Need a good prop guy to help.

[PINIT]

1989 19' Celebrity bow rider. 5.0 merc, alpha one. boat weighs 3000 pounds off trailer. It has a 13.25 17 pitch prop on it now and im only reaching 4000 rpms at WOT. top speed about 43 mph. my problem is it takes too long to plain out. Ive went through all the steps up till now. ive checked for water logged boat and Engine issues. All i can say is the thing runs great. revs up fine, idels smooth. I had a 19 pitch 4 blade that i tried and it may have helped hole shot but killed my rpm even more. I know everyone says a 15 pitch is too low for a boat like this but im lost and need help with which way too go next. Thanks guys. If you get a chance check out my resto build in my Sig.

 

[PINIT]

Re: Need a good prop guy to help.

Anyone? I really hate to throw money at props. Thanks.

 

[hwsiii]

Re: Need a good prop guy to help.

Pinit, I need to know the exact gear ratio for your outdrive.

H

 

[jestor68]

Re: Need a good prop guy to help.

I run a 4.3(220hp)Mercruiser on a 3500lb(dry wt) boat, and it turns 4800 rpm with a 15.5 X 17 Solas 3 blade aluminum prop. (Not the boat in the picture. That's my other boat)

Something sounds not right about your prop diameter, since alpha(and bravo) drives are designed to swing 14+inch diameter props. In the 17" range, the "standard" size would be something like 14.5 X 17. The 13 inch diameter props are meant for the smaller gear case outboard motors(under 150 hp).

The typical size alpha prop in the 15" pitch range would be 15X15, or 15.5X15.

The larger diameter props are designed for heavier boats. They generate significantly more static thrust.

Prop diameters over 14.5" require a different trim tab, unless your unit has power steering, in which case you wouldn't have the trim tab. Alpha(and Bravo) drives can handle prop diameters up to 16 inches with the absence of the trim tab.

The first prop I would try on your boat would be the Solas 15X15 aluminum(costs less than the Mercury prop). The 2" drop in pitch is offset somewhat by the increase in diameter. It will generate more static thrust and get your boat out of the hole and up on plane faster. And it costs under $100!

 

[PINIT]

Re: Need a good prop guy to help.

Looked everywhere for numbers or anything i could identfiy the ratio from and couldnt find any.

 

[PINIT]

Re: Need a good prop guy to help.

I run a 4.3(220hp)Mercruiser on a 3500lb(dry wt) boat, and it turns 4800 rpm with a 15.5 X 17 Solas 3 blade aluminum prop. (Not the boat in the picture. That's my other boat)

Something sounds not right about your prop diameter, since alpha(and bravo) drives are designed to swing 14+inch diameter props. In the 17" range, the "standard" size would be something like 14.5 X 17. The 13 inch diameter props are meant for the smaller gear case outboard motors(under 150 hp).

The typical size alpha prop in the 15" pitch range would be 15X15, or 15.5X15.

The larger diameter props are designed for heavier boats. They generate significantly more static thrust.

Prop diameters over 14.5" require a different trim tab, unless your unit has power steering, in which case you wouldn't have the trim tab. Alpha(and Bravo) drives can handle prop diameters up to 16 inches with the absence of the trim tab.

The first prop I would try on your boat would be the Solas 15X15 aluminum(costs less than the Mercury prop). The 2" drop in pitch is offset somewhat by the increase in diameter. It will generate more static thrust and get your boat out of the hole and up on plane faster. And it costs under $100!

Thanks for that info! everything helps!

 

[steelespike]

Re: Need a good prop guy to help.

Pinit, I need to know the exact gear ratio for your outdrive.



H

Hi H, welcome back.My info indicates a 200 hp is 1.70 and a 230 is 1.50.
Not sure how accurate that info is.
Seems like 5.0 could twist up a 17"prop pretty good.
Also wot speed maybe around 50 with the right prop.

 

[bnicov]

Re: Need a good prop guy to help.

I think you may have an outdrive with the wrong gear ratio. You need to find either the ratio OR at least the serial number of the drive.

