i have a 2013 z7 with 150 pro xs 6" jackplate. my question is it has ran 61-62 with just me in it pretty much all the time but with in the last couple months it seems to only wanna go about 55-56 and the rpms are a little lower about 5200 cant seem to figure it out. my water pressure is at about 12psi pad to prop is 3.5 was gonna raise ithe motor a 1/4" but not sure if my water pressure will go to low. thanks ahead for any input or suggestions.
Try a new prop if possible.
Bryan McDonough
2023 Nitro Z21 XL
Nitro Team
Im having the exact same issue. I see that my motor is mounted on the second hole from the top, and this puts my below pad measurement to well over 5". I hope to hear how you resolved this! Thanks.
I wouldn't mess with the setup if it was right before check prop/motor problems before changing anything.Originally Posted by 13z7nitro
Have my boat in the shop for this exact same issue, only mine is a 150 4 stroke. So far we did find the sleeve that goes over the prop shaft was cracked and the prop was loose due to that. As soon as I know what is causing the issue, I will let you know.
Just spoke with the mechanic. They test drove my boat and think its a trim issue. They are gonna replace the trim sensor, and that still doesn't correct the problem, they are replacing the trim pump.
It could be one or a combination of things. Bad cylinder, fouled plugs, bad fuel, malfunctioning primer bulb, damaged prop, etc... OR it might just be raising your jp and fine tuning. Your water pressure isn't necessarily low right now and changing the height of the jp won't really hurt anything. Running below 12 psi at WOT is what you need to watch. If it were me, I's start by putting in a can a seafoam, tinker with the jp and see what happens.
Last weekend I noticed that when the motor was cold, I saw high RPM and speed. (~5250 WOT and ~54mph) Once it warmed up It dropped of the below 5200 and 50mph, and I had less gas in the boat at that time. Weird bug, and I hope my dealer can find/fix it.
13Z7 - Any news on your boat? Did you get ti fixed?
Mine did this and it was my coil, after 1 went out they all went out. had to get them all changed in a row. very aggravating.
Burnett, did they only see the issue after they ran it for some amount of time? I believe my issue is that they are only testing the coils cold, and that's why they all look OK. When my engine heats up after 10 minutes or so at WOT, I feel like I'm just not hitting on all cylinders.
I also called Mercury and the representative gave me some BS that they had already fixed the issue and that my issues are being caused by a bad ground. Ive now had 2 Mercury dealers look at the boat/motor and neither commented on that possibility, and both actually confirmed my suspicion of the coil quality nowadays in these motors. I love mercury, but its a shame they cant just own up to it and take care of their customers.
Mine seems to work harder in the winter as well. I have a Mercmonitor installed and nothing shows up on it so I think it is the gas blend we get in winter. My truck loses about 1mpg and noticeably less power in the winter months. I think it is April or May when the summer gas comes back. I can tell as soon as it gets in the truck. Boat takes a little longer to run the old gas out and fully replace with summer gas.
Well, they figured it out. After a lot of head scratching they found that the diaphragm in the Fuel Rail was cracked. This was also the reason why its only noticeable at high RPM's. There's a service bulletin out for this fuel rail on my Pro XS 150, its 2015-18. Hope this helps. Also, not sure if this is covered on the Gold warranty. Should find out tomorrow.
Good to know. And truck getting one less mpg is because there is more air entering the motor making more fuel needed for 14/1 air fuel ratio. But that also frees up some ponies!
I got a 2013 150 ProSX that this year just started this same thing. Last year I ran 5500 RPM about 63 alone. Im down to 53 to 54 now at 5200 RPM. I have not taken mine in yet, Ive been racking my brain on what could of happened .
FYI, the fuel rail issues are not covered by the Gold warranty...
Well, it wasnt a fuel rail....took it to the lake and it still suffered the low RPM. After a weeks the dealership figured out that the replacement coils that had been put in the boat were different serial numbers than the stock coils. They changed all the coils to the newer part number and engine ran worse. Come to find out, it was the wrong coil and a typo in the service manual. They figured out which coil to use and now shes back to normal. If any of you are still beating your head against the wall, check the serial number on your coils. I'll try to get the old serial number of the coil that caused issues and post it. I'll also post the serial number of the part that fixed it.
Following.....I'm seeing this same issue on my 2013 as well.
If you're only getting 5000 Rpms I'd say its generally a coil. Far too common and annoying.
2010 NITRO Z7
What prop are yall running on your 150's with the Z7? Ive got a 24 fury, and when Im in a tourney with full tak of gas, two guys, and full livewell Im getting low 5k range, and when Im alone with a lighter load the boat runs 5400 and ~58mph. Dealer said that boat should have come with a 23p tempest, so Im looking into that. Anyone running a 23P prop?
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