Looking for suggestions for additional speed

[Phenix LABC]

Hello All,
I have a new to me
2007 Champion 200
2007 Mercury Optimax Pro/XS 225
Bob's Machine Champion hydraulic Jackplate
Tempest Plus 25P (48-825866)
I'm only able to get 51000 RPM's while doing 61 mph WOT
Seems to me that this should be a near 70 mph boat with the correct set-up.
Suggestions?

Thanks
Robert

[ChooChooSnakeMan]

I don't know your hull specifically but I agree that near 70 should be expected out of a 20' glass boat with a 225. First question - is your speed GPS or speedometer? Speedometer readings can't be trusted. 61 mph if GPS at 5100 rpm is about right, maybe a little low so not being able to get to 5800 rpm with the extra lift that would give you is the issue. I suggest a starting prop to pad of 3 1/2" and then work up but keep an eye on water pressure. If you are already close to 3 1/2" then there may be an issue with your engine not delivering full power. Perhaps as simple as a throttle adjustment or a more serious fuel delivery / electronics issue. To see the full performance of you boat you have to get the engine rpms up close to the engine redline. Other culprits could be how the boat is loaded (too much in the front) or just too much stuff in general, water logged hull (not likely but can be an issue). Not questioning your driving skill but trim plays a part. To get to the engines full rpm the trim must be set right as in trimmed up. I don't think you are over trimming because your rpms are low. Some hulls will ride flat and seem to be performing well but there is too much hull friction with the water. You have to get the nose up to get the hull out of the water and then it will break free and "fly". Your prop is the connection to the water so look it over closely. A prop in bad shape will never perform as it should and I've learned that it doesn't take many nicks to really hurt performance. Good luck.

[Phenix LABC]

Thanks for the feedback.
My Champion 200 has the same basic hull design as the Champion 198, 19 feet 8 inches.
Speed is GPS.
When you say Prop to Pad of 3-1/2 inches are you referring adjusting the hydraulic jack plate? I've tried adjusting that on the fly and it does doesn't seem to change the speed much more than 1 or 2 mph difference once I'm running on pad. As far as trim, I've tried adjusting that on the fly as well and I found that it also runs fastest when it trimmed nearly all the way up. When starting off, hole shot, the boat does best with both the jack plate and the trim all the way down.

[chad202]

Sounds like you're possibly running on 5 cylinders. I'll check spark plugs or coils. If those are good, check the fuel system.

[ChooChooSnakeMan]

Thanks for the feedback.
My Champion 200 has the same basic hull design as the Champion 198, 19 feet 8 inches.
Speed is GPS.
When you say Prop to Pad of 3-1/2 inches are you referring adjusting the hydraulic jack plate? I've tried adjusting that on the fly and it does doesn't seem to change the speed much more than 1 or 2 mph difference once I'm running on pad. As far as trim, I've tried adjusting that on the fly as well and I found that it also runs fastest when it trimmed nearly all the way up. When starting off, hole shot, the boat does best with both the jack plate and the trim all the way down.

Prop to Pad would be the measurement in inches from the center of your prop shaft to the bottom of the pad section on your hull. If your rig was mine I'd level the motor so that the prop shaft is parallel to the pad surface on the hull. Do this in your driveway. Measure from the pad surface of the hull (the pad is on the back right at the transom and centered on the hull) to the ground and measure from the center of the prop shaft to the ground. Subtract and find out what the current prop to pad measurement is. Adjust your jack plate to make it be 3 1/2" and note the jack plate setting. Get on the water and get up on plane with the jack plate set to give you 3 1/2" and then trim up until you lose speed and then bump it back down. Note the speed and raise the jack plate about 1/4" and repeat. You will find your optimal setting and know what your best WOT speed is. You just have to be careful that you don't raise the jack plate too much so your engine can't get any cooling water and of course watch your rpms so you don't over rev the engine although it should limit itself. Your best hole shot is always going to be with the engine tucked (trimmed) all the way down. If your current best WOT speeds are trimmed all the way up that may be an issue. My Skeeter likes a lot of trim but I can over trim it and I lose speed. Instead of the engine thrust going straight back and pushing the hull efficiently the over trimmed motor wastes energy trying to lift the bow. I hope this help you. First thing is to make sure you don't have an engine power issue.

[Phenix LABC]

Thanks
i figured out that a setting of about 2 on the hydraulic Jack plate gets me at 3.5.
now to try it out this weekend. YouTube videos are wonderful at showing how to do the prop to pad. Thanks everyone.

[Ed R]

You may need trim extenders or 5 degree positive trim wedges.

[Rangerdeepv]

Could be 25p is a little too much prop?