Originally Posted by
steve111
7000 rpm is way low for any of the props you mention
Steve
Not if its running backwards and this is exactly the problem that I had with my rebuilt Marz diesel ............. and it had pretty much the same induction system.
The cause was a broken back plate gasket that was bleeding air into the lower crankcase at the wrong time.
Every time Greggles got it going it was happily running backwards but at a much reduced rate on knots.
Perhaps this is the issue here?
Quick question here, with no tach available how do you know its running at no more than 7000 rpm?
Harmonics perhaps?