'1999 Suzuki DT 115 hp dies at idle

I have just bought a Suzuki DT 115 EFI that dies whenever you shift it into nuetral. At high idle speed and above it runs perfect. No issues at all at anything above low idle speed. As soon as I shift it into nuetral it dies. It will restart right away and if I do not bump up the throttle a bit immediatly it dies again. Like I say, other than that it runs great from say 1200 rpms on up.

Any ideas?

Re: '99 Suzuki DT 115 dies at idle

A little more info...

I replaced all the fuel lines on the motor and on the boat from fuel tank to the motor. I have a water seperator fuel filter that I put in. New primer bulb, etc. I replaced all the fuel lines because some of them started feeling soft. I replaced the little fuel filter on the motor.

So I changed all that out and ran it again today. It runs fine the majority of the time but still dies in neutral. Anything over 1k rpms and it runs OK. At say 1k rpms to 3k rpms the motor sputters once in awhile. That is the sputter where it dies at idle.

A few times today it idled at neutral with no problem. Maybe 2-3 min straight without a problem. Other times it dies as soon as I pull it back to neutral or will run 10-20 seconds at nuetral and as soon as the motor sputters it dies.

I ran it about 40-50 miles today and it did great except for the sputter and die in neutral. I hope someone has some ideas. I am sure it is minor and I hate to put the dang thing in the shop when I know it has to be something simple.

Re: '99 Suzuki DT 115 dies at idle

Flipping through the manual I didn't see anything jump out but it gave me a few ideas.

It could be the throttle linkage adjustment, it is supposed to be 197 mm. There are detailed instruction in the control cable and linkage adjustment section. There is also a throttle stop screw, it could have fallen out or have moved. Possibly the throttle valve sensor is going bad. Maybe an air leak in the fuel hose system that cant be overcome at low rpms.

I hope my rambling helps in some way.

Re: '99 Suzuki DT 115 dies at idle

It sure does. It is going right along the things I have thought of that might be causing it.

My first thought was an air leak in the fuel lines somewhere but like I said, I have now changed all of those out and still have the issue. The guy who owned the boat before me told me it happened from time to time with him as well. He thought it was a check valve on the fuel tank's pickup. Well, I took it apart and it isn't a check valve, just a 90 degree fitting with the pickup tube coming out the bottom and a hose barb that screws into it for the hose to clamp onto. Plus, there is enough fuel in the line, filter, etc that if it was an air leak at the fuel tank it ought not die immediatly after pulling it into neutral.

Second thing I thought was maybe it is choking off the air. From what I can see nothing has worked loose. That doesn't mean it isn't out of adjustment. I just don't know what would be right without a manual.

Third I thought maybe a sensor of some sort but I am new to this motor and don't know what all sensors it has or which ones can cause this.

I gotta get one of those manuals.

Other than this one little issue it is a great running motor. Very good low end and runs strong. It is just bugging me.

Re: '99 Suzuki DT 115 dies at idle

I purchased my manual from Browns Point Marine for $60. You can check eBay and other places for a slightly better deal.

Your problem is tough. It will take a good bit of troubleshooting.