How can a 19p aluminum = 23p ss.. looking for some advice

My boat is a 1999 Warrior eagle 1891 full V walleye boat.
dry weight without motor is about 2000lb's

Last year i was running a 1996 Johnson 150 (non-fast strike) I ran a 19p aluminum prop and the motor spun 5400 RPM @ 45mph. I tried a 21p SS viper and spun 47mph @ 5300

This year im running a 1997 Evinrude 175 intruder (carbed) I was able to try a new prop and i like it with exception its actually slower then my old 150 setup.
The new prop is a mint condition 23 pitch ballistic currently the 175 with the 23 pitch runs at a top of 43mph @ 5200 RPM's

Man spec is 4500-5500 RPMS.

all three props listed above had excellent hole shots on my boat.

My question is, Why is the 23p SS on a 175 running slower then the 19p ALUM on a 150.

My next question is, I assumed id be able to do low 50 mph's with the 175 Is this a mere dream. i think the boat should run it easily.



Both motors had good compression during testing and ran great.
I tried raising the motor a hole and lost 4mph off the top.

any other ideas?

Re: How can a 19p aluminum = 23p ss.. looking for some advice

Not that uncommon. Not all 19" or 23" props are created equal. On your set up the 23" has a lot of slip which allows for rpm but no speed.

The top rpm you're looking for with that motor is 5800 to 6000.

Re: How can a 19p aluminum = 23p ss.. looking for some advice

Interesting, i thought the orginal man spec is 5500 max?

I found a brand new 21 pitch raptor for 189$ and a 21 pitch viper for 200$


Of the two would you have a recommendation? or should i go down to a 19pitch?



Is there anything i can do to limit slip?

Re: How can a 19p aluminum = 23p ss.. looking for some advice

First, don't expect to see any difference between a 150 6V6 and a 175 6V6 unless you have a light pad bottom boat that's very sensative to small increases in torque. 6000 is a good target for those motors on todays fuel.

I'd play with the set up with the props you have before spending $$ on more. In the end a good performance based 19 may be the way to go. If the set up allows you to get the r's with a 21, then all the better.

Re: How can a 19p aluminum = 23p ss.. looking for some advice

That is very interesting.. Thanks for your help.. im gonna try the 19 pitch alu on the 175 thanks!

Re: How can a 19p aluminum = 23p ss.. looking for some advice

If your going aluminum check out the Turning Point Props.SS performance at aluminum prioces.

Re: How can a 19p aluminum = 23p ss.. looking for some advice

Bud, your problem is pretty simple as Dhadley said, it is absolutely prop slip. In my opinion you need to change to a high performance 4 blade prop to limit your slip to a reasonable amount.When you raised the motor all you did was increase the prop slip more. But when you do this you will find that you can't turn near as much pitch as you are turning now, so buy from a place that lets you exchange the prop for a small fee. Ken at Prop Gods does this and he is a very nice guy. I believe that a 19" 4 blade with a trailing edge cup of about 1" will be perfect for your boat, but ask dhadley about that, I am not as up on the newer props as he is. The cup will help control the water and reduce slip as well. Here are the Prop Slip numbers for both motors and all three props, as you will notice as you went up in pitch the Prop Slip increased as well to eat up most of the gains you should have gotten in speed. With a 4 blade prop and the increased surface area and with the cup you should have a commensurate decrease in Prop Slip and thus an increase in speed.



H

Re: How can a 19p aluminum = 23p ss.. looking for some advice

Being such a common motor, and a good prop topic ill keep this post alive, Thanks for all the great info so far.

i picked up a mint condition OMC raker yesterday off craigslist.org
100$ (how can you beat that, lol's)
if it doesnt work well im probebly gonna sell the ballistic and the raker on ebay.

anyways its a 14.5 x 20 pitch mod # 394753 raker SS

Any predictions on what to expect from this prop?
technically my slip should go down signifcantly... And perhaps be turning around 5500?


I also talked to a buddy that has an extra 4 blade that ill be trying within the next few weeks.