DF25 VTwin sputtering (2013)

[kristiankynk]

Hi!
About 15min of day it works fine, then suddenly starts to sputter and does not go over 3000rpm. From idle to 3000rpm works fine, but when i try to push throttle over that, it starts sputtering. Tried changing the primer bulb, no effect.
Any ideas?
PS the little white haze comes from carburettor cleaning fuel additive. The problem existed also without additive

https://youtu.be/uODMPQ4FiE8

[bklake]

Sounds like the rev limiter is kicking in. Shouldn't do that when in gear. You say it works fine for a while then starts acting up? Sounds like something electrical perhaps the neutral switch. I don't have my factory repair manual right now so can't look up where this switch is. I don't remember exactly.

[Moonlighter]

I agree it may be the neutral throttle switch on the engine that is acting up. Sounds like a race car with the pit limiter on, hey!


Possibly this part, look at the list of related fitments to see the relevant part for your engine number.

https://www.boats.net/product/suzuki...9f8a29f1034495

[kristiankynk]

I’ve been 2 times on water with this engine. On both days it let me drive in full throttle about 10-15min. And then started acting like this. I tried to start the engine when in gear (not intentionally) it acted correctly and didn’t start. That was on water at the same time. So i think the switch might be ok.

[kristiankynk]

Shorting the switch manually should indicate its fault, right?

[Moonlighter]

You should get this engine hooked up to SDS to see what codes are being recorded. Should save a lot of speculation.

[Murray]

If you plan on doing your own work I would suggest you get a genuine Suzuki Service manual, lots of information. Paper copies are around $80, you might be able to find a pdf for less online. I haven’t had to mess with my neutral safety switch but I would suggest you not jump the switch unless your sure it won’t do any damage to the ECM. The neutral safety switch is tied into the ECM somehow and it could be expensive should things go sideways.

[kristiankynk]

Thanks a lot! I’ll find a workshop with SDS.

[kristiankynk]

Our local Suzuki top guy said, that 25HP motors do not show practically anything with SDS.

[Murray]

The D in SDS is diagnostic. If the engine is going into protection mode and limiting the revs. for whatever reason, there should be a code stored in the ECM. Maybe the diagnostic features are reduced in smaller engines but one would think basic code information would be available via the SDS.

[kristiankynk]

If it goes to protection mode, then “the light” should olso light up? Mine doesn’t.

[Murray]

It should assuming it’s working correctly. How is your battery, fully charged, no loose and or corroded connections. Could be a fuel starvation issue. Have you checked all the fuel lines from the tank through to the fuel rail? Maybe a kink in a fuel line? What I’m thinking is maybe you have a restriction in the fuel system and the engine is losing revs burning less fuel allowing the VST fuel level to catch up? It’s something you can check that won’t require a trip to the shop.

[kristiankynk]

Brand new full battery, brand new connections. Would fuel starvation occur exactly from 3000rpm?
I’ll check the fuel lines. What is VST?

[Murray]

Vapour Separator Tank replaces carburetor. Probably not, 3000 RPM is Suzuki’s rev limiter for faults. From my service manual Low oil pressure will drop revs to 1000 RPM, not your issue. Overheating and Overrevs will drop RPM to 3000RPM. When you turn the key to on(not start) does the tach do it’s self check? Have you checked the new connections, maybe one is not 100%? Any chance you bumped a connection to a sensor, it might look fine but it isn’t making 100% contact all the time? Neutral safety switch seems to be a popular suggestion, I’d start there.