Originally Posted by Rocinante33
I am looking for a replacement now and am wondering whether a 2QM 20 would fit in the same space and provide a little HP boost as well. The specs look very promising, but has anybody actually made this swap?
I have had a couple of 2GM20 engines and currently have a 2QM20.
In your situation, I think you would be better off with the 2GM20.
The QM is a very different engine to the GM and while I think the QM is better engine overall, it is very very heavy and a little bigger than the GM. In fact it is about 100Kg heavier or put another way - about twice as heavy.
IMO, the QM will outlast the GM and achieves it max hp at 2800 rpm
compared to 3600 for the GM. The QM has wet liners and then GM does not have replaceable liners.
IMO the GM is best suited in a recreational sailboat while the QM is best suited for small workboat.