Z9 is SLOW. Need some help

[AustinV]

2012 Z9 with a matching year mercury 250 pro XS. This is my cousins boat and I'm not familiar with Nitro, need a little setup help.

It currently has a 24 tempest that is turning around 5600 RPM. The boat maxes out around 56 mph currently. Maybe it's just a Nitro thing, but compared to my Phoenix it has basically zero bow lift. Trimmed all the way down to trimmed all the way out it barely feels like it's changing and just runs flat.

I believe P2P is around 3" but I'll have to re-measure for him. It's also on the factory jackplate which is probably 6", could be more though.

I know that boat should be hitting upper 60s. Hoping somebody has the same setup and can give some insight on what they're running so we can adjust accordingly and try a few things.

Thanks

[Fishysam]

Lower the motor to 3.5" take all heavy stuff out of the front and take it back out and run it all trimmed up

[Flippin 416]

25P Tempest set at 3.5" BP will likely be the best prop for that setup. The 24 might not be enough to maximize the performance of that year and hull.
I had a 2013 and ran the 25P Tempest and saw 67 68 and could touch 70 by myself with a light load.

You also want to make sure you are getting wide open throttle. Check the linkage to make sure it's opening all the way. 5600 rom seems a little low....I start there first.

[BMCD]

almost sounds like his motor may have lost an ignition coil. ALL my previous Z9s were 68-70 running a 25p tempest. Highly suggest changing the fuel filter. Easy to do and eliminate a potential issue

[Flippin 416]

I thought about the coil thing.....but you would notice a rough running engine?

[Fishysam]

I thought about the coil thing.....but you would notice a rough running engine?

COuld be idling fine but loosing power to get it lit up at the top end...

[BMCD]

and the zero bow lift could be an issue too.

[AustinV]

Thanks for the suggestions. We’ll check some things and I’ll report back.

[matfish]

The hull of the boat may have a hook in it. Put a flat edge down the length of the hull to see if it’s bowed. It’s a hull defect on a lot of nitros in that year range. It creates a lot of drag.

[bassfisher444]

Should be faster than that for sure, but a Z9 is pretty underpowered with a 250 on it, really needs a 300 to get the best out of it. For a 250hp stick with a Z8.

[BMCD]

Not 100% sure about that above comment... it should be a 68-70mph boat.

[Bassin1981]

I know this is an old thread but have you figured out the z9 speed and lift issue? I have an 11 z9 with a 250 and same exact issues

[Fishysam]

I know this is an old thread but have you figured out the z9 speed and lift issue? I have an 11 z9 with a 250 and same exact issues

have you done what is listed above and the problem presides?

[PatriotAW4]

Does he have lithium batteries?

[Upland A5]

My boat had very similar issues. 2011 Z8, 200 Pro XS. Tried many things before finding the solution. Motor seemed to run perfect except loss of power/RPM at WOT. The solution was the adapter plate, gaskets between the midsection and powerhead. The gaskets had failed probably due to corrosion on the adapter plate surface. The fix was to remove the adapter plate and I took it to a local machine shop. They removed the corrosion by resurfacing the top and bottom faces. They took .006” off both surfaces. The problem is when these gaskets fail water gets into the tuner. My boat now gets fully on pad and I gained approximately 7 mph.