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1996 DT150S Overheat buzzer and light problem at low speed and idle.

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  • #76
    many of the manuals cover more than one engine model
    in fact when you search, for example your water pump
    you will see it will covers multilple HP models Suzuki DT 150STCLT Beginning VIN# 15002-651001 WATER PUMP (DT150/175/200/150EFI/200EFI ~MODEL:97)

    good luck Art


    • #77
      I just checked the low psi pumps and they do not appear to be leaking through the back. Although one of them "the bottom one" looked like it had some crud "small specks of something" inside that pulsation port. Think I'll buy a couple of rebuild kits and rebuild them now while I can still get the parts.

      Next thing is to clean out a ride mower gas tank to use as a gravity feed tank to hook up to the VST. Then I'll get it set up so it sits above the VST on a bench and hook up the rest of the high psi injecting system with the exit line from the pressure regulator dumping back up into the fuel tank.

      If the injectors are not leaking then I'm out of ideas other than having the EFI checked out to see if it is keeping an injector open when it's not suppose to.


      • #78
        Hey I have a question for when I have the fuel system all put back together and am ready to conduct the oil flow tests with oil pump valve fully closed and fully open at 1500 RPM.

        Should the oil pump linkage rod be disconnected to allow the oil pump valve to be fully closed and fully open while running the engine RPM’s at 1500 RPM?

        I can’t post pictures because of the 2mb file size limit so perhaps links to another forum when I can share pics can help.
        Last edited by N2 Fishing; 02-11-2024, 03:54 AM.


        • #79
          I made a quick vid for how I have the fuel system set up for testing and am making some progress on the Suzuki DT150S Fuel system.


          • #80
            N2 you need to focus on one problem at a time.

            Your first problem seemed to be overheating at low rpms? Generally I have found blockages in the passages that cause low rpm overheating. You should run Salt-Away/vinegar/ or other corrosion flush solution in a clean tub (after you are sure your water pump is replaced/ repaired/ installed properly). Run the motor in the same solution for about 2 hrs total (about 15-20 mins at a time- or until solution is too hot - let cool, then run the cycle again). At the same time use the temp gun and record the temp readings at different areas of the powerhead. Try to locate where it's getting the hottest. Each time you run the 20 min cycle record the temps at same locations to see if they're cooling down. You can run the same solution in the same tub adding a little make-up water and solution as needed just to keep solution above the waterpump.

            Once done flushing motor then focus on fuel leak. If pumping bulb fills the filter on motor then look closely for any signs of fuel leaks, keeping pressure on bulb. Generally the only time air gets back into that filter on the motor is when there is a leak in the fuel system somewhere? Keeping pressure on the bulb will usually show fuel dripping where there is a leak.

            Yes fuel and air can leak at the low-pressure fuel pumps, and yes there are little check-valves in each LP pump, these check-valves do NOT come in rebuild kits, only with new pumps. Yes you can take LP pumps apart (carefully) and put them back together if not damaged. Yes, the rebuild kits have diaphragms and gaskets (but NO check-valves). Do not use any sealants/glue/epoxy when putting back together. If the check-valves are cracked/broken/missing they are probably lodged on the back-side of the needle valve seat, and could be restricting fuel flow going into the VST?
            If the float bowl setting is too high it will over-flow into the motor or out the air-intake on the VST.

            Your HP rail and fuel system seem to be fine with the pressure you're getting. As long as the injectors are not leaking or blocked up i think they're fine.

            Your oil system does not go to Each cylinder as similar motors do. I believe your oil system feeds directly into the VST. Let me know if not?

            Many motors use the same parts your motor has and you might see some fittings that are unused, brass nipples that are blank?

            Put you motor back together and let us know what is going on after.

            This thread is much too old. Let's get this worked out.

            Good luck, post back on what you find out.


            • #81
              Thank you Solarman. I can confirm the Injectors do not seem to leak at all and all seem to have a decent atomizing spray pattern with some better than others.

              I purchased some Berryman B12 Chemtool Fuel Injector Cleaner to use on a test bench with an electric pulsing injector cleaner tool. I also have some Seafoam but have heard mixed reviews on that stuff. I have not used any injector cleaners as of yet. Don't fix if it ain't broken kind of thing.

              After 5 minutes of rest from being pressurized I can also confirm the HP fuel system holds steady pressure of 32 psi with the injectors in the injector rail. This is well above the 28+ psi service limit specified in the manual.

              Now to put the bench test system on the motor with the injectors in the rail but not in the engine to see if the EFI system is causing any of the injectors to stay open. I hope not.

              I wanted to rule out any major internal fuel leak prior to starting and running the engine anymore to prevent further damage if there is already any from excessive fuel.. Hydro lock is one of my higgest concerns.

              Yes the overheating alarm is the main reason I started this help toppic and agree it's been dragging on for way too long. I appreciate all the advice and knowldge shared so far


              • #82
                N2, while you have your fuel system & VST off the motor it might be a good time to inspect (carefully-by the service manual) the reed valves, to see if any are bent or broken? Just a thought.

                Good luck, post back on what you find.
                Last edited by Solarman; 02-14-2024, 11:03 AM.


                • #83
                  Originally posted by Solarman View Post
                  N2, while you have your fuel system & VST off the motor it might be a good time to inspect (carefully-by the service manual) the reed valves, to see if any are bent or broken? Just a thought.

                  Good luck, post back on what you find.
                  Could this be done with a camera through the intake throttle body or does the intake plenum have to come off to visually inspect the reeds?


                  • #84
                    Just spent an hour reading up on the thread linked below related to a '95 dt150 that would not rev past 2000rpm. I was hoping for a good ending. :/ Some good info in that thread. I might need help with testing and reading for the TVs sensor once I get to that point. Solarman you mentioned that as a possible problem.



                    • #85
                      This was Tuesday evening seeing how the spray pattern is working with the injectors hooked up to the boat.



                      • #86
                        I put it all back together, primed the fuel system and started finding one leak after another at pretty much all the fuel hose junctions

                        I'd fix one leak by replacing the hose to find a new leak at a new hose junction.

                        Bottom line is I need to replace all the fuel hoses under the cowling.

                        I also pulled the lower unit and put the water pump parts back as they should be with the gasket under the bottom of the lower impeller plate. One less reason for it to overheat.
                        Last edited by N2 Fishing; 02-15-2024, 11:59 PM.


                        • #87


                          • #88
                            Re post #87, could be the clamp? Quick check would be to slide the clamp down and try a gear clamp in its place.


                            • #89
                              Clamp could be old but the hoses are soft and old so I’m just going to replace all the hoses and go from there. I shortened a couple and reclamped them to solve those leaks at the fittings.


                              • #90
                                This video shows I still have an issue with flodding through the VST with fuel coming out at the throttle body.

                                Is it possible to pump the primer bulb too much and cause issues with the float tab that pushes up against the needle. Wondering if over priming the pump could have bent the tab on the float?

                                Last edited by N2 Fishing; 02-16-2024, 06:02 PM.