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Greenhorn Trying to Fix Lower Unit Help

S

searcyfarms

Member
"Hello, Thanks in advance to a

"Hello, Thanks in advance to all of you for whatever comments or advice you may offer. I am attempting to fix my broken boat. My father in law bought the boat new in 1984. It has a 488 mercruiser on it.

I have diagnosed the problem to be in the lower unit and have removed it and found a replacement. The fella that sold me the lower unit said it is not a TRUE Alpha drive even though it has the Alpha case since it was produced in 1984 and it also has a preload pin on the tip of the gear that inserts into the upper part of the outdrive.

So my question, how do I get this thing apart to replace the parts inside? The gears on the tip of the upper shaft are twisted and the gears/bearings in mine seem to be out in some manner. It is clickin and making noise like a rough bearning, not to mention the grey/silver looking oil from all the ground up metal inside. The man that sold me the lower unit assembly said I will need some kind of special tools. Is that accurate? No one around here will work on my unit since it is over 20 years old they tell me.

I have no idea how to work on one but I did get it removed and grew up on the farm working on everything under the sun so I guess it cannot be too much different than a combine, tractor or anything else. Bearings, gears, shims, spacers, shafts, bushings etc....

THanks again,

Robert"
 
robert was the gear oil all gr

robert was the gear oil all grey or just in spots-swirls sounds like that unit took some water
 
"The 'special tools' i

"The 'special tools' include the spanner wrench for the carrier nut and the shimming tools to set the gears up correctly, just like the ring and pinion in an axle. The rest are more "normal."

Get yourself a manual and read it before you take on an overhaul. To do it right will take some time and it isn't just a regular R&R job."
 
"well, i changed the lower uni

"well, i changed the lower unit oil last week and noticed a couple little pieces of metal about the size of a pin head and then some fine shavings on my finger when I drained it, that was my first indiciation something might be wrong

so when I went to the lake thursday and drove it about 5 minutes it was making a ticking sound like maybe a took burr or chipped. Tick tick tick, so I thought i would drive it a little more and hooked up the tubes and we went about 10 minutes and it kept getting louder and louder and it almost seemed like it was growling and grinding/very intense tap tap tap or clack clack clack.

Then it felt like it possibly jumped a tooth or bound up. The boat kind of shook and it was a loud clang and we were of course about 1.5 miles from the boat ramp so I idled it back in gear around 700rpms.

I removed the drain plug when at a boat repair shop friday and it was very grey/aluminum in color with lots of shiny metal pieces.

It did not get water in it. I think maybe 25 years finally did it in."
 
"I know what shims are on a 9&

"I know what shims are on a 9" ford rear end but never needed a tool for those, they are basically like a very thin washer on those.

Is a spanner wrench something that is available or something that could be made to work?

The replacement lower unit gears seem to be in good shape, tight and no noise. The only reason I do not want to use the entire assembly is because it is beat up and the skeg is broken. My housing is in near new condition."
 
anyone around the Kansas City

anyone around the Kansas City area that might be interested in looking at this with/for me and has the proper tools?
 
Robert I would suggest getting

Robert I would suggest getting a Clymer Mercruiser Shop Manual. I have one for my 81 mercruiser. It covers 1964-1985 mercruisers its about 2 inches thick. And it has very detailed step by step instuctions for rebuilding lower units. It has everything in it from rebuilding the lower unit to rebuilding the engine. You will want to have one of these. I got mine on Ebay for $30 bucks. Hope this helps
 
yea the outdrive is most likel

yea the outdrive is most likely shucked I found a donor drive for a great price and it seems good so am trying to find someone that will transfer the parts since I do not have a spanner wrench nor a shim tool that is required for these. The fella told me if any of the parts in the donor are not usable he would fix me up. I am for sure going to have a seal kit installed
 
"If you have metal in the driv

"If you have metal in the drive and you want to use some of the parts, the entire drive should be completely torn down as you will only contaminate the rebuilt drive.

Can't mix the lower from a pre-alpha with an alpha.

To separate the drive, loosen the screw above the trim tab zinc above the prop, remove the 2 nuts above the prop then the 1 nut at the very front then the 2 nuts on either side, the lower unit should separate."
 
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