Need Help!! Never ending issue Suzuki DF150

Easyvictor.14

New member
OK brats,I have A recurring problem with my Suzuki DF 150 fuel injected 4 stroke. 2008 model on a 23 Venture.
I’ve been in 3 shops a total of 5 times and spent over $2800 so far.
The engine will start just fine, and run for about five or 10 minutes at 3800 to 5500 RPM then it will start to stutter stumble down to about 3000 RPM and never go back.
This is what has been done: water separator replaced, fuel vents re-oriented, loop in fuel vent lines, injectors rebuilt, vapor separator tank cleaned twice and replaced once, new fuel pump $$$, and “vacuum leak” repaired (don’t know what was supposedly leaking) both tanks pulled, cleaned, tested. The engine had 85 hrs on it when I bought it 3 yrs ago from Wefings, Now has 235 hrs. Been a huge pain in my butt, I’ve even thought of selling, but I won’t do that to someone. HELLLLPPPP!!!
All but one shop are in other states, and local shop won’t honor any work, they just want to keep throwing parts at it with my credit card.
There was some water in fuel originally, came in thru tank vents facing forward. That problem is fixed.
 
Any water and debris in filter. I use a Racor water and gas filter with clear bowl to check.

Have all fuel hoses been replaced esp the ones inside the rigging tube? Hose can look good on outside but the inner hose can fail

What is the fuel pressure on the injector rail?

Do you have the factory shop manual? Any codes using diagnostic software.?

Take it back to Marc at Wefings?
 
Yes, every fuel hose and filter has also been replaced, and it does it when run from a portable tank, so it’s engine side. Don’t know rail pressure, I have to assume Suzuki dealers checked that!
The most maddening part is, it’s intermittent. Might start and run all day for several days, then start acting up. Sometimes it will clear after a shutdown for a few minutes, other times it won’t recover until it hits the shop.
 
Sounds like venting/fuel flow could be a potential culprit, but even though you've looked into that - have you tried running it on a portable tank just to make sure?
 
Easyvictor.14":2jafiqwb said:
Yes, every fuel hose and filter has also been replaced, and it does it when run from a portable tank, so it’s engine side. Don’t know rail pressure, I have to assume Suzuki dealers checked that!
The most maddening part is, it’s intermittent. Might start and run all day for several days, then start acting up. Sometimes it will clear after a shutdown for a few minutes, other times it won’t recover until it hits the shop.

Is the White E.C.M. power wire HOOKED DIRECTLY TO THE + POST OF A BATTERY, not through a switch, combiner or relay etc.?? :beer
 
It sounds like something is tripping the over-rev caution system, which on the DF150 limits the throttle to 3000 rpm. Next time it happens, try to re-set it by reducing throttle all the way to idle for at least 1 second (I'd even go into neutral, just to be sure), then see if you can get above 3000 again. That's what the Suzuki manual says, and it's the exact same procedure as my Merc (which limits to 2500 rpm). The owners manuals provide virtually no information on what sensors play into this "feature", but in doing some research, it's more than just over-revs, at least on the Merc. It seems to be a combination of different sensors and from what I've gathered, protects the engine from some kind of perceived over-load condition and can happen at any RPMs above the protection limit (3000 in your case) not just RPMs above the max RPM rating. It could be a bad sensor...Mechanics may insist bad sensors will always throw a code, but I've heard from others who have replaced sensors like TPS or CPS which never threw codes, and their intermittent problems disappeared. Just a thought since it sounds like you've already checked all the fuel systems, and since it is so randomly intermittent.

-Mike
 
OK! I’ll check the dreaded “white wire”, thanks Dave.
Also, it’s not throwing any codes, but I’ll check into rev limiter and sensors.
All the shops have focused on fuel, but I’m leaning electrical also.
 
Changed plugs already also. I’ll be back at the boat Sunday and I’ll start checking these items. It’s just frustrating to have spent almost $3000 on “repairs” that didn’t fix anything. I can’t go back to the shops because they’re behind me on the Loop, and the boat is now back in Texas for the winter.
 
Are you sure that the fuel tank, the fuel pickup, the valve if it has one, any fuel filter and all of the plumbing to the carb or EFI is clean with no blockages.

Years ago I had a motorcycle that acted just like your engine. Turned out it was a blocked fuel pickup tube.

David
 
I just bought C-Pearl a 2006 25 Crusier with the same motor as yours. I am going to be servicing myself and came across this post. Just wondering if you ever solved the problems you were having and if so what was the cause.
Thanks!
 
My Honda misbehaved due to a bad ECM. There was a service bulletin about it, but I had to point the dealer to it.

Might want to check the service bulletins for Suzuki.
 
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