New prop for tubing/skiing?

[JASinIL2006]

I'm considering getting a new prop, partly to have a spare on board, but mostly to get better performance for pulling skiers and tubes with the boat in my signature. I'd like to get better holeshot and get up on plane more quickly.

Current prop is a Merc #832834A45P23, which is I believe is a 14" 23 pitch Black Max aluminum prop.

Moderately loaded, I can hit 50 MPH (GPS measured) on fairly calm lake water at about 4200 RPM.

Drivetrain is a '97 350 Mag Alpha One Gen 2 (260 HP?) on a '97 19' Larson SEI bowrider (not sure of actual weight).

I'm wondering if a 4-bladed aluminum or SS prop (14 x 20 pitch?) would be the ticket? I'm planning to purchase it here on iboats, so specific recommendations would be welcomed!

Thanks,
Jim

 

[jestor68]

Re: New prop for tubing/skiing?

Deleted

On other forums I belong to, if you "delete" a post, it's actually gone.

 

[jestor68]

Re: New prop for tubing/skiing?

What rpm is it turning? The most important instrument in prop selection is the tachometer.
Your prop IS a 14 X 23 if it's a Black Max prop.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

It's in my post... 4200 RPM at WOT (on-dash tachometer) is getting me 50 MPH. I think my engine is rated 4200-4800 RPM at WOT.

Thanks!

Jim

 

[etracer68]

Re: New prop for tubing/skiing?

I would give the 14X20 in Alum a shot. Looks like you have the RPM to gain, and the four blade should be all around better for water sports. Get the spare hub kit also.

 

[airdvr1227]

Re: New prop for tubing/skiing?

A 350MAG in a 19' boat ought to be able to get a house up out of the water. Are you having trouble?

 

[JASinIL2006]

Re: New prop for tubing/skiing?

It does pull, but I was hoping to get a bit more pop on the hole shot. When trying to pull larger skiers (adults), it seems to labor a bit to get up on plane. I thought a 4-blade prop might have a bit more bite.

 

[SkiDad]

Re: New prop for tubing/skiing?

20 pitch sounds like a good idea

 

[Levinz11]

Re: New prop for tubing/skiing?

Does it need a tune up or something? 50 sounds slow for that boat/motor. I have an old 4.3 that hit 45 with a 3 blade 21". I dropped to a 19" 4 blade for tubing and skiing and get 43 now.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

I don't know... it occasionally has what I think are carb-related issues (occas. backfire when dropping the throttle), but most of the time it starts easily and runs very smoothly. I looked at the plugs this winter while the motor was out, and they all looked very clean and were gapped correctly. I've only owned the boat for a year and a half, but the engine is a remanned 350 Mag that was installed right before I bought the boat. Other than the occasional problem during quick acceleration, it doesn't show any signs of being out of tune -- it idles nicely, runs smoothly at all RPMs, doesn't spew excessive amounts of exhaust...

I know the boat isn't waterlogged, because I just replaced the transom, deck and foam this winter. I'm not entirely sure the current prop is optimal -- I'm just at the lower end of RPM for WOT stated in the manual (I just looked it up... RPM should 4200-4600 at WOT). I'm not really interested in going a lot faster than 50 MPH, though, so I've not looked into prop-tweaking to get more MPH at the top end.

I do think I should be able to pop adult skiers out of the water without any trouble; much of what we do is tube and ski, so that's been my primary reason to think about a new prop. Does that make sense?

Jim

 

[callen369]

Re: New prop for tubing/skiing?

I would suggest trying out a 14.5x21 4 blade. The 2 inch drop in pitch will slightly balance the increase in blade area, but your RPM's should still go up a little bit. I'm currently running a Turning Point Stainless 4 blade 14.5x21 that replaced the original 14.5x21 3 blade merc prop, and I'm very happy with it. My RPM's dropped from 4800 to 4500, but still in the range. The added blade plus the slightly larger diameter should give you the hole shot you are looking for. Plus the Turning point is also ventilated to help hole shot as well.

I have the Turning Point Hustler Aluminum as well, in a 14.5x21 4 blade, that I now keep as a spare. Also very happy with it, though it really brings the bow up on takeoff, and likes to be trimmed up quite a bit.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

After doing some thinking and some more reading, I'm starting to wonder whether my on-dash tachometer is accurate. I've got a Tiny-Tach and I'll use it to check the on-dash reading I'm getting.

 

[mpsyamaha]

Re: New prop for tubing/skiing?

Confirming rpms would be good, and then go from there. If the rpm reading is true then going down in pitch will certainly help.

 

[Bamaman1]

Re: New prop for tubing/skiing?

Have you considered putting a $400 set of hydraulic trim tabs on your boat--instead of changing the prop?
It gets the nose down immediately and makes your boat tow like it's got 50 more horsepower.
Your boat will ride like it's 5' longer, and you can quickly tuck the nose down when you come up on a big wave.
Get too many people sitting on one side, and you can level the boat laterally.

I put them on my inboard outboard open bow V hull, and it was the best money I ever spent. Every full hulled inboard outboard boat, especially with a heavy V-8 motor, needs to come with them standard.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

I have a set of Smart Tabs, and they do help somewhat (but more on the high end by reducing porpoising and chine walking). I'm not sure about adding hydraulic tabs... seems like a lot of fiddling to me. I'm new enough to driving a boat that I sort of appreciate the low-maintenance approach of the Smart Tabs, even if I might be giving up some ability to tweak.

I'll see what I find out when I run with the Tiny Tach and I guess that will help make a more educated decision.

Thanks!

 

[JASinIL2006]

Re: New prop for tubing/skiing?

I ordered a Michigan Wheel Vortex prop, 4-bladed with 20" pitch. Looking forward to giving it a try!

 

[Slip Away]

Re: New prop for tubing/skiing?

I ordered a Michigan Wheel Vortex prop, 4-bladed with 20" pitch. Looking forward to giving it a try!

That is the prop you will like best. Part # 992204 I believe.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

That's the one! I can't wait to try it. I even popped for prop wrench so I can keep it and the current prop on the boat.

 

[Mule Laker]

Re: New prop for tubing/skiing?

Does it need a tune up or something? 50 sounds slow for that boat/motor. I have an old 4.3 that hit 45

I doubt it. Big difference between going 45 and going 50 in a boat.

 

[JASinIL2006]

Re: New prop for tubing/skiing?

Before I ordered, I verified my onboard tach with a TinyTach; the onboard tach was spot-on.