87 351W Rear Main Seal Leaking

I have a leaking rear main seal on my 87 351W Nautique and was wondering if anybody has dealt with this. I spoke to a engine repair place locally about doing work on the engine, and was pleased to hear that he has done a couple over the past 3 years. He even knew that they were reverse rotation engines! He said he wouuld do it($800) if I could get him the parts. Any help on what all is needed, and where to go to get it would be greatly appreciated. When pulling the engine, does it mess up the seal on the prop shaft? On a 22 year old boat that has some leakage, should I deal with that shaft seal at the same time? What parts would I need for that? I am rather new to this site, but have marveled in the depth of experience and knowledge that is shared and posted. Thanks.

Rock,

At the end of the transmission there is a coupler with four bolts. This disconnects your drive Shaft from the Motor and Transmission. a about 6 inches down is a packing gland. It is a brass item that has a little rope packing in it. That packing keeps the water for coming into the boat. However, you need to adjust it so that it drips about 3 drips per minute. This packaging need water to keep cool. Companies ( OJ) makes a drip less packing. You need to do some forum search on repacking gland and adjusting the packing. If I had the motor out, I would want to change the cutlass bearing or bushing that is in the strut under the boat.

The Ford Marine Engines use a split or two part seal. This is why they have a history of leaking. I am going to pull my engine this winter and fix my leaking seal. I will also pull my drive shaft and check it to see that it is straight. I am also going to change my cutlass bushing or bearing. Go to www.skidim.com and you can see picture of many of these parts on their online catelog and it will teach you a lot about how your boat works.

If water is coming into your boat it may be coming in aroung your rudder. It also has a packing glad that needs packing. You tighting the rudder glad very tight and the drive shaft glad is not tightened very tight. Too tight will burn up the packing. Another source of water is old mufflers or leaking exhaust hoses.


I hope this helps,

Donald

The trouble you might have is finding a seal, I hear they are getting scarce. Check with a site sponser, Karen at Correct Parts, they are on the lower left of this page. Also check the archives, the motor does not have to come out to do this repair,just the trans.

Our local Transmission shop quoted me 150 for the seal and labor.

I appreciate all your help. From what everyone has responded it looks as if I probably could tackle this myself. Can anyone give me verification that I will not have to pull the engine to do this on a '87 Ski Nautique with a 351W PCM. Having to pull the engine would be a deal breaker with my garage set-up, and Iowa's winters.

Somewhere on this site there was pictures of how to support the motor while you pull the trans. I tried to find them but could not. Pete, anyone? Those pictures would really help show you how to do it. Makes you appreciate a Holman Moody

I know Johns (Jbear) son did his rear main not too long ago. I do believe he used the jack method under the manifolds to get the engine high enough to do the job. thread on Dennis doing John's rear main


BTW, where have you been Jbear??? I thought since you've moved to Florida you no longer go into hibernation!!

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=12716&KW=rear+main+seal&title=tranny-removal

This is my thread from last year. It may be of some interest. My boat is a 95 and at the time had all the protec ignition that was a pain to work around. Yours should be much easier. I am only going to tell this part of the story b/c I like this site more than my reputation:

Originally, I thought the tranny was leaking, when i got into it I found the leak appeared to be from the rear main seal. Being the cheap/stubborn sob I am, I bought a seal from the auto store, compared them, then decided they were very similar and i went with it. I recently noticed some oil around the bell housing. I cant say for sure wether the seal is leaking again, or if I just missed the original leak. I may tackle it again this winter.....so, long story short, I think I would go with the marine/pcm seal to be on the safe side. There, I said it! I feel a lot better now.

87 351w has a one piece seal skidim.com to purchase the correct one for your right hand rotation engine. be sure to use a thread sealant on the flywheel bolt or it will leak oil from there. you don't have to remove the engine to replace just the transmission, damper drive plate and flywheel. be sure to make the flywheel so you put it back on the same for balance. the seal will be visible once you remove the flywheel. you can pop it out with a flat head screwdriver . be careful not to nick the crank surface. take the new seal and tap carefully into place and reassemble. You can support the engine with a block of wood while doing the work. As for the cutlass bearing and shaft seal you will need to have the boat on land. I cut my cutlass bearings in half legnthwise and then knocked it out with a hammer and cold chisel. some unit have a set screw holing them in the strut my did not. once the old ones were out clean up the surface to make way for the new. using a block of wood and a hammer carefully tap the new bearing into the strut. Shaft seal replacement undo the coupling nut dig out all the old pieces probably 3 then take the new material and cut 3 or 4 pieces just long enough to wrap around the shaft to have the ends meet. then place them into the coupling staggering the ends and hand tighten the coupling nut. final allignment and tightening should be done in the water. since the tranny came out the coupling will need to be propperly aligned once boat is in the water with a fair amoutnt of fuel in the tank so the hull will settle properly.