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

[N2 Fishing]

Parts finally arrived for lower unit with 2 thermostats and Starboard side heat sensor. Installed all the parts and going to go for a test drive today. All the rear bushing in the lower unit are there. I also replaced the cracked bushing that I previously glued together.

Does anyone know know if there is a 3/8” barbed check valve for fuel line that I can install before the primer bulb?

[N2 Fishing]

Found a 3/8 barbed fuel check valve and ordered it from Amazon. Should be here by tomorrow.

[Moonlighter]

Found a 3/8 barbed fuel check valve and ordered it from Amazon. Should be here by tomorrow.

Why would you want to put an anti-syphon valve in the fuel line when it is not needed?

Allthey are is another potential/likely source of problems IMO.

[N2 Fishing]

If the check valves are not working in the primer bulb then this way I can keep the gas from flowing back into the tank and keep the fuel line primed as it should be.

[N2 Fishing]

Mostly I am going to be using it as a tool to help with solving a problem. Basically a cheaper alternative to the cost of a new primer bulb.

[N2 Fishing]

Ok I just finished checking the vapor separator visually and blowing into the fuel inlet with my mouth to see if I could blow any air past the needle valve. I could not. The vapor separator looks good inside the bowl area also. I don't think the separator is an issue.

I took the boat out last Saturday and it ran good for the 1st half of the day then it started acting up again later in the day and bogging and acting like it was stopping or locking up then going again. Also We all could smell raw fuel very much from the time we came to an idle from the very first on plane after launching the boat.

Q #1: Can any one tell me if the 4 brass/copper nipples that look like they are suppose to have a hose connected to them at the the base of the block in these pictures below is normal or is there suppose to be something connected to them?

Q #2: Next question: two of the low psi fuel pump fuel lines are orange. Is this normal or were they replaced?

Q #3: Last question on the top of the vapor separator there is a little rubber hose that is sitting on the inside of the hose that is connected to the separator. Is that normal?

[TommyDee51]

I have 2016 Suzuki DF200A four stroke. Was working and cooling just fine all summer. I tried flushing with "Saltaway" for the first time and it foamed up nice and stayed cool. I then changed the oil and filter and the lower unit fluid and the five anodes in the engine. I then flushed again and the engine now overheats every time and no water comes out the pee hole. Has anyone experienced this? I was going to start with impeller, then thermostat but just wanted to know if you boaters have any experience with this or can guess what happened. Thank You, Tom

[Harper]

TommmyDees51, it would be best if you would start your own thread instead of posting on this old thread concerning an entirely different engine.

Just go to the top of the forum page left side and click on the blue "+ New Topic" button to start your own thread.

[N2 Fishing]

Ok the over heat alarm is still a thing. I have another issue that is concerning me. On a cold start after priming the fuel line I get raw fuel dripping out of the bottom exhaust port through the prop with a lot of smoke. I did not have a water line with dog ears hooked up so it made it easy to see the raw fuel pouring out of the prop.

Does this sound like fuel injector issue or something else. I have smelled raw fuel several times while out on the water.

[artdf175]

I have gone back through the thread
first I am not all that versed on DT engines
however I was thinking DT were 2 cycle carberator engines??
this sounds like 4 cycle DF model high pressure fuel pump fuel injectors as I have a DF175 4-stroke
but that aside
is it required to pump the fuel every time you have a cold start?
I never touch mine.
if you are getting that much fuel out the exhaust it would indicate to me a fuel float problem
with a high pressure system or the float is located in the top of the vapor separator housing. If you have had that apart go back in and double check assembly. putting a little air pressure on the 'in' fuel hose side can tell if the float is properly adjusted andis closing off as it should. if not shutting off correctly might also spill gas someplace else that you are smelling when running.

when was the last time you replaced the water pump? your thread started in 2019. Every year is not too often . make sure you check all the gaskets that feed water up to the top. one that is broken/damaged or missing and you will not get enough water flowing to cool the engine properly
Art

[N2 Fishing]

Water pump was replaced spring 2019 with added water psi gauge to watch that, new fuel line from tank to new Yamaha screw on water filter/water separator and new fuel line from that to the primer bulb and new line from primer bulb to inside the cowling. Have to look back at this in a bit. Brother died last Saturday and we are trying to get him buried. Will start a thread to provide a go fund me link for any gracious people who can help.

[Solarman]

N2, sorry to hear about your brother. Prayers to your family.

Generally with carbs to much fuel in cylinders is caused by the float needle valves of one or more of the carbs being set too high, allowing an over flow of fuel getting into the throat of the carbs. This tends to flood that carbs cylinder. On fuel injection systems that fuel balance is controlled by the TVS (throttle valve sensor) and the fuel pressure regulator, this regulator sends excess fuel pressure back to the VST. The TVS is controlled by the computer and the gear counting coil (counts the teeth of the flywheel), which also involves the timing of the motor, related to the gear counting coil and position of the TVS.

So, each of these items should be tested per the Suzuki service manual to find out which is not in spec?

As far as the over temp, I have mentioned to many about the sub- water cooling system below the water pump assy that can cause over heating because of loose grommets, this allows exhaust pressure to interfere with the water pump picking up the water needed to cool the motor. Usually the higher the rpms the faster it overheats?

You have a temp gun, and indicated one side of the block was heating up faster than the other, this could relate to blockages in the water channels?

But if you do have any blockages in the water channels it could cause overheating. Running a good flushing solution in a large container (I used 4 or 5 gallons of vinegar) for a good couple hours total time, with cooling periods and adding makeup water w/vinegar as needed.

This thread started a long time ago?

Good luck, post back on what you find out.

[N2 Fishing]

Thank you Solarman for the kind thoughts and prayers, God bless.

When I get more free time I will get back to looking into the suggestions you mentioned with the TVS, fuel psi regulator and VST. It’ll start and idle high while cold and idle down when warm. However at this point I don’t think I should run it anymore until this raw fuel issue is properly diagnosed and corrected. I think the over heat alarm may be related to a broken head bolt I discovered. I’ll have to look into the manual to see if I can determine the timing.

[Solarman]

N2, it should run a little higher when cold, that's normal. The timing is controlled by the compete and other items I mentioned. The only way to get too much fuel is as I mentioned earlier. You might find someone in your area that can test, check, and clean your injectors? Check the VST float setting. If the setting is too low, your motor may act like it's running out of fuel. If the setting is too high, fuel will keep trying to fill the VST and not shut off.

Good luck, post back on what you find out.

[N2 Fishing]

Ok I'm finally getting back around to this raw fuel flooding issue. I have pulled the injection system from the fuel vapor separator and all componamts to bench test. I want to see the injectors not leaking while under pressure, the regulator not leaking from the diaphragm through the vacuum line and recheck the vapor separator to make sure it does not have any float or needle and seat issues.

I still need to look and find how to check for the Throttle Valve Sensor issue.

I just reread your last two post Solorman and need to look into an exhaust leak below the pump as well but it typically will overheat at idle or slightly over idle while under a load in gear.

Hopefully I have not done any irreversible internal damage up to this point and will be able to find fix and solve the problems. Compression readings while cold were between 100 to 105 psi on all cylinders.