here's a link from MJ's issue with his

http://www.wellcraftv20.com/communit...ead.php?t=7580

ok tool time

this is a V4 motor but same exact part as V6

here's the valve

http://i8.photobucket.com/albums/a46...MVC-001S-5.jpg

here's where it gets water from when it's under 3000 rpms

http://i8.photobucket.com/albums/a46...MVC-002S-5.jpg

here's where it is going to under 3000 rpm

http://i8.photobucket.com/albums/a46...MVC-003S-5.jpg

here's where it goes above 3000 rpm out to the pisser on the lower housing from the above pic

http://i8.photobucket.com/albums/a46...MVC-021S-1.jpg

here it is under 3000

http://i8.photobucket.com/albums/a46...MVC-018S-1.jpg

here's above 3000

http://i8.photobucket.com/albums/a46...MVC-019S-1.jpg

first you need to remove below screws and nuts

http://i8.photobucket.com/albums/a46...MVC-009S-3.jpg

http://i8.photobucket.com/albums/a46...MVC-010S-3.jpg

then GENTLY pull out on the throttle arm till pin is out of the valve

http://i8.photobucket.com/albums/a46...MVC-011S-2.jpg

now GENTLY pull out till accessible

http://i8.photobucket.com/albums/a46...MVC-012S-2.jpg

now mark a location of the center part to out side so you replace correctly then pull out slide pin

http://i8.photobucket.com/albums/a46...MVC-013S-2.jpg

then pull out the insert carefully

http://i8.photobucket.com/albums/a46...MVC-014S-1.jpg

heres the valve taken out

http://i8.photobucket.com/albums/a46...MVC-016S-1.jpg

clean this part very well

http://i8.photobucket.com/albums/a46...MVC-017S-1.jpg

here's the inside of the valve with a seal in this ones case some have o-ring

http://i8.photobucket.com/albums/a46...MVC-015S-1.jpg

you can grease the rubber seal if in good shape and then light grease on the valve and reinstall usually stops the leak.


or you can use the cap covers as below better to use the bypass system

http://i8.photobucket.com/albums/a46...MVC-004S-4.jpg

If you have the white housings, DITCH THEM IMMEDIATELY! OMC issued a bulletin years back about overheating caused by the white housings. The white t-stat housings have a guide on the end of them to help center them in the seat, but all it did was cause overheating as the rubber got older in the seat and wouldn't let them move out when the valve would drop pressure. The black housings are the only housings you are supposed to use now. Inside they both use the same vernotherms, and open and close at the same temp. Clean out the valve that SKOOLS posted, and make sure the linklage is hooked up working to it. Next get a set of the black t-stats and diaphrams and your problems will most likely be over. Also the stats should open up at 160, so it sounds like the springs inside your stats are work hardened from the years anyways. Also pay attention to how the valve comes apart as the valve can be installed 180 degrees out and it won't function properly that way.

skool

Thanks for all your help, got it under control for now. Do you know the part number to the black thermostats? The cooler stat. The parts guy thinks i'm crazy when i told about it.

Thanks Again

You guys rock, Thanks for all the post. I do not have my V-20 anymore but I still feel like part of the Family.

Thanks Again,
Great Eastern

The housings are different, but the vernotherm inside will be the same. You want the black housings though as the white ones are nothing but trouble. The parts you need are 2 0394408 DIAPHRAGM, Thermostat cover and 2 0434137 THERMOSTAT ASSY. Once you have the updated housings you can just replace the vernatherms in the future for alot less money.