4" above the bottom???

Pantera24,
Two years ago when I was putting my boat in the water for the first time I was using 30" pitch props. I had a set of 28" props that I had JUST sold before I tested the boat to a guy in NJ because I knew I wouldn't need them. At about the time I sold the 28's I had JUST purchased a pair of brand new York labbed 32" props prior to testing the boat because I felt they were what I needed! Come to find out on the mainden voyage I could only turn 4900rpms at WOT(wide open throttle) with 30" pitch props----I was shocked and confused! So I called up the guy with the 28's and asked if he wanted to sell them back to me and he wasn't going to be able to get his boat running that year anyway so he sent them back and I put them on untill I recieved some brand new 28" York labbed props! I knew I couldn't turn the new 32's so I didn't even try them and Joe Skrocki (Audacity) bought them from me. The labbed 28's put me up to about 5200-5300rpm. About 6 weeks after I had been running the boat we found out that the throttle linkage wasn't opening up all the way and was cheating me out of about 100hp or so. So, after ALL the prop testing, $$$, TIME, AGGRIVATION, I have sold both pairs of the 28's still have the 30's and now own another set of 32" labbed props. The 32's turn at about 5500-5600rpm---which is what I originally needed to begin with!

So do yourself a favor and check the throttle linkage FIRST before you go crazy on wasting your time and $$$ on other stuff!

BTW, My boat is a 32' Active thunder and I had a pair of dyno tested 540's that were making about 630hp @5400rpm when all this was going on. So at the time I was just about as confused as you are now!

KAAMA - that is GREAT advice. I wish I had all the hours back in my life from working on stuff and then I found the SIMPLE problem!

Especially from those stupid snowmobiles!

That is the exact same advice that Jo from Pantera just gave me. I checked the linkage and it appears to be at the exact location as when I pulled the motor, according to the digital photos I took. But it may need adjustment.

I will attempt to adjust it this week when I can get the boat out. I'll be both pleased and pissed!!!

I hope its the throttle/linkage as the motor runs smooth and strong, as it did on the dyno. Just too low of RPM with a moderate prop - 28P. And on the dyno under load I could pull up to the soft touch limiter 5400.

Thanks for the "Story" it may have saved some real aggravation for me!

Kirk

Kirk, did you do something different to the motor or did you decide to dyno it just to see wht it had? What exactly is your motor? Supercharged or NA?

I would think you should be running low 90's in the right conditions! I love those Panteras.

Is your engine making the same power in the boat as it did on the dyno? What is different? Exhaust, fuel pump, water pump ect. I had one MPI engine dyno at 600 but when put in the boat she ran pig rich and made no power. Did you look at the plugs? What are the engine specs? Fuel pump, tank pick up size? Is the engine getting enough air?

I agree with GEOO, it's usually best to try and dyno with the same equipment that you will using in the boat i.e., carb, distributor, fuel pumps, ignition boxes, etc, etc....even the type of fuel you plan on running. When I was at the shop of the guy who was doing my dyno testing, I brought in 2 different kinds of fuels in 6 gallon gas containers. Anyway, it can be the little things when transfering the engine(s) from the dyno to the boat. Some installations have more problems than others while getting the bugs worked out and getting it dialed in properly is all a part of it as you know.

Soon, you will be able to enlighten someone else who's having problems with your experiences that you have had with setting up your boat. Selling used or un-needed parts and giving helpful advice to others--- I believe that is one of the better reasons of what this website was initially intended for.

Everything is the same, fuel pump, water pump etc..except the exhaust, but it is open with Imco Powerflow Manifolds.

The intake air and throttle position are the (2) I need to check. Plugs look very good, actually I dropped down in temperature range and got too much soot, so i went back up.

Thanks for the ideas. I'll let you know what I find.

I would double check your tach. That 5% slip number is still a little suspect to me. 78 MPH would make sense at 5000 or 5200 RPM, but at 4650 it doesn't add up. Also did you dyno the motor with the same exhaust and all accessories on the motor? Dyno headers and no accessories could easily be 50 to 75 HP. Personally I don't think 78 MPH with 650 HP is all that bad in a 24' vee. Just my .02. Good luck and keep us posted!!

Kirk,

How did you verify it was a 1.5 ratio? Did you actually check it by spinning the motor or did you look at the tag an the drive. I was thinking that maybe the previous owner switched to a 1.36 when they did the motor work. That would explain why you can't pull a 28 and how you're getting 78 mph at 4650 rpm!


Just a thought.