Z-18 W/ 150 Four Stroke Prop Size?

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Chris Walker

Active Member
Joined
May 21, 2016
Messages
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Location
Florida - Central
Hello gentlemen,
I've had my new Z-18 four a few months now and it's still struggling to get on plane with a full tank of fuel and livewell. Dealer told me it would get better once the motor broke in but it has not. My Merc 150 four stroke came with a 22P three blade prop from nitro. This seems huge. Top speed is 53 with just me, an empty livewell and nearly no fuel. Definitely not the 60mph advertised.
Anyone out there running anything different on their z-18 with better results?

Thanks
Chris
 
Chris
I'm running the same z18 (2019) as you with top speed at 60+. That's with two people onboard (no livewell water). Comes up on plane pretty damn quick. Much like their advertising video. Call Mercury tech folks.
Vic
 
Chris
I'm running the same z18 (2019) as you with top speed at 60+. That's with two people onboard (no livewell water). Comes up on plane pretty damn quick. Much like their advertising video. Call Mercury tech folks.
Vic

Is that with the 22p prop? And are you getting that 60 mph reading on the gauge or gps? My gauge says 60 but Gps says 53.
 
Chris,

I added an SE Sport 300 hydrofoil onto the cavitation plate on my 2017, Z18. I've written about this before- some folks don't like using them but I've found it to be extremely efficient. This one in particular, I have used for more than 10 years now on two different boats. The Z18 is heavy fully loaded- live wells full, 40 gallons of fuel, and a 200 pound passenger is a considerable load for the 150. I agree with you- there was no jump out of the water hole shot takeoff fully loaded. Using this hydrofoil- I NEVER exceed 3500 RPM to get on plane easily under any conditions. if you decide to try one forget about the clamp attachment- bolt it directly to the plate per the instructions and template provided (template is great for perfect install) 4, 1/4" holes drilled is all that is required for a permanent application with no worry of it coming off. I wouldn't consider running my Z18 without one now. All GPS numbers- top speed for me has never exceed 61MPH under optimal conditions. Upper 50's is consistently there loaded or not. I run the Atlas Hydraulic jack and it doesn't matter where it is- upper 50's at variable heights. the Z18 is a super fishing boat- I'm age 64 and have owned many different glass boats up to 225 HP. The Z18 is a super boat- It's always about compromise somewhere, but overall I'm very happy with mine approaching 2 years use now.
 
Thank you for your reply that was very helpful. I'm dropping her off at the dealer tomorrow to see if they can figure anything out. I don't have a jack plate but I do have dual power poles. I captained two high school anglers this past weekend and with half a tank of fuel and those kids we could not get on plane. It was very embarrassing for my brand new $40000 boat not to get on plane.
 
Some years ago i had a similar problem with a 90 4 stroke had trouble getting on plane. Took it in and it turned out to be a timing issue totally different boat once that was fixed
 
I haven't tried the GPS speed, just the factory gauge. I'll check both when I'm back on the water.
I've never discussed boat speed with the dealer. Actually my only problem to date has been trailer tire vibration.
Vic
 
The Nitro speedometer was 3 mph faster at 60 than iPhone gps. 2 mph faster at 20. Although I don’t know the error on gps speed.
Vic
 
Wow! The Z18 performs well, normally, with a 23 pitch prop. moving to the 19 would certainly produce the result you see with a max speed of 50. Thanks for sharing what was done. In truth, under most conditons, to run near 60 you have to be trying to get to that speed. 45-55 MPH is generaly where you will be 90% of the time. That said, you are in that range now and probaly have a really strong hole shot on the take off, even fully loaded.
 
Well gentlemen, I have figured out why my boat has been going so slow. It’s a shame to figure it out now because I’ve already gone from the 22 pitch prop to a 19. I just got my boat back from it’s one year service and I asked the dealer to check the throttle cable pull.. It was not set correctly from the factory and I was never running with a wide open throttle. The boat now will hit 55 mph GPS at 5800 RPM with a 19 pitch propeller. I bet if I went back to the factory 22 pitch I would get my 60 mph. I just figured I would share what we found out. It’s a shame the dealer couldn’t figure that out when I initially asked.
 
I was suspicious of this situation and I believe that others are dealing with this same issue.
You are correct- It's really sloppy work to release a boat with something like that not done properly and checked. I would try to make the dealer get me back to whole on the issue. I believe that the 23 pitch is the most effecient prop for the Z-18 with a 150 four. You need to share this information far and wide. I've seen others on this site struggling with this same issue. Somewhere here recently I suggested that this situation could be the issue.

Sure glad that you have it figured out now!
 
Hey Chris here’s a little insight on my setup. I have a 2019 Z18 with a non ProXS 150 fourstroke. Initial setup came with a 22 pitch tempest plus & I could get 57.9 MPH GPS & was actually getting 5900+ RPM’s. I talked with my dealer & they let me try out a 23 pitch tempest plus. The 23 pitch killed my hole shot a little bit, I can come on plane in about 4.8 seconds but I’m able to run 61.1 MPH GPS now at 5700 RPM’s. I start seeing chine walk at 58.5 MPH. That’s with just myself at 180lbs, an average fishing load, and 3/4 tank of fuel with empty or full livewells. It ran the same either way. I plan to install a 6 inch atlas hydraulic jack plate. I hope to see the jack plate give me a quicker hole shot & possibly even 2-3 more MPH getting the motor back a little further in cleaner water. We will see.
 

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