87 DT115 Stalls after 15 seconds

[goinginsane]

I have an 87 DT115 giving me issues. It will start and run for 15 seconds they sputter and die.
Rebuilt all carbs.
Changed fuel lines from tank to motor.
Rebuilt fuel pump.
Emptied all fuel and refilled.
Checked compression and has 115psi on all cylinders.
Will restart every time but does the same thing - 15 seconds and dies. It doesn't matter if you increase throttle or leave it at idle it does the same thing each time.

My thought is a timing issue but as its all controlled by the CDI I'm not sure if there is even a way to adjust it.

Any thoughts or people who have seen this before?

[Solarman]

87 dt115, sputters then dies

Ok, you did rebuild fuel pumps, and rebuilt carbs?
When you rebuilt fuel pump did you notice the small check-valves in the base? Generally these fall apart and start blocking fuel to carbs. These ck-valves operate with positive and negative pressure in the block, in-turn this causes your fuel pump diaphragm to work.

When you rebuilt carbs, did you soak the carbs well? Did you use air pressure to blow through passages? Lines? What did you set the low-speed jets at (# turns)?
Let us know. Do you have a good shop manual for your dt115?

[goinginsane]

87 DT115 Stalls after 15 seconds

Check valves were good in the pump.
Pump seems to be working. When it starts I can increase throttle normally. Just dies after the 15 seconds.
Soaked the carbs, blew out all the passages, and changed the needle valve and seat.
When I changed the lines to the tank I also checked the vent line to make sure that wasn't blocked.
I set the screws at 1 1/2 out like the manual says for base setting.

[Solarman]

dt 115, '87, runs then dies

Ok, if carbs and fuel pump are well then have to check all electrical next.
You should have one gear counting coil on back of flywheel. Check that it is proper distance to (distance is critical here, too far and skips teeth, too close gets damaged) teeth on flywheel. Also, check the reading of it by the manual.
If gear counting coil is good, then need to pull flywheel and run checks on all the pulse coils by the magneto, and need to check everything there. The gear counting coil together with the pulse coils and magneto charging coils give your engine its timing. There is a section in your manual on them and how to check. Inspect flywheel magnets, if epoxy is cracked or magnets are loose at all it will need replacing.

[goinginsane]

1987 DT 115 stalls after 15 seconds

So I tested all the timing coils according to manual. Resistance was good on all. Tested the throttle sensor, also good. Everything pointing to CDI so found a known good one to try out. Did the same thing ( 87 suzuki Dt140 CDI for sale ).
So now for the wierd. Started it a couple times with the new cdi and something odd happened.
Motor sputtered, reved then dropped down, then idled fine and continued running and didnt stall.
Problem is there was no longer a water stream coming out of the motor so I shut it down. Figuring I have no water pressure?
Waited a few minutes, started back up fine, idles fine but still no water stream.
Im assuming the water should have a stream out that port at all times when running?
And what in the water system would keep the engine from running?

[Solarman]

running issues, now no water

Motor should always have water out of the pee hole anytime it's running. You can not even bump the motor over without water on the impeller. If the impeller is dry when turned it will fragment in seconds.
If you have had water on the impeller everytime it's turned over, then try sliding a small wire up the pee hole to see if something is blocking the flow.
If you haven't changed your impeller in the past couple years, maybe it has been weak and just gave out?
The only way I can see water causing the motor to run bad is if overheating, but the monitor should indicate overheating, and may throw in limp mode.
Anyway, maybe in disconnecting and reconnecting some of the wires during testing of the coils or other items caused it to reconnect and start sending a better signal to the ecm? Not sure what happened, but fix the water problem and see if it's running for real now. And let us know... There still could be an intermittent electrical problem that you'll have to find. If that's the case, you may be on the road to solving your problem.

[goinginsane]

Suzuki Dt115 stalls after 15 seconds

So pulled the bottom end because I was thinking impellor went but everything looked good. Wasn't even thinking of a plugged hole. Snapped a bolt on the water pump housing so fixing that while waiting on parts to change the impellor because might as well while i'm there. I'll update after I put it together and see what the deal is.

[Solarman]

no water from pee hole

That's kind of why I suggested trying to slide a wire in the pee hole, it is possible a small piece of corrosion came loose and blocked it. Good luck. Will wait to hear back from you.

[goinginsane]

87 DT115 Stalls after 15 seconds

So put it all back together and i'm back to the same problem. Starts and runs for 15 sec. then dies.
I have a water stream back now so that's good but that doesn't help with the initial issue.
This thing is confusing the hell out of me.

[Solarman]

back to running issues

Ok, runs 15 secs then dies.
You have no code light flashing on the monitor, right?
Have you a timing light that clips onto the plug wires? If so, clip to various plug wires and test if it quits firing on all cylinders when it dies?
You can also go back through the plug connectors testing the different coils, and sensors to see if all read good still. There could be a bad plug connector on one of the wires/ components sending a signal to the ecm. But it helps to know if all, cylinders die at once, or just which ones act up? If electrical at all?
Keep us posted.