Suzuki DT85 engine problems

[michalgouws]

Hi all i have a DT85 2 stroke, it runs well when on idle or 50% throttle once i run at 100% it runs very well and after a while it losses power and sounds like it only runs on 2 cylinders the buzzer comes on and a red light burns on the engine can it be oil starvation or overheating? The oil is filled to the max and the tell tail sprays a very strong stream of water. Any advise on what to check that might be causing the problem. Once the problem starts and i take it back to idle after a while i can go flat out again and then it happens again.

[artdf175]

I am not sure if your model has a rev limiter that would limit rpm in an overheat situation
When was the last time you serviced the water pump?
The pee stream is not necessarily a complete indicator the engine is getting enough water to the head to keep it cool
Might look at the thermostat
Art

[michalgouws]

Thank You artdf175 i will check the thermostat today if its not the problem will look at water pump i assume if i remove the thermostat and there is ample water that the water pump is still fine or would you recommend that i remove and do inspection

[Solarman]

When going wot does tell tale stream slow down, sputter, or stop/ turn to steam when the buzzer and light go on? This symptom could tell us another story, or indicate a different problem.

If the tell-tale is strong and steady through wot then it does sound like thermostat not opening all the way. But it can also be blockage in water flow around cylinders caused by corrosion building up in water pas-sages. If you have a laser temp gun (about $35 harbor freight), you can run motor on muffs and check temps around cylinders to see where temps are running highest, if temps are highest around thermostat then I would pull it. Any other areas might indicate a need to run vinegar (or other corrosion flush) through motor.

Pay close attention to the level of oil used in your motor at all times. If motor overheats from lack of oil there is a serious problem.

Good luck, post back when able to let us know how it's going.

[michalgouws]

Hi all i removed to thermostat housing and the thermostat was already removed, i started the motor with the muffs on with the housing removed the water flow squirted out looks like 50% water 50% air mixture when i increased the revs the water would drop down and then spray out again the water is not constant, i removed the water pump but the impeller was still intact. When the motor is running there is no water coming out at the exhaust port in the leg, i the force water with hose in at the top then you can hear the engine filling with water and then exits at the port. I removed the oil tank while it was running and saw that the oil in the pipe is being used and also smoke when cold en smoke decrease as engine heats up. I assume that the impeller is faulty, i have ordered a new one and give feedback if it solves the problem.

The pee stream has a very strong constant flow of water from start all the way

Since there is no water at the exhaust port could this be blockage or just the impeller not providing enough water?

[Solarman]

If thermostat is out and you didn't take it out, there is a chance previous owner had problems overheating like you're having. If you're replacing the impeller, then might as well replace the housing for the impeller. This will eliminate the chance the housing is worn, and causing problems. You should also install a new thermostat.

Also, before you put the lower unit back on, look at the surfaces that go together, if there is deterioration from corrosion in the mating surfaces, take some pics and post them here before you put it together. And let us know.

After doing the above, if motor is still overheating, then you can still use the laser temp gun, and check what areas get the hottest first, as mentioned in my other post.

Good luck, post back when able to let us know how it's going, or what you find.

[michalgouws]

I fitted new impeller and forced water with hose through every possible hole and looks like the impeller was on its way out and a blockage inside somewhere but all is good now. Thx a lot for all the assistance.

[Gremlin68]

I’m having the same dramas