[chris vella]

hi, today i bought a 1997 mariner v6 150 with Carburetors, is there someone who can tell me what is the correct compression for the 6 pistons please?

[CharlieB]

Between 125 and 135, depending on the head gasket thickness. As long as all cyl's are very close to even, less than 10% variation, it should be fine.

Some have the heads milled/planed to raise compression to 145 to gain a bit more performance. Not really recommended for the average boater as fuel quality, ignition timing can become issues.

Generally kept stock as a rock is just fine.

[chris vella]

thanks very much

[mxzer29]

I have a 94 EFI(magnuim), mine were 135 all six cyliners.. Great motor!