Quick & easy Q- that's the proper compression for a 2004 Merc 15hp?

[Jjmkerr]

Any and all info Much appreciated!!

Ps any way to confirm it a15 other then the cowl & serial plate? Mid section looks more weathered then the top, as if someone swapped it out the middle section (including the serial plate) and added a new 15hp cowl. Thx!

 

[JB]

Re: Quick & easy Q- that's the proper compression for a 2004 Merc 15hp?

Proper compression is both cylinders within a 10% span. Rope start engines may compress as little as 60-70psi, electrics 90 or so. The important number is the difference between the cylinders. . .10% or less. Typical engines compress over 100, but that is not required.

Use the procedure in the Engine FAQs ^^^.

 

[Jjmkerr]

Re: Quick & easy Q- that's the proper compression for a 2004 Merc 15hp?

Thx for the reply .
Two stroke, Engine was warm, took both plugs out, made sure the kill switch was set to off, pulled the choke out, pulled the throttle swing arm to the full throttle position, plugged the compression tester in, and gave the cords a half a dozen pulls, then tested the other. Got 120 in each +/-2. Figure that's good, but Just curious how good? Just bought this engine, some I'm really curious. It seemed to run well when I tested it but it did take the water a couple minutes before it started to come out.