Dave,
When I spoke with Flex o Fold in April one potential source of vibration that was suggested [in addition to the others already mentioned in this thread] was how the prop hub was set on the shaft. The fellow said some times the key slips forward slightly as the hub is put on the shaft and the hub then rides up on it, making the hub / shaft combination slightly out of balance. I had originally dry fit the hub without the key and marked where it fit on the shaft, then put the hub on with the key. Had thought it was correct. I did get new blades [ 12 pitch vs the 13 pitch I was originally sold] and re-set the original hub on the shaft making certain the hub was properly seated on the shaft. The vibration was greatly reduced. Might be worth double checking the hub. Good luck, Brian From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Dave via CnC-List Sent: Wednesday, October 26, 2016 9:21 PM To: cnc-list@cnc-list.com Cc: davidjaco...@comcast.net Subject: Re: Stus-List Folding Prop won't open Kevin, I've struggled with the same issue for three seasons. When I first got the boat it have a Martek 2 blade folding prop. When motoring off the mooring no problem. But after sailing the prop vibrated horribly. Throwing it into reverse and then back into forward usually but not always resolved the issue. At the end of the season I sent the prop to Martek to have it rebuilt. I also had the transmission rebuilt and the cone gear replaced. Put the boat back in the water in the spring and found that the problem was still there. The following winter I replaced the Martek prop with a Flexofold. Lwo and behold the problem is still there. I made sure that the engine was in alignment and had two boat yard mechanics out on the boat. When heading into a 3 knot current there was no vibration but when we went perpendicular to the current the vibration resumed. This happened repeatedly. The mechanics told be that the vibration is typical for a two bladed folding prop. One thing that became apparrent during that test was that the maximum rotation I was able to get up to was 2600 RPM. The boat has the original Yanmar 3GM30 and Kanzaki KM3-A transmission. The gear ratio is not stamped on the transmission but, I've been assured that the gear ratio is 2.61:1 and have no reason to believe it's not. I purchased the prop recommended to me by Flexofold which is 2 blade 16x12R. When I told Flexofold about the issue they insisted that the prop was the correct one and I do know that other 35 MK3s have had success with this same set up. The Flexofold blades are geared to one another. So, it's impossible for one blade to open while the other is not. So, that can not be the problem. So, any ideas beyond what I've already done are greatly appreciated. Dave J Saltaire C&C 35MK3 Bristol, RI
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