Black soot on stern from exhaust ..

[Bodach na mara]

Same problem, but only happens when I get impatient and use too much welly. The real problem I suspect is that you are causing the engine to labour a bit. Squatting may indicate an attempt to drive the hull above the displacement speed limit. Labouring can also be caused by a prop that is over-sized, but you knew that anyway.

The real cure is a lighter touch on the throttle or a more powerful engine.

 

[Refueler]

[ QUOTE ]
Same problem, but only happens when I get impatient and use too much welly. The real problem I suspect is that you are causing the engine to labour a bit. Squatting may indicate an attempt to drive the hull above the displacement speed limit. Labouring can also be caused by a prop that is over-sized, but you knew that anyway.

The real cure is a lighter touch on the throttle or a more powerful engine.

[/ QUOTE ]

25ft Motor Sailer .... Perkins 4-107 @ 42HP ... enormous great prop suited to engine and hull ..... hits 9kts within sec's ! Seriously - it accelerates AND stops like a Ferrari !

The soot is expected for old engine, sh**e fuel, ...... what I'm looking for is any way to stop it sooting up the transom ...