What prop to run

[dbrown]

Hey gang,
Great forum!! Gotta a question 'bout what prop to run on my
rig. I'd like to swing as tall a prop as the engine will stand. Hole performance is not an issue due to having a spare 19 when I want to do some skiing ,etc. What I am looking for is the best top end. Setup is a follows:

1981 Carlson C-500
115 Johrude (stock)
21 x 12/34 Michigan aluminum

Thanks in advance!
:D

[Liqui-Fly]

What is the height of your propshaft in relation to the bottom of the boat? If you are 2 inches or more below I think a 22 Raker might be your best. If you're abover that an over the hub style like an SRX will probably be better. What are your current RPM's with the prop you have?

David

[dbrown]

The cavitation plate is approximately 3/4 " above the bottom of the boat. I'm sure my tach is incorrect, but it was reading approx 5700 rpm at 49.7 MPH GPS. I am also possibly looking to go to a johnrude 140. That being the case, how tall a prop would the 140 swing?

[Liqui-Fly]

If you don't care about skiing ect...then you need to raise that motor so the propshaft is around 2 " below the pad. A setback plate will help your hull also. This will allow you to spin some more RPM's and run a bigger pitch prop. If you're interested in just throwing a prop on for now and goinfg faster with your current set up find a 20 or 22 Raker. I think the 20 would be better to bring up your RPM's...Rakers are actually higher pitched than advertised....and run it. You won't be disappointed. Get your tach right too....it seems a little high but not much. Do you know the gear ratio in your lower unit?

David

[BarryStrawn]

My first boat was a new '79 Carlson CVX 16 with a Evinrude 115. I think these are the same hull as your C500. With the engine in the bottom holes, 23" over hub, low fuel and one person it would run 60 pretty easy. This was 23 years ago and the 23" prop was the old silver epoxy painted ones that evolved into the SRX. A jackplate and some setback would likely have helped a bunch but I didn't care to replace the splashwell mount steering. Dealer friend also had a CVX16 he played with using a 140. It had a good 5mph on mine with the same prop.

I also used 19" and a 21" SST props to pull water skiers. The 21" was marginal for a large guy unless they were good on one foot slalom starts. The 19" could pull anyone up.

I have heard good things about the Raker but never run one myself. The overhub props like a SRX or small ear Merc chopper (rehubbed) will also work at the low transom height, just not as efficiently as if they were jacked up. Try to borrow some props if you can.

[dbrown]

As far as I know it is stock. I ran some numbers on the prop/rpm/slip etc, and the came out close to 1:2/2:1 cant ever keep that straight

araaaaaaarrrrrrrghhhh

OK 1 turn of prop to 2 turns of motor

my head hurts........
thanks

[Michael Martin]

I think its closer to a 1.87

I have a 20 and a 22 raker hubbed for a V-4 OMC both 6/10 on the S&F scale

Dan Agnew has a 24 Raker also hubbed for a V-4.
If your wanting to really stroke your motor give Dan a call he'd be happy to discuss the possibilites.... 803-364-9351


Mike Martin

[BarryStrawn]

The V4 gear ratio should be 2:1. 13 teeth on the drive shaft gear and 26 on the prop shaft gear.

[Michael Martin]

brain fart I was thinking v-6.

Barry thanks for the correction.

[chris_lacey]

What do you want for the 22 Raker? I had a wanted post on the buy and sell area, but only 20's and 24's were offered. Let me know, definately interested. A 6/10 is fine as I have a Johnson 120 on my V-King while I repair my Merc and don't want a fortune tied up in a temp setup. Thanks,

[chris_lacey]

Back to the top. How much for the 22 Raker?
Thanks,

[Rickracer]

I had the identical boat! Same year, same colors, nearly the same choice of power. I would say the 22 Raker would be the best choice, until you go for the 140, then you'll want the 24. Best things I did to that hull were a 5.5" jackplate, Dual RideGuide, and a hull blueprint. I really wish I had added a pad too though. I was turning a 24 Raker 6800~7000 with a light fuel load, empty boat, (no skis, kneeboards, extra jackets or extra anchors) and runnin solo. It will chine walk at 65 or so. That's what the pad would have cured, I'm fairly certain. I traded it for an '86 21' Daytona hull and trailer. :cool:

[Michael Martin]

I'm not ignoring ya just tring to find the prop.
I'll take 275.00 + shipping. Send me an e-mail

[email protected]

[chris_lacey]

Michael, check your email,

[dbrown]

hey Rick, thanks for the info on the chine walking. The target speed I had in mind when I started was around 65. I have located a johnrude 110 vro thats gonna have a fresh
overhaul. What I have been told is its is equivalent to athe 80/81 140's in power. I don't intend to use the vro, I'll mix my own, that way I KNOW whats in the mix. again, thanks for all the
help

DB

[Michael Martin]

Why not just build the motor you have to a true BIG DaWG.

There are endless possibilities on what ya can do with the existing motor you have. Big bore carbs, shaved heads, a little grinding on the intake, fingerport the block and pistons, Lighten the rods and pistons.....

You could add an additional 40-60HP that would really scream. Even if you only did the carbs and heads you would see a noticeable differance. Those motors really wake up when you throw them a little more compression. Talk to "Laker" or Dan Agnew or any of the other v-4 guru's on the board.
I'm sure you could find a set of heads on here & have them cut. That way you still have the stock heads as spares.

It really just depends on what you want.

Speed cost money how fast do you want to go?

(thats also the reason I'm one of the slowest on the board too!!:D :D :D )

Mike