My bird isn’t flying and I need HELP! (2015 921ProXP w 250ProXS)

[bodersafa]

Pulling my hair out trying to figure out what the heck is going on with my boat. (2015 921ProXP w 250ProXS) The previous owner tells me that he hit 75MPH with 3 people in the boat and that his best speeds came w Atlas around 17-18.
First up, here are my numbers from my last 2 trips out.

• Myself w ½ tank of fuel - Atlas @ 17, 5740 RPMs = 67 MPH
• Myself & Co-Angler, Full Tank – Atlas @ 17, 5540 RPMs = 62 MPH

For reference, I’m running a 25P 3-Blade Fury. When I measure P2P, I’m at 3” (Phoenix recommended) when the Atlas Gauge is at 18. I’ve tried every Atlas/Trim setting possible from 10-20 for top speed. Performance goes down when I raise it above 18.

After spending hours reading this forum, I was convinced I just needed more wheel time with a Phoenix and this boat was a lot different than my previous Rangers/Champion. I have 50+ hrs on this boat now and have tried it all.
Was convinced that something was up with the prop (even though visually it looked fine), so I tried out a 25P 4Blade Fury. No improvement. Took it into shop, we decided to put new plugs in (even though old plugs only had 60hrs) and did a computer scan (nothing), fuel/air psi test, de-carbon power tune. No improvement

Couple noteworthy items:

1. The boat seems to be getting slower since I got it last year. Felt like it walked a bit the first few times I drove it while I was learning to be slow w the trim. I remember hitting 68 w myself/co few months ago. Now it doesn’t even get going enough to walk at all.
2. The trim gauge reaches just below ¼ before it tops out. (Smartcraft isn’t reading trim for some reason) Let a friend drive the boat to see if he could get better #’s, his first reaction was he thinks the trim isn't going up high enough.
3. Noticed the prop blades are getting some exhaust/soot on them recently. I know it is normal in the hub part of prop, but seemed unusual to see that on blades and makes me think it is running too rich.

Looking for any advice possible before I take it back into the shop @ $120 per hr. What would you try next? The motor has warranty for another month so I’m hoping to get this fixed before then.

[strokerxs]

Pulling my hair out trying to figure out what the heck is going on with my boat. (2015 921ProXP w 250ProXS) The previous owner tells me that he hit 75MPH with 3 people in the boat and that his best speeds came w Atlas around 17-18.
First up, here are my numbers from my last 2 trips out.

• Myself w ½ tank of fuel - Atlas @ 17, 5740 RPMs = 67 MPH
• Myself & Co-Angler, Full Tank – Atlas @ 17, 5540 RPMs = 62 MPH

For reference, I’m running a 25P 3-Blade Fury. When I measure P2P, I’m at 3” (Phoenix recommended) when the Atlas Gauge is at 18. I’ve tried every Atlas/Trim setting possible from 10-20 for top speed. Performance goes down when I raise it above 18.

After spending hours reading this forum, I was convinced I just needed more wheel time with a Phoenix and this boat was a lot different than my previous Rangers/Champion. I have 50+ hrs on this boat now and have tried it all.
Was convinced that something was up with the prop (even though visually it looked fine), so I tried out a 25P 4Blade Fury. No improvement. Took it into shop, we decided to put new plugs in (even though old plugs only had 60hrs) and did a computer scan (nothing), fuel/air psi test, de-carbon power tune. No improvement

Couple noteworthy items:

1. The boat seems to be getting slower since I got it last year. Felt like it walked a bit the first few times I drove it while I was learning to be slow w the trim. I remember hitting 68 w myself/co few months ago. Now it doesn’t even get going enough to walk at all.
2. The trim gauge reaches just below ¼ before it tops out. (Smartcraft isn’t reading trim for some reason) Let a friend drive the boat to see if he could get better #’s, his first reaction was he thinks the trim isn't going up high enough.
3. Noticed the prop blades are getting some exhaust/soot on them recently. I know it is normal in the hub part of prop, but seemed unusual to see that on blades and makes me think it is running too rich.

