I have the 3GM30F on my 35/3 and a MaxProp feathering prop. I get to 3600 RPM, cruise at 2800. I think it is a 16 inch set at 14 degrees, but can look it up.
Joel On Tue, Jul 21, 2015 at 10:31 AM, Nauset Beach via CnC-List < cnc-list@cnc-list.com> wrote: > John, Mike and any others with a Yanmar 3GM30F > > What is the make, diameter and pitch of your props, and can you get to the > one hour rated RPM of 3600? > > Back in 2010 I had an engine overheat alarm and discovered the coolant > overflow tank was full and had an amount of oily substance mixed in. There > was very little coolant left in the engine. The mechanic discovered a > blown > head gasket was the cause. The head was sent to a shop to be "rebuilt" and > a few other parts replaced. > > Last month [just after Edd's engine woes came to light] I had another > overheat alarm, and again discovered the coolant tank full and the same oil > mix. Am assuming the head gasket is blown - again. The mechanic has not > looked at it yet. Obviously, something is "wrong." > > The July edition of Cruising World had a timely article about props and > stated an over pitched prop puts additional wear on the engine and can lead > to cavitation. Nothing new there but started a possible theory. I have > not > had dark exhaust so did not think the prop was over-pitched, but there is > some pitting on the prop blades so maybe there is cavitation and an over > loaded engine. Also have excessive vibration so the clues seem to be going > in that direction. I rarely take the engine up to 3000 RPM though did have > a several hour delivery at 3200 this spring. Have never tried but do not > think I could get up to 3600. [Have read the Yanmar tach's are not all > that > accurate and have not had the RPM's verified independently.] Still this > seems to be another indicator the prop may be over pitched. > > I originally had a Martec folding 16 D x 14 P prop though after the lack of > much reverse led to a "near miss" incident I replaced it in 2002 with a > Flex-O-Fold with a 16 D x 13 P at the recommendation of Flex o Fold. The > reduction is 2.61. Am thinking the increased surface area Flex prop is > overloading the engine even though the pitch was decreased by 1" compared > to > the Martec. > > Anyone have any thoughts? > > Thanks, > Brian > > -----Original Message----- > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Hoyt, > Mike via CnC-List > Sent: Tuesday, July 14, 2015 12:39 PM > To: cnc-list@cnc-list.com > Cc: Hoyt, Mike > Subject: Re: Stus-List Best Engine? > > We have Yanmar 3GM30F in our Ferrs 33 which is similar hull shape to > C&C33-2. We make 6.2 at 2300 RPM and can just squeak out 7.0 at WOT > > Mike > Persistence > > -----Original Message----- > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of John > and > Maryann Read via CnC-List > Sent: Tuesday, July 14, 2015 8:19 AM > To: cnc-list@cnc-list.com > Cc: John and Maryann Read > Subject: Re: Stus-List Best Engine? > > HI Brian > > Our 34 has the Yanmar 3GM with Martec folding prop. Clean bottom cruising > is 5.5, max is about 6. As I recall, your max speed is supposed to be > about > 80% of theoretical hull speed with throttle wide open?? Another variable > is > the calibration of the knotometer and if using the GPS the impact of > current > > > John and Maryann > Legacy III > 1982 C&C 34 > Noank, CT > > > ----- Original Message ----- > From: "Brian Morrison via CnC-List" <cnc-list@cnc-list.com> > To: <cnc-list@cnc-list.com> > Cc: "Brian Morrison" <brianm...@hotmail.com> > Sent: Tuesday, July 14, 2015 00:47 > Subject: Stus-List Best Engine? > > > > Hello, > > > > I often sail with a group of sailors that have more modern and > > somewhat larger boats than my 1979 C&C34. When there is no wind and we > > are forced to motor I have difficulty keeping up. With a clean bottom > > my cruising speed is about 5-5.5 knots. I have an Atomic 4 engine. I'm > > wondering would > > > a Yanmar or a Westerbeke give me 7+ knots? > > > > Brian C. Morrison > > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > -- Joel 301 541 8551
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