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Two cylinders down
Hi, Afourians -
I get no compression in the first and second cylinders nearest the flywheel and farthest from the exhaust. I checked that the valves were closing properly and all appears to open and close desirably.
We put MMO into the first cylinder when its valves appeared closed, let that soak overnight, turned the engine, let the other set of valves soak, tapped on the valves from above with allen wrenches, moved the valves by hand via the access panel behind the carb, and moved the springs around a bit with vice grips. All seemed similar to the working valves. While we were there, we calibrated to spec the clearances between cam and valves. We did compression tests between all these fiddlings. Still zero.
EXCEPT we got 30 psi when we tested immediately after putting some MMO into #1. It couldn't be replicated in #2, and #1 returned to zero after sitting briefly.
Then we ran the engine to heat it up, let her run with throttle completely open for a few minutes, much to the chagrin of our marina neighbors, and 1 and 2 weren't firing. My friend DID seem to notice a slight hissing sound in the vicinity of those two cylinders as if air was escaping somewhere, although we couldn't tell where.
I've attached a photo of the engine. Perhaps its general setup could give you some clues.
Looking forward to helpful advice!!
I get no compression in the first and second cylinders nearest the flywheel and farthest from the exhaust. I checked that the valves were closing properly and all appears to open and close desirably.
We put MMO into the first cylinder when its valves appeared closed, let that soak overnight, turned the engine, let the other set of valves soak, tapped on the valves from above with allen wrenches, moved the valves by hand via the access panel behind the carb, and moved the springs around a bit with vice grips. All seemed similar to the working valves. While we were there, we calibrated to spec the clearances between cam and valves. We did compression tests between all these fiddlings. Still zero.
EXCEPT we got 30 psi when we tested immediately after putting some MMO into #1. It couldn't be replicated in #2, and #1 returned to zero after sitting briefly.
Then we ran the engine to heat it up, let her run with throttle completely open for a few minutes, much to the chagrin of our marina neighbors, and 1 and 2 weren't firing. My friend DID seem to notice a slight hissing sound in the vicinity of those two cylinders as if air was escaping somewhere, although we couldn't tell where.
I've attached a photo of the engine. Perhaps its general setup could give you some clues.
Looking forward to helpful advice!!
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