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Compression probs. Had compression and now none? 1957 10hp

N

newbe25

Member
I have a 1957 10hp Johnson Seahorse. I bought it and It had compression on both cylinders in the 60's. But it needed all new gaskets and impeller. So I took it apart and replaced the head gasket,exhaust gasket and the powerhead gasket, and the impeller also I cleaned out the carburator. Put it all back together and checked the compression before I put gas in it to start it. And I am getting no compression at all on my gauge???. I tried to start it anyway and it back fired once so I just left it alone and came inside. Thanks for any advice as to why this happend or what to check. Thanks. It had compression before I replaced the above. I used the same gauge. So I am off to tinker some more. The gauge is only 2 days old. I used it on my 5.5 hp 1954 Johnson and it worked. Plugged in to 10hp and no compression.
 
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Re: Compression probs. Had compression and now none?

Can you physically "feel" compression when you crank the engine over via the manual starter? If not, I'd strongly suspect that you have the wrong head gasket installed.

Head bolts must be torqued in the following sequence (I don't have the actual bolt torque specs in front of me).

9...10
5....6
1....2
4....3
8....7

Backfired? Did you have the flywheel off? If so, possibly either the flywheel key sheared... OR... you might have neglected to install the key or torque (even tighten) the flywheel nut? This brings up the possibility that the flywheel is simply spinning on the crankshaft taper and the crankshaft is not moving (weird things do happen).

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store
 
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