DT 115S Fuel System Routing

I recently had a fuel issue with my 1999 Suzuki DT 155S which caused me to do a diagnosis from the tank to the throttle body. Turned out it was a check valve at the tank so easily enough solved. My issue is there are two identically sized hoses connected to the throttle body, one that runs mixed fuel from the fuel pressure regulator and one that connects to the top of the fuel vapor separator (for vapor I believe). I did not pay enough attention when disconnecting the two from the throttle body to be sure which is which when re-connecting. The throttle body has the positions labeled P and A but I cannot find anywhere those are defined.

I connected the hoses in what I thought were the correct locations and the engine runs. Sadly I switched the hoses and the engine also runs. I have not run it at speed or under load with either hose configuration.

All help appreciated!

Selffixer.com has an service manual for your engine(pdf) for $11.95. If no one has an answer for you I’d suggest get a service manual.

Appreciate the information on the manual. I did find a Workshop Service Manual online (https://issuu.com/glsense/docs/suzuki_outboards_workshop_manual) that covered a lot of years and models. Unfortunately it did not have the detail to solve my issue, perhaps a more specific one would. Hopefully there is someone out there with a similar engine that can confirm with a quick look.

Thanks again

I don’t think the manual you are referring to is a genuine Suzuki service manual. My manual doesn’t have the first chapter that deals with boating safety and my manual has a different layout. That being said my manual is 10 years newer than what you are looking for.