2000 P3 - Really confused

[Jbird62]

I have a 2000 P3 with an 2000 Optimax 200. 6" jackplate and a 25 Tempest prop. I have never messed with the engine height in the 8 years I have owned it. I usually can run around 64-65 MPH with full tourney load and partner at 5300 RPM. After reading recent treads, It looks I should be able to get 70 or so out of this boat, so I decided to check my engine height and found I was 5" Prop to pad. Took it to the lake and started adjusting. After raising the engine up to a total of 1", I had increased RPM's to 5500 and dropped the top end speed to 51.8. I quit right there ad returned back to normal position until could figure out what happened. RMP increase was expected, but not the top end speed drop. Any one have any ideas of what caused this? I was expecting to have to adjust it up another 1/2"or so to get it dialed in.

[SONNN]

I dont know much about props and all that, but I have a '00 P3 with 200 Merc EFI. With myself (240lbs), my pops (260ish lbs) and a full load of gear and full gas we hit 69 and i wasnt topped off yet. Hope that somehow helps...

[J Risco]

I have a 2000 P3 with an 2000 Optimax 200. 6" jackplate and a 25 Tempest prop. I have never messed with the engine height in the 8 years I have owned it. I usually can run around 64-65 MPH with full tourney load and partner at 5300 RPM. After reading recent treads, It looks I should be able to get 70 or so out of this boat, so I decided to check my engine height and found I was 5" Prop to pad. Took it to the lake and started adjusting. After raising the engine up to a total of 1", I had increased RPM's to 5500 and dropped the top end speed to 51.8. I quit right there ad returned back to normal position until could figure out what happened. RMP increase was expected, but not the top end speed drop. Any one have any ideas of what caused this? I was expecting to have to adjust it up another 1/2"or so to get it dialed in.

More than likely your prop is the issue. It either needs work or you need a different one to be able to run it higher. What prop is it?

If you are in Fayetteville, NC you should consider coming to our prop test and tune day at Kerr on March 5th. If you have a flo-torq hub system (or can borrow one) there are going to be a bunch of props there to try and people that know how to set up a boat to help also!

[Jbird62]

I live in Fayetteville, AR. It is a 25 pitch Tempest. I just had it re-worked last fall. I really wasn't interested per say in getting the boat to run as fast as it could, I was just looking to improve on what I was getting. Wouldn't raising the motor 1" improve to speed regardless?

[J Risco]

I live in Fayetteville, AR. It is a 25 pitch Tempest. I just had it re-worked last fall. I really wasn't interested per say in getting the boat to run as fast as it could, I was just looking to improve on what I was getting. Wouldn't raising the motor 1" improve to speed regardless?

It should, unless your prop is loosing grip. Raising it one whole inch at a time is a large adjustment, try 1/2" higher (so 4.5 under) and see how it does. Who worked your prop? Post a pic of it if you could.

I would ask a friend with a similar prop if you could try it one day.

[Jbird62]

I didn't raise it the whole inch in one swoop. At 1/2 inch I was running 62.5 at 5400 RPM

[J Risco]

I didn't raise it the whole inch in one swoop. At 1/2 inch I was running 62.5 at 5400 RPM

Something isnt right, try to find another prop to test. The BassCat hulls really like the fury, a Tempest can run well on them also though.

[JayLaw]

Are you sure your measuring the prop to pad properly? 5 inches is an awfully low motor. Can you post pics of your jackplate and what holes the engine is mounted to the plate.

[bassn5150]

Something with your setup isn't quite right. I had an 01 PIII w/ 200 EFI and it would literally fly. Like you, I was running a 25" Tempest. With a moderate load it would show mid 70's on the speedo all day long. At WOT, my rig ran best at about 5600-5700 RPM. As has been mentioned, I would start with running a known, good factory original prop. You could also be over-trimming while running. The Cat has plenty of lift and as a rule, doesn't require full out positive trim to make them run.

[Jbird62]

In measuring prop to pad, I placed a level on the very bottom of the boat (dead center) at the back. I then leveled the boat using the jack an measured from the ground to the top of the level which was against the pad. I then placed the level on the fin (not sure what it is called) ad trimmed the motor down until level and then measure from he ground to the center of the prop.

Here are a couple of pictures of the jackplate an where the motor is mounted to the jackplate.

[bassn5150]

Although most will mount the engine to the jackplate or transom using the second hole on the motor mount, you're not way out of place either way. What does your water pressure read at WOT w/ your current setup? I'll still say try to beg, borrow or steal a known good factory original prop and give it a whirl. Then see where you stand.

[Jbird62]

water pressure running around 25 PSi

[bassn5150]

Raise it up to at least the high point you mentioned you were at previously at. Then work from that point. You have plenty of water pressure to work with at this point. Also try making your runs with less positive trim and see what you get. Too much trim actually will cause underperformance. Keep in mind, when you are really hooked up and hauling, you should have little to no rooster tail. A tail higher than the engine is wasting forward drive.

[sacrtrain]

Raise it up to 3" and go for a run. Start way under trimmed and slowly work up. It sounds like you're getting a ton of slip. Possibly could be a hub issue too.

[Jbird62]

thanks for the feedback. I will try these and let you know what I find

[Bass Cat Boats]

First.. ALWAYS FIRST is steering torque and getting the plate to where there is just a touch of steering torque.

Then concern yourself with hole shot.

No matter the propeller and hole shot, performance is best measured by limited steering wheel torque. That is lessened by lowering the propeller and gained by raising the engine.

Once you have reached optimum performance with whatever propeller, then you can begin working on the bottom end and hole shot. Which is achieved by regulating PVS venting and exhaust rings.

If that means changing the propeller, then is be it and the process starts all over.

[Jbird62]

"No matter the propeller and hole shot, performance is best measured by limited steering wheel torque. That is lessened by lowering the propeller and gained by raising the engine. "


BCB - I am unclear on how I need to approach your suggestions. Do I keep the boat trimmed down and find the height adjustment that gives me the least amount of torque and then adjust trim to see what kind of performance I am getting with that prop?

[OldTimer57]

They are saying first, level motor trim. That is ALWAYS the right setting within a fraction. THEN raise the jack plate until you begin to detect steering torque where it gets harder to turn left. No higher. Then begin to play with settings using gradual changes. Higher on the plate means more torque, probably more RPM, and at some point, more slip and less speed. Lower on the jack plate reduces steering torque, RPM and will eventually reduce speed due to increased drag.

[Jbird62]

OldTimer57 - when you say level motor trim are you referring to the trim setting on my gauge that resulted in my motor being level i.e. parallel) to the pad when I was measuring the prop to pad?

Hope I don't come across too dense . I appreciate everyone's patience and input on this wile get it sorted out.

[OldTimer57]

Level the trim at running attitude on water. You want prop shaft parallel to surface of the water. That's why I suggested having a handy reference point such as "Mercury" decal if you have a merc. Too far down buries the nose, too far up throws water up rather than producing forward thrust.. Run like this while adjusting motor height with jack plate. IE start low on jack plate, run with level motor, turn right and left to get a feel for steering torque (which will be minimal with the jack plate set deep. Keep raising it in 1/4" increments until you notice it becomes a little harder to steer left than it was on the previous setting. Stop there for the moment and drive it a bit adjusting trim for max speed. Then you can go up or down on plate, slowly (1/4" again) to tweak speed.