I Have Just Got An Old Mi 21 The Boat Has An 90 Hp 2 Stroke Engine It Runs Fine And The Boat Goes Well But Im Thinking About An New Engine Can Anyone Tell Me What Engines Tthat Are Fitted To There Mi 21 Boats Many Thanks
I have the volvo penta AD31P 150hp turbodiesel with duoprop drive on mine - clean and empty she does 32 knots flat out, currently it's 28 with plenty of kit, 2 passengers and props with blistered paint - I'd expect 30+ with clean props and removal of the odd barnacle on the hull.
Guy moored near me has a new Pirate 21 (slightly deeper hull at the transom) with a honda 135 4-stroke and claims similar performance. He was thinking of the 175, but it's a bigger, heavier block. Weight in the stern of an MI really hurts performance, so I reckon he's got just about the perfect outboard, the only other option would be a similar E-tec if you want a two-stroke.
Edit - if you have a commercial fishing license on the boat then you may be restricted as to how much power you can have.