Does anyone have experience with the autoprop "clunking". I was another boat with an autoprop which had a significant "clunk" , more than I would have expected.
It appears to do so when engaging forward, but not reverse, but once engaged there is no vibration at all at any speed. It this just a normal part of the operation, given that it is quite heavy, or is there a possible problem?
Any feedback would be appreciated.
Thanks
Derek
Derek,
I think that the clunking when shifting from neutral into either gear is normal. Each of the three blades of the autoprop revolves around a double set of ball-bearings. When you assemble the prop after routine maintenance (cleaning), you are supposed to tighten the nut holding the blade to the hub just tight enough to allow free spinning, but not enough for sloppiness. It is a very fine adjustment. If you tighten the nut enough to get rid of the clunking sound, the blades will not rotate properly. The prop is quite heavy, and each of the blades have quite a bit of mass. I think I've done a pretty good job of adjusting the nuts each year, and I still have a clunking sound. Obviously the engine should be at minimum idle speed when changing gears. Hope this helps.
I got rid of mine because of the clunk and the way it eats up the Cutlass bearing. Went with a flex-o-fold and I have been as happy as a clam for 4 or 5 seasons. However in fairness most people love the autoprop. Flex o fold is great for motoring, sailing or in reverse and it was priced (or was) much better.
Thanks for the feedback.
I suspect that the previous routine maintenance may not have adjusted the nut properly so that the balde are maybe slightly too sloppy.I will check this out at the next haul and also beaother alternatives in mind if I can't live with the autoprop.
Derek,
Check out the Kiwi prop as an option for a 3-blade feathering.
I put one on last season and really like it.
It's the same weight as the standard Michigan 3-blade bronze prop.
Steve
http://www.kiwiprop.com/
I've had the Flex-o-fold on for two years and love it. It's great if you have to contend with kelp. A friend has the feathering Kiwi prop and he has no problems with it. Both of them back well.
A question for the happy flex-o-fold owners: What is your engine idle speed? I ask this because I just bought a flex-o-fold prop, and as I took it out if the box, I realized it is WAY heavier than my old 2 blade Sailor prop. I have not yet installed it. Last year I raised my idle to about 900 to prevent a shake and occasional cutoff when shifting (this issue began after replacing my motor mounts w/ Vetus K75s. There appears to be a resonance with these mounts when the motor is throttled back quickly. No longer an issue with the higher idle.) Anyway, I wonder if this heavy prop and higher idle speed will give me trouble, such as big clunks when engaging, transmission wear, etc.
When first going into gear my engine idle speed needs to be about 1000 RPM any slower and it is rough. a little clunk when first going into forward but not a problem. I attributed some of that to my getting a 10 pitch instead of 9. I do not get full engine rpm as the engine speed of about 24-2500 will push us along at 7-7.5 knots depending on the water conditions.
I've run a tach on my engine to calibrate my tach reading and I have a 1.25 factor for correction. (1900 on the tach is 2375engine speed) That is my max. without smoking.
Reverse is smooth at idle setting and when docking the idle speed keeps me going too fast, I just take it in and out of gear. to maintain about 2 - 2.5 knots.
Our marina is a little "hot" so my special prop zincs only last about 4 months. They are a little pricey as I haven't found a local source ..... yet. Any suggestions for an alternate source would be well received.
I found an alternate supplier for Auto-Prop cone zincs at downwindmarine.com. Just type autoprop in the search window. They have H5 zincs at $27.90. Don't know if this a good deal since I am on my first zinc, only 15 years old in fresh water. Located the source after replacing my shaft last year and was concerned about using the original zinc.
Jack F Stewart
1993 C36 #1233 "Windancer"
Port Clinton, OH
I always thought that engine idle was when you were NOT in gear so that it should not be altered by the prop. All these folding props have heavy hubs, unlike the kiwi, that eat up the Cutlass bearing so make sure you have a tool and know how to use it. My bearing did does not have a set screw holding it in place making the pressing operation all the more fun. But with a good tool and the proper rachet, its not so bad.