Suzuki 2008 DF 225 not going over 3000rpm

[Seahunt22]

I am new to this forum and need some feedback please. I have had an issue with my 2008 DF 225 Suzuki since April. I do all my own maint and this past April did a complete service: oil & filter,water separator, both thermostats,plugs, in line fuel filter, lower unit oil, impeller/water pump & zincs. When I launched the boat, I started having an issue with accelerating over 2800-3000 rpms. I then changed the plastic fuel filter bowl noticing that due to the Ethano gas, it was out of shape. I also changed the high pressure fuel filter just to be safe. It ran fine for a couple of weeks and then again, same issue. This time even worse. I had no other choice but to bring it to my local Suzuki dealer. They did a diagnostic and ran it under a load and said it was the fuel pump, which they replaced ($$$) and also replaced the fuel sender assembly and the filter. When I got it back, the boat ran great. Went fishing a few times and it was on the money. Last week I went to take it out and when I went to accelerate over 3000 rpms, it wouldn't go. Up to the 3000rpm, it ran perfect. Not a miss or anything. I even tried it from a dead stop and just went full throttle and it didn't move. The mechanic told me to try and put it in gear and see if it starts. If it did, we may be talking about the Neutral Safety Switch. I tried that and it did not start in gear. I am at a point where I don't have any idea what it could be. I have been using the non ethanol gas since then. I would really appreciate some help or input here. Could it be a shift position sensor? Thank you all!
Mike

[keakar]

patience grasshopper, you just posted this exact same thread only an hour ago so why make a new one?

give people time to get off of work and read the forums, by then you will begin to get some responses

[Seahunt22]

Sorry about that. I did not realize I did that. I was just navigating around the forum. Must have clicked something I should have not.

[Moonlighter]

Neutral throttle position sensor on the engine may be out of position, broken or faulty. That would explain the symptons. It is a quite inexpensive part to replace.

A further question that may not seem relevant, but is: do you have a NMEA2000 network on this boat, with the Suzuki engine interface connected? If so how long ago was it installed?

[Seahunt22]

Moonlighter,
Thank you for the response. I am going to check into that before I pull the boat out and bring it back to the Suzuki dealer. I will let you know how I make out. I d not have a NMEA 2000 interface onboard.
Thank you very much!
Seahunt22

[Moonlighter]

Ok, no NMEA network rules out one possible cause.

Got your email message too.

Now, have a very careful look at your fuel lines. They could well be the problem! Re-reading your original post you mentioned that ethanol fuel has been used.

Ethanol does bad things to the insides of the fuel lines, causing them to swell, go hard and break apart and you cant see the damage because it is to the inner liner of the hose. One way to check is to carefully feel along the length of the lines, bending them as you go and feeling for any hard spots or sections that are less flexible than other parts. Also try to feel for any cracking that might indicate hardened liners inside.

If in any doubt, replace with quality ethanol resistant marine fuel lines.

Given the symptoms of not revving fully, it is sounding like a fuel restruction now more than electronic, so I reckon the fuel lines might just be the culrpit!

If that doesnt turn up anything, I think the neutral throttle switch on the engine is worth a close look. I have seen the occasional report of them doing weird things when they are in the process of failing.

[Seahunt22]

Moonlighter
Your the best. Thank you for the quick response. I will check out those fuel lines and see if there are any issues there. I'm going to have to go step by step here. Process of elimination. Will let you know what I find. Thanks a million!
Seahunt22

[Seahunt22]

Moonlighter.
Took the boat out twice since my last post to you. It ran great but still will not go over 5400-5500rpm with the throttle wide open. I check the fuel lines from the motor, the ball pump and any other lines I could get to and nothing seemed to be a problem. I took off the top plastic cowling on the motor and could not see anything out of place. I called Browns Point Marine up in New Jersey and spoke with Paul up there. They specialize in Suzuki service & parts. He was very knowledgeable and suggested I check all my spark plugs. I just replaced them all when I serviced the motor in April. Said I may have a bad plug and that could be a reason for not getting the max rpms of 6000-6200. He also backed what you said that it could possible be the neutral safety switch sensor or the shift position sensor. I will be call my Suzuki dealer tomorrow morning to get his take on this. I may just have to bring it back there again and have them go over what we spoke about. I just want this boat to run the way it's supposed to run. Very frustrated. Thanks again.
Seahunt22

[Moonlighter]

Sounds like progress has been made, but unless the engine is missing, I doubt if it will be plugs, but you never know! Still sounds more like a fuel issue to me.

For the sake of a few $, why not change out the fuel lines anyway, this eliminates them as the problem and is worth doing every few years anyway. While you are there, fit a new fuel bulb. They can fail too. Dont get an after-market one, get an oem one. Make sure you install it so that the end closest to the engine is pointing upwards. I hate to say it, but the oem Merc and yamaha ones are the best. Suzuki ones ........

