2000 Kanga Top Speed

[eml0130]

I have a 2000 Kanga (same hull as the Outback) with the 310 carbureted motor and a brand new Acme 541 prop (13x12). With just me in the boat I can get 35mph (GPS verified) at 4800rpm. As a note this is not WOT, there is more that I could rev but obviously don't want to over rev and break the motor. Even with a bunch of people I can easily get to 4800rpm with a little more throttle that I could give it. The motor pulls strong and smoothly. Based on what I could find about the boat the top end seems slightly low. The stock prop was an OJ 13x13 but I wouldn't think going to a 13x12 would give up that much on the top end. Any information is appreciated, thanks.

[zabooda]

The 13x13 will give you about 2mph more speed and keep the rpms down. A three blade will be slower out of the hole but higher top end speed than the four blade.

[eml0130]

So here is some more information, I took my friends 07 Malibu response out this week and his tops out around 47mph, granted his is fuel injected and has a little more HP and the hulls are slightly different shapes. Would that really make a 12 mph difference? We have the same prop specs (13x12) and both have 1:1 transmissions. Is it possible that my carb is limiting my power output? I would think if that were so I wouldn't be able to get to WOT? Thanks.

[z28ke]

If your getting to 4800 rpm the power is there. What rpm was he turning at 47mph?

[eml0130]

5,000 rpm, which I know I any get to, but even at lower speeds it's off from mine. I'm at 20mph at 3,200 and his is around 2,100. I'm going to double check the ratio on my tranny but it seems odd that it would be that different. His boat is also a bit heavier.

[eml0130]

*i can't get too

[eml0130]

So I went to go verify my transmission model/ratio and the label plate is missing. Anyone have another way (without disassembly) to figure out what transmission I have? Thanks.

[z28ke]

To figure out the ratio you could turn the engine over by hand 1 full rotation with it in gear and see if the prop turns 1 full ration as well. If you call one of the prop companies and tell them what prop you currently have, and what your speed/rpm is, I'm sure they will recommend a prop for whatever desired top speed you would like.

[eml0130]

That is a good idea, I was about to try and use a photo-tach on the shaft.

My concern with this is that the boat is supposed to go faster than 35 being that it has (which I will verify) a 1:1 tranny. If its a different transmission and 35 is expected I'm completely fine with that. If I'm making power all the way to 4800rpm then the transmission is probably slipping and I will have to figure out what is going on there. I also double checked the prop nut/key to make sure that wasn't loose.

[eml0130]

I took it out tonight and it is a 1:1 transmission. I ran it, verified that the transmission fluid level was in spec, that it wasn't getting water in it (not milky) and that the fluid didn't smell burnt.

After doing a couple more test runs, it pulls clean and hard through ~3,500 rpm. I did notice that at higher rpm's it was not nearly as responsive to giving it more throttle. I am thinking something is causing the transmission to slip, hopefully it is something easy and I'm not going to get into a rebuild or replacement. I have the ZF marine transmission manual and I'm going to clean the filter. Does anyone know if you can do that without lifting the transmission? Any other suggestions?

[eml0130]

So I ended up getting a photo tach and compared shaft to engine rpm. Turns out my tachometer was bad and reading high. So now it's fixed with a new tach and I'm well into the 40's. Thanks!

[zabooda]

Yea, I tap the bezel of the tach when I get those high readings and the rpm readings drop to where it should be. The reason I do that is I permanently lost a speedo and so I will rely more on the tach especially if the other speedo drops off. Fortunately, I had a super rare find of two speeds on Ebay this week that I snagged. The seller said they worked the last time the boat was used in 2008. We'll see if I wasted my money or not.

Glad you got the issue resolved and lething us know.