Tiny might propeller slip

About inboard or outboard motors.

Moderator: Bill Edmundson

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kens
Posts: 4729
Joined: Wed Nov 12, 2003 5:25 pm
Location: Coastal Georgia

Re: Tiny might propeller slip

Post by kens » Sun Oct 13, 2019 11:40 am

Whoaaa, NO, no.
You size the prop such that WOT rpm is held in check by prop size.
you have a too small a prop right now.
you need bigger prop not smaller;
if the engine is rated at 6000rpm, then you size the prop such that you do not exceed 6000 because of the size of the prop.

Bill, the clutch should be of enough ability to hold all the engine power.

A prior post said you had a 11x15 prop and 6000rpm. if at that point you were not WOT for fear of over-revving, then that is too small a prop right there.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

JhlFin
Posts: 15
Joined: Tue Sep 11, 2012 12:43 pm

Re: Tiny might propeller slip

Post by JhlFin » Mon Nov 18, 2019 9:48 am

Finally got new strut made, took long enough.

Had litte problems when welded strut, warpped strut housing. First bearing was destryed while installing. Little bit of work and i tought that now it would be good, but not... Second bearin installed, well guess what? too tight :D Well i sanded it a bit and now its ok for testing, just hoping that weather gets bit better.

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User avatar
kens
Posts: 4729
Joined: Wed Nov 12, 2003 5:25 pm
Location: Coastal Georgia

Re: Tiny might propeller slip

Post by kens » Mon Nov 18, 2019 7:52 pm

Very nice fabrication work.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

JhlFin
Posts: 15
Joined: Tue Sep 11, 2012 12:43 pm

Re: Tiny might propeller slip

Post by JhlFin » Fri Nov 22, 2019 8:11 am

Last testdrive for this season with new strut. New tachometer acted pretty much same as old, need to check wiring. Dont have accurate reading, but max speed was pretty much the same. So strut was not the issue. I feel like front of boat is too heavy or trim tabs were at wrong position. Lots of work to be done in winter, more testing in spring :)

https://youtu.be/cB0GuI2oyY0

JhlFin
Posts: 15
Joined: Tue Sep 11, 2012 12:43 pm

Re: Tiny might propeller slip

Post by JhlFin » Wed Nov 27, 2019 9:12 am

Im thinking that my prop is not made for high speed/rpm, blades are thick and not even finished properly from what i can tell. i cant find any other suitable props in Finland. I would be very happy if someone could guide me to find and choose right steel prop. I think someone used 10x15 2 blade steel prop with honda 4cyl engine and it was fast, i have heavier engine, but horsepower i can match :) Would 2 blade propeller be better option, or atleast steel 3 blade?

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