Nitro z7 low rpms

[matfish]

Hey guys, I just tested a z7 with a 150 pro xs today. It seemed to run great but the rpm's only reached 5100 with the top speed being 51-52. it had a 24 tempest prop with no plugs. It also had a manual jackplate and I have zero experience with jackplates. There were three people and half a tank of gas with no gear in the boat. Any idea why the rpms and top speed would be low? Thanks

[06 SB]

Did it jump up on plane OK? Did the nose plow or was it lifted up when running at 5100? How far up did you trim the motor?

[matfish]

It got on plane well and the front end was up at 5100. The guy said that is the way it has always performed. The trim gauge didn't work so I was guessing on having the boat trimmed up by looking at where the spray was coming from. The spray came up from behind me so I figured I had it trimmed up pretty high.

[Fishysam]

A 24p prop seems to much for the numbers given. Doesn't really scare me to think a 22p would get the rpm up, a better whole shot And more top end given more rpm. 3 people in my z8 w/250 is a lot of load.

[matfish]

Thanks for the replies. I honestly don't mind the low top speed or the low rpms(longer engine life),I just hope it's got to do with the setup instead of the engine. Compression test is tomorrow.

[Joe Genovese]

I have a Z7 with a 175. It's still sluggish with 2 people, gas, gear, especially when the livewells are full. If you buy this boat contact Chris Bailey on here and get one of his hydro foils. Your boat will get on pad in a fraction of time and let you get on with business. At wide open I can have my trim maxxed to run it's best, so I'd look into fixing that gauge. I only keep as much gas in as I think I'll need. I filled it once and I'll never do that again unless I'm on vacation at a bigger lake......8 pounds per gallon adds up. I also pump out my livewells after I back in cause I usually end up with a couple gallons during that process.

[matfish]

Would any of you think that the low rpms would be an engine issue? It felt and sounded good, just didn't make it to 5400 wot rpms.

[Fishysam]

Max the trim up while going wide open. Summer heat And full load can slow you down on rpm as well.

Gas is like 6.2 pounds per gallon. It does add up, I hardly ever fill my boat as it will be slow and low on rpm from just that.

get a straight edge like 8' long and see if the bottom of the boat is flat or concave anywhere between the wheels and transom.

most of the bass boats are propped for top end speed, this changes drastically on load. They can not get it right always but it seems when they are wrong it's always low on rpm. The safe side. Keep tinkering and we can get through this

[zprice7]

I had the same issue for a while and still tinkering with mine trying to get it to where it needs to be. 3.25”-3.5” prop to pad on the jack plate is going to be your best bet with anywhere from a 21-23 pitch Tempest plus prop. I run a 21p on mine and run anywhere from 5400-5500 rpms at 54-55 mph. You should be maxing out the trim on plane.