ZX-190 with Yammie 175 HPDI

[Warpath]

I am running a 2007 Skeeter ZX-190 with a 175 HPDI. 12 inch jackplate, 25M prop on the third notch of the jack plate. Getting 63 miles an hour, but I feel like she has more, and judging from others' numbers I'm right.

My question is this. I am still getting mid 20's on the water pressure, so am I safe in raising the motor trying to get a little more speed? Or should I do something else? At what point, should I definitely stop raising the motor (water pressure, chine walking)?

Thanks!

Eric

[Jason Hale]

Yes, you can go up. What RPM's are you turning now. We have had a couple that the hot foot stop was keeping the engine from WOT, so you might check that first and you may get a couple hundred more RPM's and MPH.

[Warpath]

I would say best estimate is 5200 to 5400 rpm's. I guess I'm surpriused to see some guiys running a 25M on 225's and such. I would think they would turn a much larger prop.

Eric

[Phippy]

Eric, if you want to see 5800 rpm's you need to raise your motor to 2 1/4" below the pad. To make it easy the inner plate should be about 2 1/4" higher than the outer plate or if you want to use the circle notches on the plate I have 9 showing. This should get you to 65 pretty easily and even faster with cooler air temps.

[Warpath]

OK, thanks a lot for the information! I appreciate it.

Eric

[Camalama]

I am sitting near that 2-1/4" mark and find that I cannot trim it all the way up without losing water pressure. at 2-1/2" Water pressure was fine, so it's fine tuning time. I haven't had it out with a slimmed down load, but I was sitting at 65 with full tanks, full load and two people. I've hit 67, but am hoping to get a bit more out of the ol' bug.

Oh, also, I thought my hot foot stop was my issue, as I was like you, only getting about 5300/5400 out of it. Turns out, the motor comes from the factory at 4.25" below pad. I started cranking it up and the RPMs came right up with it. Right now I'm at 6000 but loose water pressure. I'll drop it 1/8" and hopefully I won't have to touch it again.

[Warpath]

That's great to hear Camalama. I'm thinking I'd like to hit that 5800 rpm range and go from there. I plan on fiddling this weekend when I get a chance. Thanks!

Eric

[deer0373]

I would say that you have some room to move up on the plate. My water pressure generally stays around 15-18 while at WOT. I'm running the same rig (03 model) and prop and have my prop/pad set at 2.5 below. Best I have seen with 2 people, full fuel, empty wells, has been 66.1. By myself, it'll run around 67-68.