Suzuki dt65 no spark

[Sniper_swe]

Hi!
I have a dt65 with no spark unless i unplug the oil warning unit from the cdi box. Does anybody know why?
Engine starts right up with the unit unplugged. As far as i know the unit is only supposed to warn and put the engine in failsafe. Are there any way to measure the warning unit to see if it is broken?

[Solarman]

First off, it is helpful you include a year when asking questions on a motor. The fact that it's a "dt"65 helps a bit. That being said, your motor is roughly 15+ years old, and it is possible that the oil sending unit may have been a flow switch that indicated "low" flow, and "no" flow. Then newer motors added the heat sensor to a water flow sensor, and oil flow sensor, so if either flow sensor and heat sensor acted up together it could shut the engine down until repaired.

I would not run the motor if there is a chance of low, or no oil flow, as this could cause serious problems, run pre-mix if any chance the sensors are right. And until you know oil is flowing again. It may be possible to clean the flow switch?

So it is possible that you could lose spark.

The only suggestion on checking, is to check those sensors per your year service manual.

Good luck.

[Sniper_swe]

Thanks for your reply!
the engine is from 1990 from what i can tell. It has a oil flow sensor and a cooling water sensor on the cylinder head. The cooling water sensor only has one cable that is grounded. It is a green cable. Maybe this sensor is broken because from what i can tell from the electric diagram is that it should have two cables. One ground and one going to oil warning unit?
can I bridge this sensor on the oil warning unit somehow?

[Solarman]

I don't have the electric diagram, or the manual for your motor, so i cannot tell what might work. It may be that early (1990), they only wired those two sensor/flow switch in series? Then the flow switch for oil would only be an off, or on switch, showing continuity, not multi stage resistance. Therefore the heat sensor may be a simple thermister that varies the voltage being sent to it, as long as the flow switch has continuity through it?
Your service manual should give you a way to test each sensor/flow switch with an ohm meter.

Good luck.

[welshspringer]

Seeing that this post is dealing with a DT65 I am hoping I can piggy back. I have a 1995 suzuki 65 hp which has had (due to ill health) a 3 year period of non use apart from running in a tank.
I started the motor for the first time in several months (8) without changing the fuel. It started after a little while, ran for some 2 - 3 minutes and died.It has kept dying since. At a loss or prescribe the problem. HELP NEEDED.

[Solarman]

Welshspringer, it is always best to start your own post, as we can deal with yours directly with you. It is most difficult to discuss one problem, much less two at the same time.
thanks.