Also, does the underfloor tank have an anti-syphon valve fitted? If so, I would immediately remove it and punch out the ball and seat and spring from inside and reinstall the empty fitting to the tank - you dont need this valve and they only cause problems on outboard powered boats. Or just replace it with a suitable barb fitting.

[Seahunt22]

Moonlighter
Thank you again. I'm going to try to get some answers today from my local Suzuki service people. I know that when they changed the fuel pump, they also replaced the fuel sender assembly & the filter. I changed that fuel filter bowl along with the filter inside it when I serviced the motor back in April. One question I have for you. When you say replace the fuel lines, are you saying to replace from the tank going back and including the bulb / primer line ? Any other lines to replace? I will also have to check to see if it does have that anti siphon valve. Hopefully can solve this "mystery" this week. Thanks for your help once again. Will let you know.
Seahunt22

[Moonlighter]

Re the fuel lines, i am suggesting that you replace the lines, starting from where they connect to the tank, all the way thru to where the line from the tank connects to the engine. And replace the bulb as well. So yes, including the bulb/primer line.

When you take the line off the tank fitting, stick a piece of wire into the end of the barb fitting and if it wont go in far, it means that the fitting is an anti-syphon valve. It seems that nearly all US built boats have them.

My understanding is that the regulations only require them to be fitted to inboard powered boats, not outboards. So either punch the ball valve out as described earlier, or replace the fitting with a plain brass fuel barb. Use some stag jointing goo on the fittings to get a good seal when you reassemble.

Not sure what kind of in-line fuel filter you have, but it should be one of the Racor type filters with a clear bowl at the bottom. They have a spin off element similar in appearance to the oil filter element on your car. Normally they are placed between the tank and the primer bulb.

[Seahunt22]

Moonlighter,
I took the boat out today and it ran perfectly up to 5400 rpm WOT. Still can't get it to 6000 where it should be. I bought the neutral safety sensor, took off the side panel to the motor and could not get into where the sensor was. I did not want to start disconnecting wires. Keep in mind I have the boat on a lift and it was a little difficult maneuvering around. The main fuel line from the tank back looks as though it has been replaced; not the line from there and the squeeze pump. That's next. You would think this would be an easy fix? Not in my world. Thanks for all your input.
Seahunt22

[Seahunt22]

Moonlighter,
I think we figured it out. Thanks to your input and cross checking everything that you mentioned I took it a step further. I drained the bowl at the bottom of my Racor fuel / water separator. The fuel in there did not look very good. I also took off the fuel bowl in the front of the motor and emptied that too. Just a note to everyone out there. When you take off that front fuel bowl, it is very hard to get back on due to the Ethanol fuel disforming it. I sanded the top of it a little and put some silicone spray and it fit right back in. I took the boat out and it ran like a champ. Got it up to 52mph and 6000 rpm. I kept the old Racor filter and I am going to cut it in half to see what was in that filter. It will be interesting. I did not replace the neutral safety sensor due to the fact it look complicated and there were a lot of wires to deal with. Bottom line: fuel restriction problem. Hope fully this will help others out there. Thank you for all your help Moonlighter!
Seahunt22

[Moonlighter]

Moonlighter,
I think we figured it out. Thanks to your input and cross checking everything that you mentioned I took it a step further. I drained the bowl at the bottom of my Racor fuel / water separator. The fuel in there did not look very good. I also took off the fuel bowl in the front of the motor and emptied that too. Just a note to everyone out there. When you take off that front fuel bowl, it is very hard to get back on due to the Ethanol fuel disforming it. I sanded the top of it a little and put some silicone spray and it fit right back in. I took the boat out and it ran like a champ. Got it up to 52mph and 6000 rpm. I kept the old Racor filter and I am going to cut it in half to see what was in that filter. It will be interesting. I did not replace the neutral safety sensor due to the fact it look complicated and there were a lot of wires to deal with. Bottom line: fuel restriction problem. Hope fully this will help others out there. Thank you for all your help Moonlighter!
Seahunt22

Glad to hear you are running again!

It might be an idea to replace that racor element again after a couple of months. A dirty batch of fuel can take a while to get through. So sometimes it takes several filter element changes to get the majority of gunk out of the tank and lines.

Also, did you find a anti-syphon valve on the tank and remove it too? Again, junk in the fuel is going to cause problems with that valve so jt is best for it to be gone, in my opinion.

Cheers!

[Seahunt22]

Suzuki DF 225 rpm issues

Thanks Mate!
I plan on changing that fuel filter a few times. I am also going to check that anti siphon valve as you suggested. Really appreciate all your help.
Thank you!!!!
Seahunt22