I asked this in a facebook forum and got some interesting answers but want your input:
Any ideas why all four cylinders would drop in pressure when tested cold? Previously had a solid 120 but now all cylinders read right around 60.
I brought the boat out of winter with great success but the other day on a long sail coming out of an inlet it started dying as the boat pitched with the waves. I suspected back pressure since the exhaust was plunged under the water with those waves. Had a few runs where the engine died with little indication of why. Dying when at idle was particularly repeatable. The next morning, the engine had a lot of difficulty starting. Cleaned off some very sooty spark plugs when it sounded like I had a misfire. Compression test of all cylinders and spark test sat but the pressure in all four was about 60psi.
Fuel level was almost full.
Eventually I got her running and got out of the marina confidently on flat water with throttle.
Thoughts?
Any ideas why all four cylinders would drop in pressure when tested cold? Previously had a solid 120 but now all cylinders read right around 60.
I brought the boat out of winter with great success but the other day on a long sail coming out of an inlet it started dying as the boat pitched with the waves. I suspected back pressure since the exhaust was plunged under the water with those waves. Had a few runs where the engine died with little indication of why. Dying when at idle was particularly repeatable. The next morning, the engine had a lot of difficulty starting. Cleaned off some very sooty spark plugs when it sounded like I had a misfire. Compression test of all cylinders and spark test sat but the pressure in all four was about 60psi.
Fuel level was almost full.
Eventually I got her running and got out of the marina confidently on flat water with throttle.
Thoughts?
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