Tried to do a compression test on a 2000 year model 90hp Mercury today, but when we tried to screw in the tester it bottomed out before it reached the threads, we couldn't even get the first thread on. I been looking online for some sort of adapter or a test kit with longer body with more threaded area but so far no luck. Does anyone know if there's one out there or would I have to wait until a Mercury dealership is open to see if they have one?
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Not sure I understand what you mean "bottoned out". My compression gage is all threads. -
I can't get the pic to load with this dang malware.. but mine looked just like a sparkplug with a shredder valve instead of an electrode.Comment
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Here’s mine. The threaded area needs to be longer. When I inserted it where the spark plug was the threads in the cylinder block I are so deep the tester wouldn’t reach the threads.
I hope that explains it a little better.Attached FilesComment
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Most compression testers come with different adapters that screw onto that hose end that i am seeing. The adapters come with different thread sizes and depths to fit different engines.Comment
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Check that spark and see if there's a heli-coil that might have come out with the plug. I've never heard of your situation.Comment
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Go get your money back from Harbor Freight. Borrow a tester from OReilleyComment
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Any updates??Comment
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No sir. Back at work today so may be a day or two before I get back on it. I’m gonna see if the compression tester that ORiellys has is any different from the one I haveOriginally posted by Walker View PostComment
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Compression testers are compression testers. My bet is the threads in your head are gone. Someone over tightened the plug and stripped the threads. Being as loose as you describe I bet there's a heli-coil the came out with the plug. I've never worked on a mercury or any other outboard that had recessed threads.Comment
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