Search found 19 matches

by JhlFin
Fri Apr 03, 2020 8:58 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

It has 1:1 Gear ratio, direct drive. Marine engine based on this is rated at 5500rpm max, i have rev limiter at 6500(not stock engine). I think max cruise rpm will be 4000 and will run short periods of time at 6000rpm. Im not worried about running high rpm, these are sturdy little engines and it won...
by JhlFin
Thu Apr 02, 2020 9:29 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

Sorry, my english is not that good :oops: So propeller diameter will be cut from 11" to 10". Pitch will remain 15" and cup is added. If it is needed, i will try more pitch. Prop guy said that with high rpm bigger propeller will start to cavitate from high tip speed. Smaller prop should have cleaner ...
by JhlFin
Wed Apr 01, 2020 10:31 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

Little update, i found propshop that was willing to modify my propeller. We talked a bit and we decided to cut prop to 10" as blade tip speed gets too high and causes cavitation, also prop will be cupped. They will also measure rake of propeller and change it to 5 degrees aft rake if it is less. May...
by JhlFin
Wed Apr 01, 2020 10:24 am
Forum: Boat Power
Topic: CVT scooter motor as inboard?
Replies: 7
Views: 602

Re: CVT scooter motor as inboard?

It might not be that bad idea, probably needs lot of testing and tuning. I'm no expert at cvt:s but in know those can be modded to work on diffrent applications with weights and springs. You could also use chain drive from cvt to propshaft and do gearing there as needed. If you have tools and materi...
by JhlFin
Wed Nov 27, 2019 9:12 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

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 stee...
by JhlFin
Fri Nov 22, 2019 8:11 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

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 ...
by JhlFin
Mon Nov 18, 2019 9:48 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

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 ...
by JhlFin
Sun Oct 13, 2019 11:30 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

I cant drive wide open with either prop, engine will over rev(no limiter) With 11x15 6000rpm speed was 35mph. 10x12 at 6000rpm speed was 28mph. With smaller prop it went worse at every rpm, felt it right away. I know that clutch may slip, but i if thats the case, i think with smaller prop it should ...
by JhlFin
Sun Oct 13, 2019 7:34 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

Tried other prop repitched, so now 10x12. Quite funny really, at 6000rpm prop slip was again 59% :lol:

So yeah, i guess that strut is just that bad. I ordered new rubber bearing, smallest i could find. Little bit machining and welding and ill guess try again :D
by JhlFin
Wed Oct 02, 2019 10:15 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

Im sourcing materials for new strut, have not found yet. Well i could make it from steel, i have materials for that, i guess rust wont be an issue with good paint and boat always on trailer. Water around me is brackish i think. I live in an island, in smallest town in Finland :D Just machined taper ...
by JhlFin
Fri Sep 27, 2019 10:47 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

I have 10x10 prop with wrong taper. I guess ill try that after some machining. And Thanks for replies! It helps a lot, helps to think :D
by JhlFin
Fri Sep 27, 2019 9:21 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

900 pounds running weight sounds about right. I'll try to get bit weight off. Engine is marinized car engine, they say 90hp in car use. Same base engine in volvo penta application is aq125 117hp, they have slightly diffrent camshaft and manifolds ofcourse. Horsepower wont be issue, im planning on ge...
by JhlFin
Fri Sep 27, 2019 4:59 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Re: Tiny might propeller slip

Just dont look photos too closely, its ugly and not finished. Ill try to remember to take new and better photos. That adjustable strut is going to bin, going to make new in winter. I have clutch and bellhousing from car, i found it easiest way. Covers flywheel and nice surface to mount bearing. I ha...
by JhlFin
Thu Sep 26, 2019 5:08 am
Forum: Boat Power
Topic: Tiny might propeller slip
Replies: 28
Views: 7332

Tiny might propeller slip

Hi, i have test drived my tiny might few times now, in im wondering why i got so much propeller slip. I have 2100cc volvo engine with straight drive, put out about 120hp. Engine weigth about 360lbs. Shaft angle is 15 degrees. Propeller is Mikado 11*15 bronze. At 6000rpm i got around 35mph, it sound ...
by JhlFin
Tue Sep 10, 2019 9:57 am
Forum: Power Boats
Topic: Tiny might propeller to rudder distance
Replies: 4
Views: 3840

Re: Tiny might propeller to rudder distance

Hi, now i have test drived the boat, lot of little problems still, engine not running properly etc. I managed to get 5-6000rpms shorty on test drive, did not have speedo, but with questimated speed prop slip was about 50% 😲 I know few issues that could cause problems. Prop strut is adjustable type (...

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