Prop Recomendations

[wyoben]

I have a heavy, I mean heavy 21ft deep I mean Deep hulled boat. Need a prop for a 200 hp Black Max (1983). I tried it for the first time with a 14x17 big flat blade prop today. The best I could do was 4200 RPM with the motor trimed so the prop was almost out of the water. No where near planning. If I didn't trim it up that far it would bog down and die. I am also fighting a fuel pump problem, and am waiting on a rebuild kit. What props are avialable for this Motor, don't want to pull a skier or go really fast, If I could just get it to plan and go 25mph I would be happy.<br /><br />Thanks<br />Ben

 

[Spidybot]

Re: Prop Recomendations

Oh dear.<br /><br />Please state more specific data. Boat make & model, ready-to-go weight, achieved rpm at wot with reasonable trim, speed at wot, hull state, prop state, motor overall behaviour (messy fuel pump has a LOT to do with performance!), motor mount hight on transom.<br /><br />200 hp on a 21' should do much better than 25 mph unless you're carrying tonnes around on the water.<br /><br />There are plenty - and I mean PLENTY - of props available for your motor.

 

[Chris1956]

Re: Prop Recomendations

Wyoben, I agree with UU. How were you able to get that motor to spin 4200 RPM and not be on plane? It sounds like you were slipping the prop. A 200 HP should plane that boat easily. I suspect you have motor issues. A 17" pitch prop on the boat should be close to optimum.

 

[MercMark]

Re: Prop Recomendations

I'm certainly not an expert, but I'd be hesitant to take a two stoke out and crank the RPMs up with a fuel pump problem. Fuel = lubrication. But then again I'm a little paranoid since I blew a cylinder.

 

[wyoben]

Re: Prop Recomendations

Here are pics of my boat, I spent all winter fixing it up, its a 1979 IMP, it used to be an inboard with a Mercruiser 470 and a pre alfa outdrive, as you can see I've done a major conversion adding a center console etc. The boat has a hand laid hull, which is why I thought it would be worth fixing up, even when it was completely gutted (no floor) just the hull, one man could not lift one end! As you can see I've added a lot of wood and about 15 gal of Epoxy resin and glass, it does float however with the water line about 5 inchs below the top of the splash well line. The first time on the water was yesterday, the motor worked ok below 2000 rpm except running out of full after a few minutes, which from what I read sounds like a fuel pump problem, although I inspected it and it looked ok, but from reading the posts hear, just cause they look ok does not mean they are good. So I got a diaphram & check valve kit on the way. Here are the pics _<br /><br />

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<br /><br /><br />This prop came off the old 470/pre alfa set up, I had it repaired and repitched, its was 14x19 it is now 14x17, from looking at other outboards at the lake it seem most do not have the mass of the blades like this one does. Anyway I'm in a bit of a pickle here. I have rented cabins this coming weekend at Fort Peck in Montana, the walleye fishig is hot right now and I have 5 days to get it going. Its an 8 hour drive from here one way. There is no parts and service there so I need to be ready, this is a huge lake with more shore line then the coast of California so going 20 mile to the fish is not uncommen. Need my big motor to run! I have 5 days to geter done! Please HELP!

 

[wyoben]

Re: Prop Recomendations

Is this prop affecting the performance?

 

[quantumleap]

Re: Prop Recomendations

Your motor should plane that boat wrong prop or not. That pitch should be in the ballpark. Try another to make sure the hub isn't bad. If not, then there may be a problem with the motor. I would try a prop made for your specific motor in 15-17p.

 

[wyoben]

Re: Prop Recomendations

Correction, the prop I was using is a 15x17 not a 14x17

 

[achris]

Re: Prop Recomendations

Ben,<br /><br />That looks like a fantastic ocean boat. The 17" prop should be pretty close, but as some of the other posters have said, get the engine right, particularly the fuel system. You could easily do some serious damage.<br /><br />Chris............

 

[Spidybot]

Re: Prop Recomendations

Congrats on the work - looks sharp!<br /><br />If you're concerned about weight, as we all are most of the time, remove as much as possible. 3 (!) outboards seems like overkill!<br /><br />As mentioned before, your motor needs to be running properly first. Then a prop discussion to get the optimal type & size for your needs (which btw. may not be the one you have).<br /><br />Boats this size cruise around with engines from some 125hp and although not impressive, it is a sign that your 200 should make it do pretty well.<br /><br />If your fuel pump is weak, try squeezing the bulb when at wot to aid the fuel supply.