Prop for Lund Explorer 1800 SS

Lund Explorer 1800 SS – 140hp Suzuki

I put on a new prop — last night was the first time opening her up. (The last prop I had busted and the blade with the size/pitch stamp sheared off, so we were left guessing a little bit as to proper prop size…)

I put a 19″ pitch on, but when I got it out on the water, I was maxing out RPM’s at 6500. Upper end speed was good and hole shot was great, but the high RPM’s worried me. (I assume my limiter was keeping me from going higher). With my last prop, 6200 was generally max RPM at WOT.

The guy at the shop suggested step up to a 21″ to give a shot.

Sound about right??

Thanks!

I have been talking to guys at different shops about props lately and just went from an aluminum 17p to a stainless 15p and I went up about 500 rpm’s. The guy at the prop shop in Hudson told me you will most likely see a 200 rpm difference by changing 1 number(inch) in pitch. Go up in pitch lose rpm’s go down in pitch gain rpm’s.

The prop you mention sounds just about right

That’s about what I was thinking.. Thanks for the help!

Update… Tried out the 21″ pitch prop… Was only getting 5600 to MAYBE 5800 RPMs if lucky when trimmed exactly right. Top end speed wasn’t quite what I would have expected with a lightly loaded boat (~42mph), but it was close. The engine didn’t seem to want to trim up very far before leaving the “sweet spot” and jumping RPMs. I was usually getting 6200 RPM’s consitantly with my last prop and topping out at 45 mph+ in a lightly loaded boat.

I’m thinking the 20 inch pitch should be perfect. (??)

My question – Does that seem like a big jump, going from a 19″ pitch at 6500 RPM to a 21″ pitch and getting only 5600 RPM’s? Or is that fairly normal?

Thanks!

Hi, I had the same boat/motor 2005. Your speeds seem high to me, is that gps speeds or the boat gauge? The best I ever did was 42mph with light-light load in a small chop.I was told that engine should be at about 6200rpm and I had a 21 stainless that I swapped out the factory 19 Hustler. Hope this helps.

Thanks…

GPS speed. Also a 2005. Best top end GPS I have gotten was upper 40’s (45-48 ish) with my original aluminum prop (before breaking it of course) and super calm water. I’d always top out at 6200 rpm’s with the original prop. I’m really hoping to get back to “original” preformance. I assume that if the 19 was too high rpm’s and the 21 was too low, then the 20″ pitch hopefully will be juuuuuust riiiiight….

I guess I’m assuming that they make a 20″ pitch prop in aluminum….. ?????

For my own sake, are all of the props you are trying Aluminum? Just wanted to make sure because there will be RPM/Speed differences just by switching material (SS vs. Aluminum). Are they all the same brand, model, diameter? If you start needing something in between pitches, switching number of blades will also give you those interval differences. As to why you can’t match the initial performance, that’s a head scratcher. Was there any damage to the hull, drive, or skeg that might be introducing some air into the prop path?

No damage to the hull, nothing changed… (We actually didn’t hit anything to bust the last prop – it had two weak points (nicks) on each side of one of the blades. At 42mp, the weak points connected under pressure and simply sheared the whole prop lobe off, as best as I can figure.

Yes, both of those props that I tried were the same size, brand, etc… Only the pitch changed.

Well, here is the outcome, if anyone is interested…

Prop — Suzuki calls for a 3×14″ diameter prop. The dealer doesn’t carry Suzuki parts, and originally picked a 13.2″ to replace my old one with (which I didn’t notice until the second prop, but maybe it didn’t matter that much…) ?? Or maybe that was part of the issue? But I was still getting good top end speed (42mph), just not hitting the “magic 6200 rpm”.

aluminum 3×13.2″x19 pitch = 6500 rpm.
aluminum 3×13.2″x21 pitch = 5600 rpm.

Usually, a 1″ of pitch change equates to a difference of 150-200 rpm’s top end. I can’t figure how I dropped 900 rpms with 2″ of pitch change, unless the 14″ vs 13.2 inch was the difference.

Anyway, the guy at the my dealership (actually he was very, very helpful – was great to deal with him– ) had a prop that they’d had for a few years and hadn’t fit the right boat yet… Stainless 4 blade 19″ pitch…. He thought it might just work for my situation, so he put it on and I headed to the local lake. — He thought adding that extra blade and keeping the 19″ pitch might put is in the right ballpark. Sure enough, it “topped out” right around the magic 6200 RPM mark. I gained at least 1.5 mph top end and the hole shot is pretty awesome due to the pitch and lack of flex of the stainless. Should be a sweet setup, hopefully it will continue to work well for us.

Thanks for the replies!

Glad you got it figured out! Now knowing it appeared to be an “aftermarket” prop doesn’t leave me that surprised at the wide gap between the pitches. I wouldn’t be surprised if you took two 19 pitch props from the same manufacturer and saw a significant RPM difference. Some of those aftermarket prop companies don’t consider quality control(consistency) to be a top priority. As for the 0.2″, that could actually make a 1-200 rpm difference in and of itself too. in the end, all that matters is that you found the right set-up for the boat.

Thanks — it was an interesting learning process, anyway.

It would be nice if they carried Suzuki parts, but at least we got if figured out. The original dealer where I got the boat (not my current prop source) WAS a Suzuki dealer, but the prop that was sold with the new boat/engine was an aftermarket prop as well… Weird. Seems like the dealer was being cheap in hindsight (swapping Suzuki parts for aftermarket), but maybe there was a better explanation.

Anyway, should work well. This dealer had had the prop for over 4 years in stock, so he dropped the price SUBSTANTIALLY. (Thankfully)… It was otherwise a $700 prop…Ouch!