My first V20

[scook]

You pretty much have the same engine that I have. I’m guessing you have the same problem I had - that the rear seal in the internal water pump is bad. To keep coolant from getting into the engine at the end of the camshaft, there’s a weep hole that lets it drip into the bilge (the water pump is driven by the very front end of the cam.

It’s a pretty big pain to get into it to fix it but if you’re a fair mechanic and a glutton for punishment, you can do it. On mine, the shaft was galled and I had to find a repair sleeve that press fit over the galled section of the shaft. I screwed up the first seal I put in and had to do it all over.

I have manuals but our resident boat mechanic, Spareparts saved me from shooting myself when I was fighting some pesky locating pins that wouldn’t let me get the cover back on. He a very generous guy with his knowledge and will probably chime in when you have problems.

If you find the weep hole and it’s the problem (probably won’t leak until it gets warm enough to build some pressure) and don’t find a manual, I’ll see if I can find the applicable pages and scan & email them to you. I have also had fair luck finding blow up diagrams and even manual sections by Googling around for them, so you should try that first.

Regarding the rusty bolts, I had that problem and it diminished a lot when I fixed the coolant leak so the engine compartment wasn’t so humid. I think the humidity builds up and then condenses when the engine cools off, rusting the bare metal bolts. That’s speculation but it fits pretty well.

It’s a good wintertime project.

[Pipe_Dream]

Originally Posted by scook

You pretty much have the same engine that I have. I’m guessing you have the same problem I had - that the rear seal in the internal water pump is bad. To keep coolant from getting into the engine at the end of the camshaft, there’s a weep hole that lets it drip into the bilge (the water pump is driven by the very front end of the cam.

It’s a pretty big pain to get into it to fix it but if you’re a fair mechanic and a glutton for punishment, you can do it. On mine, the shaft was galled and I had to find a repair sleeve that press fit over the galled section of the shaft. I screwed up the first seal I put in and had to do it all over.

I have manuals but our resident boat mechanic, Spareparts saved me from shooting myself when I was fighting some pesky locating pins that wouldn’t let me get the cover back on. He a very generous guy with his knowledge and will probably chime in when you have problems.

If you find the weep hole and it’s the problem (probably won’t leak until it gets warm enough to build some pressure) and don’t find a manual, I’ll see if I can find the applicable pages and scan & email them to you. I have also had fair luck finding blow up diagrams and even manual sections by Googling around for them, so you should try that first.

Regarding the rusty bolts, I had that problem and it diminished a lot when I fixed the coolant leak so the engine compartment wasn’t so humid. I think the humidity builds up and then condenses when the engine cools off, rusting the bare metal bolts. That’s speculation but it fits pretty well.

It’s a good wintertime project.

Great info for Dschaffer! Help like this is what makes this such a great site.

[Dschaffer]

Originally Posted by scook

You pretty much have the same engine that I have. I’m guessing you have the same problem I had - that the rear seal in the internal water pump is bad. To keep coolant from getting into the engine at the end of the camshaft, there’s a weep hole that lets it drip into the bilge (the water pump is driven by the very front end of the cam.

It’s a pretty big pain to get into it to fix it but if you’re a fair mechanic and a glutton for punishment, you can do it. On mine, the shaft was galled and I had to find a repair sleeve that press fit over the galled section of the shaft. I screwed up the first seal I put in and had to do it all over.

I have manuals but our resident boat mechanic, Spareparts saved me from shooting myself when I was fighting some pesky locating pins that wouldn’t let me get the cover back on. He a very generous guy with his knowledge and will probably chime in when you have problems.

If you find the weep hole and it’s the problem (probably won’t leak until it gets warm enough to build some pressure) and don’t find a manual, I’ll see if I can find the applicable pages and scan & email them to you. I have also had fair luck finding blow up diagrams and even manual sections by Googling around for them, so you should try that first.

Regarding the rusty bolts, I had that problem and it diminished a lot when I fixed the coolant leak so the engine compartment wasn’t so humid. I think the humidity builds up and then condenses when the engine cools off, rusting the bare metal bolts. That’s speculation but it fits pretty well.

