Crestliner 1850 Sportfish Prop Question?

Crestliner 1850 Sportfish a with Johnson 140 4-stroke. I troll and water ski with it

This boat came with a 23-pitch 13.25” diameter aluminum prop. The top speed is 39 mph GPS with 5400 rpm.

I tried a second prop and this time it was a 21-pitch aluminum, same diameter and the top speed was 40 mph but the motor did hit 6000 rpm. Hole shot was still ok.

The dealer said we should get 43-45 mph with this set-up with two people in the boat but I have not seen it yet.

The motor was broken in completely and correctly.

The motor is set at the second hole from the top.

Can anyone provide suggestions on this boat to help me find that top speed?

Thanks

Bobber,
I think the Johnson can handle a 14″ diameter prop. You might try a Solas S.S. 13 3/4 x 20 pitch. Mark’s prop shop in Forest Lake can help you out. I run the Suzuki 140 on a 1850 Fish Hawk with a Solas 13 3/4 x 20. I get a good hole shot and run 43-44 gps.

Sandbar

What about trim? With a stainless prop of the same diameter and pitch you can trim it out further…because of the cup on it, trimming way out on my last boat was good for about an extra 5 mph.

Hello, I am new to the site and think there is a lot of excellent things on here. Anyway, I also have a 1850 Sportfish with a 140 4-stroke Johnson and had a Hustler Prop system on it. I have never seen this before or done it, but I broke all 3 blades off of my prop last week and hardly even hit whatever was under the water. I was told it wasn’t a composite prop, but it sure looked like one. Anyway I ordered another prop, because Hustler has the exchange system and am going to try the 13 1/4 x 21. And I think that was what was on it before and my speedometer said I was going 43 with that.

Both of the stock aluminum props I used also look like they have a slight cup. The blades also look wider than my friends Yamaha 150 4-stroke prop.

Doesn’t cup lift the hull? I think it also robs top end speed.

The cupping will lift your bow more, but from what I’ve ever read, it should actually increase your top end, not rob from it. Bow lift=less hull in the water=less resistance=more speed. (in most cases)

Good Luck!

What I am wondering if the cup in the prop is needed. I would think if not, then a non-cupped prop would move the boat faster because of less drag?

That’s a good question Al. I don’t know how it would affect drag. Maybe someone else can chime in here??
I would think that less cupping would cause the prop to cavitate or blow out easier.

Sandbar, Does Marks have a website?

So what you guy’s are saying is I could go to a 14 3/4 in. prop? I have a johnson 140 4 stroke and it came with a 14 1/4″ prop. I’m running it on a crestliner fish Hawk and getting 40 gps speed. Will that 1/2″ make a difference? the pitch is at 21.

Chappy,
Sent you a pm with Mark’s phone number. Not sure about the 1/2″ change in diameter question, but I would think your rpm’s at WOT would increase by 200-300 rpm’s. I am running 6000-6100 rpm’s with a full load before “blow out” at WOT.

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