 

[PINIT]

Re: Need a good prop guy to help.

I think you may have an outdrive with the wrong gear ratio. You need to find either the ratio OR at least the serial number of the drive.

That has crossed my mind. When i bought the boat the outdrive was freshly painted shiny black. now that some of that has wore off i can see quite a bit of corrosion around the bottom, Guessing this outdrive came from salt water or something. the anode or trim tab, is ate up pretty good also. and my boat has power steering and stated by Jestor ^ power steering models didnt have trim tabs?? So if its the wrong gear ratio it could have come from a 5.7 or 7.4 model engine?

 

[PINIT]

Re: Need a good prop guy to help.

Called the PO and he said it was changed but he didn't know what too, Ill look for a serial number again. but i didn't see any numbers when i looked before.

 

[spdracr39]

Re: Need a good prop guy to help.

My 08 5.0 came with a 1.47 drive and i have to run a 17p to hit 4500 rpm. I am probably going to get a 15p also. If they replaced the drive with one off of a 350 mag or larger it is probly a 1.47. DonS left us this in another post. the formatting is off but i don't know how to attach an excel document.

Mercruiser Sterndrive Gear Ratio Chart

Use this chart to determine your gear ratio before ordering a Mercruiser R-Style, Alpha 1 or Alpha 1 Gen 2 sterndrive.

Mercruiser R-Style Sterndrives (1969 - 1983)
Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
2.5 Liter 120 2.5/153 4 1.98 20-24 1969-1983
2.5 Liter 130 2.5/153 4 1.98 20-24 1969-1983
165 165 3.7/224 6 1.65 24-24 1969-1983
470 170 - 190 4.3/262 4 1.84 17-19 1969-1983
215 - 233 205 - 230 351 8 1.5 20-22 1969-1983
260 260 5.7/350 8 1.5 20-22 1969-1983

Mercruiser Alpha 1 (1984 - 1990 Models)
Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
2.5 Liter 120 2.5/153 4 1.98 20-24 1984-1990
3 Liter 130 3.0/181 4 1.98 20-24 1984-1990
165 165 3.7/224 4 1.84 17-19 1984-1990
175 175 4.3/262 6 1.84 17-19 1984-1990
180, 190, 470 180 3.7/224 4 1.84 17-19 1984-1990
200 200 5.0/305 8 1.65 24-24 1984-1990
205 205 4.3/262 6 1.84 17-19 1984-1990
230 230 5.0/305 8 1.5 20-22 1984-1990
260 260 5.7/350 8 1.5 20-22 1984-1990
350 Magnum 270 5.7/350 8 1.5 20-22 1984-1990

Mercruiser Alpha 1 Gen 2 (1991 & Newer)
Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
3 Liter 130 3.0/181 4 2 24-24 1998-2005
3 Liter 130 3.0/181 4 1.94 20-24 1991-2005
4.3 Liter 175 4.3/262 6 1.81 17-19 1991-2005
5.0 Liter 230 5.0/305 8 1.61 24-24 1991-2005
5.7 Liter 260 5.7/350 8 1.47 20-22 1991-2005

 

[PINIT]

Re: Need a good prop guy to help.

Thanks, Just left a prop shop, guy says my prop was a 19, someone took the cupping out and re stamped it 17p. trading it and some cash for a true 17p SS from him. ill give it a try Thursday.

 

[PINIT]

Re: Need a good prop guy to help.

17 wasn't what i was looking for, i got a 15x15 and its great. does everything i want it too even with a load. great prop for a loaded boat and pulling. Solas rubex bought right here from iboats.

 

[90stingray]

Re: Need a good prop guy to help.

Just to help finish up your thread for others that may be researching this some day... what kind of numbers are you getting with your 15p?

 

[PINIT]

Re: Need a good prop guy to help.

Just to help finish up your thread for others that may be researching this some day... what kind of numbers are you getting with your 15p?

15x15 was 4300 rpm at 40 mph GPS. and this was loaded, Full tank of gas, 5 adults, ice chest, gear. 5.0 Merc. alpha one with 1.50 gear ratio.