Upper Gear Case bolted to Leg

[cpbrocke]

1987 50HP Model C. There are four 3/8 x 1 1/4 bolts the attach the upper gear case to the engine leg. One of these four had some water squirting out so I put some thread sealer on it and tightened it back. When I checked the rest of them to see if they were on tight on of them was in but just kept turning without catching. I now have to tap it to a 7/16th and upgrade the bolt as well. My question is about the metal shavings that might get pushed up into the housing where the gear case and leg are bolted together with this bolt. Are these shavings going to tear anything up? What exactly is up in there? Water was coming out of the other bolt so I am assuming that these metal shavings will get pushed out through the water cooling system. Any insight?

 

[roscoe]

Re: Upper Gear Case bolted to Leg

Drill it, tap it.
Then you can remove the gearcase and clean out any metal shavings.

While you have it open, change the water pump impeller.

 

[cpbrocke]

Re: Upper Gear Case bolted to Leg

man do i feel stupid. The one bolt that I thought was leaking actually wasn't. Upon closer inspection there is a tiny drain right behind it for the water left in the impeller after the engine shuts down, I'm guessing. And using a handy twig the hole that I had to tap up a size actually doesn't go through. But the bolt doesn't slip anymore and I don't have to take it apart to clean it out. Never tapped anything before, sure is a handy tool.

 

[Frank Acampora]

Re: Upper Gear Case bolted to Leg

If you never tapped anything before, Follow this procedure next time. Aluminum tends to gall and there is a distinct possibility of breaking the tap--especially in smaller sizes. To avoid this:
1. Be sure that the hole is the correct size for the tap.
2. Use plenty of a tap cutting lubricant- if you don't have any and don't want to buy it, oil will do in a pinch.
3. Only turn the tap 1/4 to 1/2 turn then back it out a bit. Do not force it. Eventually you will get a "feel" for the correct amount of pressure to use. Repeat the process until the hole is tapped to the correct depth. every couple of turns, bach out the tap fully and clear chips from the flutes.

Takes a little longer this way but pays off in less ultimate aggravation.