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Lapping Cone Clutch

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mike77cj

Regular Contributor
"My outdrive slips and looses

"My outdrive slips and looses power above 3400 RPM. I have disassembled the upper gearcase to remove the brass cone clutch to lap it. Upon inspection of the cone cluth it does not appear to be badly glazed. The factory machined grooves in the cone cluth are still apparent, but not very deep. I did notice a considerable amount of glazing where the cone clutch seats on the upper and lower gears. I used some fine grit sandpaper to remove this.

How should I lap the cone clutch? Can I get away with just sanding the face with some 220 grit?

Also, when I removed the cone clutch it was in upside down, with the stamped TOP marking facing the lower gear, not the upper gear. Would this cause the slipping?"
 
"What oil are you using? If yo

"What oil are you using? If you want to prevent clutch slippage, make sure you use engine oil, not gear oil.

To deglaze, I would use fine valve lapping paste, then wash all the parts thoroughly with Varsol or similar.

The part that says "top" must be at the top. Maybe someone before you had your same problem and figured out that reversing the sleeve it would be fixed?"
 
"I ran straight 30, then 10-40

"I ran straight 30, then 10-40 and with both oils slippage occured.

I just finished lapping the cone and seats and they look good.

I will fill with 30W and give it a whirl.

I know that VP does not advise using gear oil, but I have never fully understood why. Is it because the higher viscosity oil would not move through the roller bearings adequately?"
 
"The first time it also surpri

"The first time it also surprised me, as I was used to put gear oil into Mercruiser outdrives. However, when the manufacturer gives a spec, I believe that the safest thing to do under normal circumstances is to follow it to the letter. If you don't, you may end finding the hard way why that spec was made. Morten Ringvold has stated that the original reason was convenience, i.e. one type of oil fits all. However, I have read in the forum of members using gear oil and getting clutch slippage and shifting problems. Whatever the case, I see AQ outdrives that have been running for 30-40 years on engine oil and are still in excellent shape; most of them still have the original gears, and some even have the original bearings. Therefore, I apply the old "if it ain't broke, don't fix it" and stick to engine oil (which by the way is cheaper than gear oil)."
 
"What oil to use may depend on

"What oil to use may depend on a lot. If what You have works, stay with it.
Running a 4 cyl Volvo on a 280/290 drive, it will run until eternity with whatever oil You use.
I was mainly working with 280/290 drives hooked onto 305/350 and quite some of the AQAD Diesels. 50 hours with some hard driving and load, using engine oil what comes out is not much oil-like, and the smell tells its story.
On the taxi boats on the Norwegian west coat they made about 1500 hrs lifetime running engine oil. Changing to Volvo Synthetic, similar to Ultra HPF, lifetime on the drives went up to 2500 hrs."
 
"Morten,

My 280 drive is ma

"Morten,

My 280 drive is matched up to a 320 hp 350. It pushes a 23' Formula. I run the boat at 3,000 rpm, never tow skiers and overall am gentle on the throttle.

In another post you mentioned it is OK to use 80W gearcase oil. I was thinking of using Lucas 80-90W. I have had good luck with their products in other applications. Will the heavier weight oil adversely affect the bearings?

http://www.lucasoil.com/products/display_products.sd?iid=43&catid=4&loc=show

I also thought that the higher viscosity oils better absorbed moisture, which may be helpful in an outdrive. Any comment on this?"
 
"I have a 350 Chev (ex AQ3

"I have a 350 Chev (ex AQ311, 307 HP) attached to a 280 outdrive. I use engine oil (15W-40) in the outdrive and so far have no problems. However, if one day I notice that the oil starts deteriorating prematurely, then I will consider trying gear oil as per Morten's advice."
 
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