Tweet
womble378
I have a 1987 Yamaha 90 3cyl outboard. It recently developed a leak around the gasket under the thermostat housing. I have draw-filed both surfaces and replaced the gasket but cannot stop the leak. When I start the motor it takes about 30 seconds before it blows out. It appears to blow what seems like exhaust fumes as well as water. Should this area have exhaust fumes and what sort of pressure should be in the thermostat area. Looking forward to any pointers. Thanks :
-
-
draw file it all you wish.
until the surface finnish is at least a 32 and the flatness is less than .004" its gonna leak. -
womble378
Thanks so much for your reply. I finished it off with 1200 sand paper on a glass surface but sounds like I had better get smart and get a professional to do the job for me. Thank you againComment
-
womble378
Could you please give me the compression stats for 1987 90hp 3cyl Yamaha outboard. ThanksComment
-
stats are within 10 psi top to bottom.
surface flatness can be measured with a straight edge and a feeler guage.
not hard,can be done at home.
its time consuming at home.Comment
Comment