"I have a 1987 5.0 OMC. Short
"I have a 1987 5.0 OMC. Short story is motor had blown head gaskets last year. I replaced and have been running boat for about 10-12 hours trying to get it running right. I went about troubleshooting a little backwards. Replacing wires, rotor, cap, points, plugs, ect. I finally did a compression test (which I should have done first). I had 145-150 on all cylinders, except #5. It had ZERO. I don't know how but the exhaust rocker for this cylinder was over tightened, leaving the valve open. I backed the nut off and re-adjusted the rocker correctly. I did compression test again and only had 60 psi. I sprayed a LOT of deep creep into the plug hole and cranked the motor, hoping to dislodge the carbon ect. from the valve seat. Another compression test shows 80-85. At this point I put it all back together and ran it while spraying deep creep through carb. It sounds much better and actually runs smooth now on muffs.
Question is: What do you guys think the long term outlook is. I will put it in the water tomorrow or friday to see how it does. Any suggestions or input would be helpful. Thanks, Matt"
"I have a 1987 5.0 OMC. Short story is motor had blown head gaskets last year. I replaced and have been running boat for about 10-12 hours trying to get it running right. I went about troubleshooting a little backwards. Replacing wires, rotor, cap, points, plugs, ect. I finally did a compression test (which I should have done first). I had 145-150 on all cylinders, except #5. It had ZERO. I don't know how but the exhaust rocker for this cylinder was over tightened, leaving the valve open. I backed the nut off and re-adjusted the rocker correctly. I did compression test again and only had 60 psi. I sprayed a LOT of deep creep into the plug hole and cranked the motor, hoping to dislodge the carbon ect. from the valve seat. Another compression test shows 80-85. At this point I put it all back together and ran it while spraying deep creep through carb. It sounds much better and actually runs smooth now on muffs.
Question is: What do you guys think the long term outlook is. I will put it in the water tomorrow or friday to see how it does. Any suggestions or input would be helpful. Thanks, Matt"