Finally done!
Stock ( for now ) Harbor Freight 212cc engine
Direct drive 6ft shaft
7" SPS aluminum prop ( Dont hate unless you wanna buy me a stainless one!)
11 mph top speed by myself on a 14x36 Duracraft
10 mph loaded with 2 180lb guys and a spare 4 stroke engine
I may try a larger SPS prop, their cheap enough to experiment with!
Any mathmaticians on here that can determine if a bigger prop will help top end?

Appreciate all the info on here about homemade builds cause everybody don't have the spare $$$$$$
to drop on a store bought unit.

How did you get a 7inch sps prop to fit a 3/4 threaded shaft?

I had a machine shop make an adapter.

I run a 7x5 prop with that engine if it is a straight drive with out a reduction to the drive shaft.

Mark F. Cheney

You will have a SS prop soon. You didn't hit any fish,turtles,frogs or leaves on your test run. I know from experience.Think your prop is oversized now. Need to know rpms

That's really neat so I take it screws on the shaft ?
What's the other end look like I might have one built for mine so I can keep a back up prop in the boat.

I guess I need to pick up a tachometer. Think 7" may be too large for 7hp?
It don't bog down at all. I find it kind of odd that it runs dang near the same speed
Loaded down or empty. I would love to see a few more mph out of it eventually.

Joel, the 3/4 shaft is smooth at both ends and through bolted with 1/4" grade 8 bolts and lock nuts. The pic of the adapter is before the hole was drilled.

I would throw a 6 on there to see what happens. Like you said they are cheap so why not. The tach will tell all

I will try a 6" and see how it goes. I may be expecting too much for a 212cc pushing a 1436 Duracrft!
What size boats are you pushing with a 6" prop? What's kind of speeds are you getting?

I had a 7" on a 13hp pushing a 1542 around 15mph with 2 guys,dog and decoys

6" prop just came in! I hope to try it out this weekend and will post an update on speed rather
It be slower or faster. If nothing else, I got a spare now.

I think you will find the 6 inch prop to small. Should have ordered the 6.5 inch.

Natty light tall boyz. Woooooooooooooooooooo. Got my 2nd DUI thanks to those back in he day

Looks good. What did you use for bushings and seals?

Thanks. Seals and brass bushings from McMaster. Doesn't leak oil and shaft spins freely. I was going to change to bearings if the bushings didn't work but they work fine.

My boat weighs 100 pounds. So that's probably a big factor.

Update....adjusted the throttle stop on the engine until right before the governor
Kicks in and added a Cheap straight through exhaust. Loud at high RPM .Same 1436 boat with same 7 inch prop with about 200 extra pound in the Boat including my 5 year old son in the front........same GPS.......15 mph...getting better......

Have ran it my yourself since the changes?

That is today's speeds, 15 mph
Pissed all the Bass Fisherman off!
Sounds like a single cylinder Harley!

Mudslinger- Have ran it my yourself since the changes?

Ahhhh...by myself? No. I will have to try it when I don't have my son with me. Might see 16?

Oh, and nice build ghetto, I would love to try mine on a lighter/narrower boat and see what it does. I hope to evenually hit 20 mph