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RPM Question on 454

C

cooter

Well-known member
A little info on my situation...

I have bought a Stump Puller to go on my airboat, and set it at the Starting Degrees Whirlwind recommended. No problems it is on, and have given it a test drives everything seems good here.

I bought the Airboat back in November with a 10 blade Warp Prop on it, and changed to the Stump Puller. From day one with the Warp it would only turn 3800rpms (Engine), changed to the Stump Puller and it moved up to 4000rpms (Engine). So I have bene searching for why it wouldn't get the rpms up and the carb all the way open.

Well, Finally figured it out, made an adjustment and BINGO, the Carb is 100% open, and now I am getting 5500 rpms (Engine). I need to be able to run a sand bar or two, but nothing long or no hill climbing. Bascially pulling onto a Sand Bar, and pulling off. I haven't run it (Tested It On River) since I found the problem, but kinda figure the way it was acting on a Strapped Down Trailer that it would just about run what I need and probably then some.

Question:

(1) Is 5500rpms to much to run the 454 at ? ? ?

(2) What would be a good rpm to add to the life of the engine, but give me a good chance at the Sand Bars ? ? ?

(3) Increasing the pitch on the prop is the way I need to take rpms off the engine, CORRECT ? ? ?

Like I said, I'm a Rookie, so don't think I have any idea. Explain it so your kids can understand. :scratch: Sorry for being a Knothead, but I feel like I am pretty close, or within an adjustment or two, and don't want to screw it up, or run my engine harder than it is really built to run. Thanks for ANY help. cooter
 
yes... to lower your rpm add pitch. What gear box ratio or belt box ratio are you running? I run a 2 blade stump puller on my dd boat with a 500 caddy. My wot rpm is only 2600 rpm but it pushes awsome. I did have it at 2800 but I think it pushes almost as hard and is a lot quieter the way I have it now. Only thing I notices is it doesn't spin up as fast. I think (not knowing) that the slower you turn your engine the longer it should last. But you probably want to stay in your power band.
 
When I talked to Whirlwind on my prop I asked what the sweet spot is "usually" on the stump pullers. I knew the Max safe rpm was 3000 but no one wants to run them there because of the noise. She said the SP blades like to run around 2700. So I think your 5500 with 2 to 1 is probably close. It's mostly going to be trial and error for what works best for you. Someone else will probably chime in on the longevity for the 454 at those rpms. Also you will probably rarely see the 5500 rpm if you don't run dry alot. You will probably cruise at 3000 engine rpm or less.
 
My 454 is going on 10 yrs, with heads redone 4 years ago. DD so the engine only turns 3000 or less. I love this set up.
 
Cooter,

I got a 454 too, lot different set-up with long belt and C.R.

I agree with everybody above, 5500 will shorten the life big time on that engine.

I spin mine up to around 5100 max and I keep it there as short of time possible.

Basketcase
 
I would throw a little pitch in it, the engine will last longer,gas will last longer, less noise. as far as dry runnin, if you do alot of dry runnin keep it where it is, put some pitch to it and it will just take a few seconds longer to start moving dry. Let us know what works best for your application I'm curious, I'm thinking about building a bigger boat.

John
 
Seems like 5000 rpm's is what I am being told more than not. Talked with Harold Spee the other night, and he made the same suggestion. I'll add a little more pitch and then it should be about time to test it out on a sand bar.

I don't run dry much, but I would like to park it on a snd bar when I am hunting & fishing, then be able to push back off when I am ready to head home. I doubt that it will be more than that. which will bring me to my next questions "New Thread" cooter
 
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