuild)

You need a new lower too. The bearings and gears are shot with oil like that.

don, there are two lower units which one would i need??

could you also answer the two questions i quoted above as well about the ratio and if the units for sterndrive come ready to bolt on with gears installed?
 

howe719

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Re: Mercruiser Upper drive box (rebuild)


thanks for all your help. I will be making this purchase.

does anyone know if anyone will pay me for my cores?? my upper and lower. i would hate just to trash them.

thanks
 
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