Compression?

[getfished]

Not sure if this is appropriate forum for this query. I am considering purchasing a boat with a “350” Chevy inboard/outboard. I wonder if anyone can offer compression numbers on this type motor. I understand that the 10% variance may actually be the material factor to consider.

if I conduct a compression test, how is it done correctly ?

engine warmed up ?
pull all plugs prior to test or one at a time ?
what position should the throttle be ? Idle or full ?

any other things I should be on the lookout for as I consider this purchase ?

Thanks
steve

[howieranger]

A proper compression test is done with a fully warm motor and full battery with all of the plugs out and the throttle fully open. Be sure to disable the ignition circuit. Watch the gauge to note the max pressure reached and how much the pressure rises with the first couple of compression strokes.

[EuropeanAM]

+1

Done just like the thread in the FAQ indicates.

[getfished]

Thank you