Looking for any advice possible before I take it back into the shop @ $120 per hr. What would you try next? The motor has warranty for another month so I’m hoping to get this fixed before then.

Make sure hotfoot cable has not loosened up. Have someone Mash it to the floor with the cowling of the motor and look to see butterfly is opening all the way.

[haus9393]

Definite issue with performance. Check this for reference with the motor throttle cable as I went through this last year. But mine is not even close to as bad as yours. http://www.bbcboards.net/showthread....627&highlight=

[bodersafa]

Appreciate the suggestion. I did ask them to check the hotfoot when I had it in shop recently however when I picked it up I could tell they forgot and instead told me they didn't think that was it and it should be fine if it was set correctly before.

Just pulled the cowling off and had someone hold the hotfoot down at WOT. Don't have any feeler gauges available at the moment but it appears to be way out of adjustment (or at least more than 1/16")

IMG_20200119_151255.jpg

[XChris1632X]

You mentioned you are suspect of the trim. Are you able to get a high rooster tail behind the boat? If you are, this would indicate trim is okay as you don't need to be trimming out that high anyways.

If you are not able to get a high rooster tail you could be having trim issues. This could be the reason your RPMs are low. However, I am suspect of this theory based on what your RPMs are at. I would expect if you weren't getting much trim your RPMs would be even lower.

[bodersafa]

With the Atlas @ 18 and fully trimmed out - the rooster tail is almost as high as cowling at WOT. (But after peaking at the butterfly tonight, I'm thinking I may not even be reaching WOT.)

[bodersafa]

Definite issue with performance. Check this for reference with the motor throttle cable as I went through this last year. But mine is not even close to as bad as yours. http://www.bbcboards.net/showthread....627&highlight=

Thanks, I believe I did come across your post in my research but unfortunately wasn't able to view the photos you posted. Your issue sounds very similar to mine. Was it ultimately the HotFoot or worn striker plates?

[haus9393]

Thanks, I believe I did come across your post in my research but unfortunately wasn't able to view the photos you posted. Your issue sounds very similar to mine. Was it ultimately the HotFoot or worn striker plates?

no idea what it is. The striker plates were replaced but it didn’t help the cause at all. Basically I’ve lost about 5 mph off my top
end since the boat was new and about 200rpm. I just think it’s a combo of a wearing out engine and extra weight on the bow. I added about 30lbs to my bow with a solix 12/ 360 and going from an hds10 to a 16.

[artdevilish]

Could be prop issue. WOuld have it sent to Mark and have it BB. And may need to raise it up a little bit. Also, are you running DOn's Cocktail in Fuel? Shouldn't have soot with Don's Cocktail mixed in.

[bodersafa]

Dropped boat off at the shop again today to have the throttle checked. Hooked it up to laptop and said everything is good to go with hotfoot/throttle cable, so unfortunately that wasn't it. Service advisor is also suggesting I have the prop checked out however I'm skeptical that is the primary issue because it still seemed to be running slow when I tried my Fury 4 25P (Brand New). Figure I will give it a shot because he wants to pull the heads off next which sounds expensive.

Art - Yes, running fuel additives (Quickeen + Startron) Showed him the soot on blades, he thinks it was from the de-carbon they ran on it last time I had it in and thinks it isn't a big concern.

[XChris1632X]

Did he check your trim function?

[birdman920]

Could be “ waterlogged” if someone forgot to silicone all the screw holes in the batt compartment?...., the extra weight would explain your speed loss !...

[920Bassin]

That may be the reason, I notice a lost of bout 5mph on my 920Pro last fall. I installed a new ducer and notice about at least a minimum gallon of water that was slowly leaking out of screw hole in a time frame of bout 2 days. Have not ran it since but I should know once spring arrives here in Wisconsin.

Could be “ waterlogged” if someone forgot to silicone all the screw holes in the batt compartment?...., the extra weight would explain your speed loss !...

[TritonJT]

Dropped boat off at the shop again today to have the throttle checked. Hooked it up to laptop and said everything is good to go with hotfoot/throttle cable, so unfortunately that wasn't it. Service advisor is also suggesting I have the prop checked out however I'm skeptical that is the primary issue because it still seemed to be running slow when I tried my Fury 4 25P (Brand New). Figure I will give it a shot because he wants to pull the heads off next which sounds expensive.

