Yes, the prop looks great and feathers and unfeathers very smoothly and easily by hand. One thought that occurred to me is that the max prop might have been assembled incorrectly, with one blade set to higher pitch than the other. In the assembly process one has to match the gear on each blade to the correct tooth on the gear in the hub. But one would hope that they'd have gotten that right when they re-assembled after the prop was rebuilt. Anyway I plan to check blade pitch among other things.
On Thu, Jan 9, 2014 at 1:02 PM, Joel Aronson <joel.aron...@gmail.com> wrote: > Bill have you tried to rotate the prop to see if the blades rotate > smoothly? Can you borrow a different prop for a trial? I agree an inch is > crazy! > > On Thursday, January 9, 2014, Fair, Mike wrote: > >> I chased a strong vibration for 3 years. In the end it caused my shaft >> seal to leaks and rust out my oil pan and it broke a engine mount. In the >> end I filann7 disassembled my gori prop and found that there was a 2 ounce >> difference between the blade weights. Cost me $70 to balance and new mounts >> and I was purring again. >> >> >> >> Thanks, >> >> >> >> Mike Fair >> >> 413.587.6535 >> >> >> >> *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of >> *William >> Hall >> *Sent:* Thursday, January 09, 2014 12:46 PM >> *To:* cnc-list >> *Subject:* Stus-List Vibration >> >> >> >> Dear List, >> >> >> >> I've been troubleshooting quite a vibration problem since I got my boat a >> year and a half ago. I had hoped it all just needed an alignment, but that >> does not appear to be the case. I'm hoping that if I present the situation >> someone on the list may be able to point me in the direction of a fix! >> >> >> >> The boat is Starfire, my 1985 C&C 37. It has a Yanmar 3HMF. I believe >> it's the original engine, but was overhauled a few years ago. The previous >> owner said it was overhauled because it was no longer producing enough >> power. >> >> >> >> The engine drives a 2-blade max prop. There's a line cutter on the >> shaft. There's an R&D marine elastomeric coupling between the end of the >> prop shaft and the engine drive shaft. >> >> >> >> When I bought the boat, we noted a lot of vibration when in gear above >> about 1800 rpm. The surveyor thought it needed alignment and noted as well >> that the max prop had more play in it than it was supposed to. I hauled it >> that first winter, had the max prop sent back to max prop for overhaul, had >> new cutlass bearing installed, and when it all came back together in the >> spring found the same vibration as before. When running in forward, the >> prop shaft deflects significantly at higher RPM's (maybe 1" of wobble at >> the worst point along the drive shaft), and things shake in a way that >> can't be good. In neutral, as well as reverse, it runs smooth as silk >> right up into high rpms. >> >> >> >> I've since had a few engine / drive people look at it and try to figure >> it out. The shaft appears to be true. The alignment appears to be right on, >> as measured by two different mechanics. The elastomeric coupling was a bit >> worn, so we put a new one in. The engine mounts are substantial and seem >> good. The engine people think there's something wrong with the prop that >> the overhaul didn't fix. >> >> >> >> What does the list say? Is it the prop? Could there be something wrong in >> the transmission, say a thrust bearing or something? In flat calm I can >> get almost 5 knots without too much worry of breaking things, but into a >> sea or wind I'd really like to have the option to use more power. What >> would you try? >> >> >> >> Thanks in advance for the thoughts. >> >> >> >> Regards, >> >> Bill >> >> >> >> 1985 C&C 37 - Starfire >> >> Stamford, CT >> >> >> >> -- >> William D. Hall, Ph.D. >> 203 653 2886 (o) >> 617 620 9078 (c) >> wh...@alum.mit.edu >> > > > -- > Joel > 301 541 8551 > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com > > -- William D. Hall, Ph.D. 203 653 2886 (o) 617 620 9078 (c) wh...@alum.mit.edu
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