1994 Merc 225 Compression/Head Gasket Question

[gw204]

Been talking to guy about a 1994 Merc 225 that he has for sale. The motor was advertised as in running condition but with a bad lower unit (which I've already located a replacment for). A recent compression check (not done by me) revealed numbers "around" 105 the left side and 91, 90 and 39 on the right. From searching the forum, it sounds like the 105 is pretty normal for a carbed motor.

So my question is, what are the chances the lower numbers are due to a bad head gasket? That was my initial thought because the low cyls are all on the same side.

I'll know more once I go check it out for myself, but I was just wondering if that's feasible.

Thanks.

[gw204]

Well, I think I just answered my own question.

I knew the later 3.0s used o-rings in the heads instead of gaskets but it looks like that was actually in place since the 3.0 was introduced.

[muskamoot]

Not likely to be a head gasket,although it's possible.Head gaskets tend to leak between 2 cylinders with a monohead and you only have 1 low cylinder if it's an oring setup, you could have a bad oring..I have the same engine and have 120 on all 6.