Yanmar 3QM30 Cooling

[gts1544]

Gents & Ladies, I am looking at a 1979 Yanmar 3QM30 in a boat on E-bay and am wondering if it is raw water or fresh water cooled and how to tell by model number? Also, if it is raw water cooled, what has been their history in salt water? Any help in preventing my making a mistake would be appreciated. Thanks. George

[never monday]

no real way to tell without looking at the motor. Some were FWC conversions also.
3QM is a large heavy engine. That is getting long in the tooth for spares. It may end up being a penny wise / pound foolish choice.