On Oct 19, 8:35 pm, Brian Whatcott wrote:
On Thu, 18 Oct 2007 11:22:19 -0700, druid
wrote:

Hi,

My new-to-me boat (Crown 28) has a Volvo 10hp MD6A, and it's way
overpropped with a Campbell Sailor 11x6 3-blade (gets 1500 WOT instead
of 2400). The Campbell Sailor dealer says his calcs recommend a 12x8
(ie much MORE pitch). Now, my experience with CS props is you take the
calculated pitch and subtract 2", but I donno...

Engine IS very "tired" but it pushes the boat at 5+ knots with the
over-pitched prop, so it can't be TOO bad.

Those with MD6A's - what prop do you have on it?

druid
http://www.bcboatnet.org

[based on 2 minutes back of the envelope and positively NO
experience with a MD6A]....
Borrow a 10 X 5 and look for 6+ kts at 2200 revs out of
your ol' tired engine.
:-)
Brian W

Interesting discussion - here's an "update":

First, I realized I have a spare prop: a 14x8(? have to look...) 2-
blade non CS (BTW, DON'T tell CS that their patented curve is simply
"cupping" ). I can maybe repitch it or just leave it as is - in any
case, I can put it on with a quick-lift rather than lifting the boat
out, leaving it on the hard while I remove the CS, get it repitched
and put it back on.

Second, I've decided to pull the head and injectors and try to squeeze
a bit more life out of the engine. Already got them off, getting them
to the rebuild shops on Mon, but 'er back together next weekend, and
see if I can get a few more RPMs. If not, I can still slap on the 2-
blade...

druid
http://www.bcboatnet.org