Slightly off topic.
When sailing, I been told to always keep the stopped engine in gear (forward or reverese) so the prop folds back quickly.
This doesn't seem right to me.
Has anyone else heard this?
Check your transmission manual.. most do say to put in reverse while sailing, some do not, incl Yanmar, and suggest you leave it in neutral. Hurth says not to let the prop freewheel while in forward gear..
Either way, stopping the shaft will promote faster folding.. sometimes an unfolded prop will continue to spin otherwise... same with feathering. If your transmission advises against leaving the gear in reverse, you can always just do it long enough to promote folding and then leave it in neutral afterwards.
My 1981 C&C 30 MK1 manual says 6.7 kt at 3400 rpms.
Well here is the thing the last owner put a folding prop on because he raced. I here a thud when I engage the prop. It donít back up very good. And I can only get around 2,000 rpms? If I push past that very long it starts wanting to smoke black smoke? Like ,I may be pushing too hard on the engine. any advice?
Sounds like you're overpitched.. a prop shop may be able to fix that for you and repitch your existing prop. btw that style of prop can sometimes only spin one blade open, causing a lot of vibration. If you find that happening get into the habit of giving things a quick spin in reverse prior to shifting to fwd.. seems to help. This mostly occurs when the prop comes to rest with the blades on a vertical axis, and one blade drops open due to gravity and lack of boat speed. The other blade, sitting in line with the shaft sometimes won't flip open leaving you with effectively a one blade prop - a very unbalanced circumstance!
The poor reverse performance is one of the costs of the reduced drag.. if you're not racing and want to avoid all this the Campbell Sailor prop is a good, relatively inexpensive option.