Art - Yes, running fuel additives (Quickeen + Startron) Showed him the soot on blades, he thinks it was from the de-carbon they ran on it last time I had it in and thinks it isn't a big concern.

If they take heads off tell them to make sure that a piston sleeve has not twisted. They had some do that back a couple of years.

[RWB9043]

I feel your pain, I have an 18 921. with a 250 pro xs 2 stroke, boat will run 70 on a good day. I have tried several props the 24 fury seem to run the best and also check your hydraulic steering for play... mine had tons, make sure its bled properly will help some. This is the first mercury i have owned and pretty disappointing.

[BeauxPete]

Same issue but on a 721. Very disappointed in performance of this boat. My 198 Champion was just as fast as this so called high performance Phoenix. I've stripped my boat down to just the cranking battery and 1/4 tank of fuel and still couldn't get 72 out of it. I have an atlas Jack plate as well and it doesnt matter where I put it or trim it's just a turd and will not turn over 5700rpms. I've spent over 1500 on props and work and haven't gotten anything. Motor checked out perfectly with WOT at 100% and still this thing is a turd. Very dissatisfied and Mercury just keeps telling me it's the prop. Seems to be alot of people having the same issues which leads me to believe it's something more than just prop.

[Hooked247]

Could be prop issue. WOuld have it sent to Mark and have it BB. And may need to raise it up a little bit. Also, are you running DOn's Cocktail in Fuel? Shouldn't have soot with Don's Cocktail mixed in.

Maybe the prop hub slipping? Just because the prop is new doesn't mean it can't happen. I'm just guessing to help your cause.

[Lape0019]

Doubt your hub is slipping but without the props being blueprinted, even when new, there is a variation between blades and none will be exactly at 25p.

Also, I wouldn’t expect a 25p 4 blade to be much faster than a 24p if you’re not hitting max rpm with the 3 blade.

Now for the pulling heads. My buddy has a pro XS as well on his Nitro. It used to run 70 without a problem. Then, every year it would get slower and slower until it would barely run. It ended up being the reeds. He’d chip one and it would slow down a bit. Chip another and a bit more until it got to the point of really affecting the motor. The tech put a set of brocato reeds in (after a lot of trial and error from the tech as well as complete maintenance things that hadn’t been done) and he was back in business.
This would also explain why you went from the boat walking to not anymore. I know at least two people this has happened too and reeds solves the problem.

Obviously I can’t guarantee that is the problem but if your tech is already talking about taking the heads off, this is more than likely what he wants to check.

[bodersafa]

Doubt your hub is slipping but without the props being blueprinted, even when new, there is a variation between blades and none will be exactly at 25p.

Also, I wouldn’t expect a 25p 4 blade to be much faster than a 24p if you’re not hitting max rpm with the 3 blade.

Now for the pulling heads. My buddy has a pro XS as well on his Nitro. It used to run 70 without a problem. Then, every year it would get slower and slower until it would barely run. It ended up being the reeds. He’d chip one and it would slow down a bit. Chip another and a bit more until it got to the point of really affecting the motor. The tech put a set of brocato reeds in (after a lot of trial and error from the tech as well as complete maintenance things that hadn’t been done) and he was back in business.
This would also explain why you went from the boat walking to not anymore. I know at least two people this has happened too and reeds solves the problem.

Obviously I can’t guarantee that is the problem but if your tech is already talking about taking the heads off, this is more than likely what he wants to check.

You are correct, the tech is wanting to check out the reeds next. He mentioned they had another 250 Pro XS in not long ago with the same issue.

Quick update - I dropped my 25p Fury3 off at a prop shop the other day to have them check it on the pitch block. They did say it was way out of pitch and balance was off. Hopefully that solves it. Should get it back any day and will go run it right away (wind permitting).

Appreciate all the replies.

[bodersafa]

Did he check your trim function?

Yes he checked out the trim and said it's working fine