It’s a good wintertime project.

Thank you for the great info. Unfortunately, I don’t have a garage to store the boat where I could work on it this winter. I will likley be winterizing it this weekend and leaving it be until the spring. I am mechanically inclined but would prefer to find someone in the area that is firmiliar with these motors. I have been searching for a manual (88 mercruiser 3.7) and a lot of information comes up about the 470. Is it the same motor? Mine does not say 470 on the top of the motor like others I’m seen. It say 3.7. I want to be sure I am looking for the right thing. Thanks again for your help.

[scook]

Hey Spareparts, when you’ve survived the storm, can you verify whether I’m correct.

I believe the 3.7, the 470 and the 170 (that’s mine) are all the same engine. Yours looks exactly like mine from what I can tell from your pictures.

It was a project to do but it was satisfying to beat it into submission and I knew my engine a lot better when I was done. I made a puller to remove the harmonic balancer (crankshaft pulley), which also carries the magnets for the integrated alternator. That worked fine and I was able to clean up the alternator (which later died anyway) and that gave access to the cover that houses the water pump and then the fun really began. I’m pretty busy right now but if you can’t find a manual, I’ll look in mine and see what I can find to pass along.

Whatever you do, don’t forget to drain the heat exchanger if there’s any chance of freezing - I mentioned that before - it’s an expensive mistake that I made.

[Dschaffer]

Originally Posted by scook

Hey Spareparts, when you’ve survived the storm, can you verify whether I’m correct.

I believe the 3.7, the 470 and the 170 (that’s mine) are all the same engine. Yours looks exactly like mine from what I can tell from your pictures.

It was a project to do but it was satisfying to beat it into submission and I knew my engine a lot better when I was done. I made a puller to remove the harmonic balancer (crankshaft pulley), which also carries the magnets for the integrated alternator. That worked fine and I was able to clean up the alternator (which later died anyway) and that gave access to the cover that houses the water pump and then the fun really began. I’m pretty busy right now but if you can’t find a manual, I’ll look in mine and see what I can find to pass along.

Whatever you do, don’t forget to drain the heat exchanger if there’s any chance of freezing - I mentioned that before - it’s an expensive mistake that I made.

Thanks again for the insight. If there are any “must use” write ups on this repair, please let me know. Also, any sources for parts would be nice. If there is anything else I should do while I’m in there as preventative maintenance, I would appreciate the heads up. Thanks again to all who have chimed in.

[cfelton]

Hey D, look up Sterndrive.com, Mercruiser 3.7 coolant leak. Its pretty good info for what you're getting into. I had to replace my seals and pump cover gasket once. Wasn't too bad. My camshaft was ok not grooved, just the seals were old and had hardened from sitting up. I did it in an afternoon, you can do it! Scook is on the money with sleeving the camshaft if its grooved, its been done with good success. I had found some info on sleeves and seals but just needed seals. I'll try to dig up some info on seals and sleeves for you when I get off nights at work.

[cfelton]

Ebasicpower.com had the parts you probably need. two cam seals FED471570 and a Cover Timing gasket kit @ 14.95. Check em out, they deliver fast!

[scook]

A comment about getting the seals in place over a sleeved camshaft. There are a couple of locator pins sticking out of the engine to locate the cover when you put it back on and I screwed up one seal fighting those pins. Spareparts advised pulling them out and replacing them after the cover was in place - it saved my sanity, what there was of it to start with. One of the pins REALLY didn’t want to come out but several days of applying penetrating oil (I don’t recall what I used- may have been Kroil but use the best stuff you can find),I finally got it. Grabbed on with vice grips (the pins were so hard that the pliers didn’t make even a scratch), harfed up and down, more penetrant, over and over and finally it budged a little and I knew I had it - definitely the hardest part of the job.

By the way, I didn’t know the seal was screwed up until I took it out for a test run and it overheated again. Had to do the whole job again. Pull the pins and be very careful to get the seals in right the first time, particularly if you need to sleeve it.