Re: Testing Low Oil Sensor on Honda GX Engine

[scott]

My generator with a Honda GX270 engine suddenly stopped running. My
first thought was that it was low on oil. I checked it and it seemed
to be within the acceptable level but filled it to full. Didn't help.

I took out the spark plug and grounded it and the spark looked weak
and intermittant. I tried switching the ON/OFF switch a few times and
jiggled the wires but no noticeable improvement. I checked to see if
anything was grounding out but could find nothing. I tried
disconnecting the wires to the ON/OFF switch and the low oil sensor
but no luck.

There is a small (1 inch square) metal box that is connected to the
ON/OFF switch and the low oil sensor. Is this the electronic ignition
module? I looked in my Hayne's Small Engine Repair manual but it
didn't show such a thing. It also mentioned the existance of low oil
sensors but had no info for the Honda engines. The owner's manual
that came with the engine doesn't even suggest checking the oil if the
engine won't start!

Is there a way to test the low oil sensor or bypass it temporarily to
check it? Is there a way to test the ignition module? The ignition
coil does not appear to be damaged in any way and is not loose or
obviously out of adjustment but I'm going to try to check it with an
ohmmeter.

The engine was running normally and suddenly stopped. I started it
again and it ran for a few minutes and then suddenly stopped again.
It acts like it has a loose connection or something but I can't find
any.

Any suggestions?

Thanks.

Hi,
The small metal box is a signal conditioner for the shutoff sensor in the
crankcase, it is probably just a scr that once is triggered, latches to
make sure that the engine dies and also lowers the load on the reed switch
in the sensor so it won't be damaged when vibration causes the switch to
repeatedly open and close, damaging it and causing loss of protection. I
work in a mower shop, we used to see reel type mowers that the customer
told us would cut out at each turn for weeks as the switch was repeatedly
triggered by slosh .Later on, this was the engine that died from lack of
oil when the sensor failed.
To test the ignition separately from the sensor and all other parts, just
disconnect the small gauge wire from the coil that hooks to the stop switch
and the sensor. It is very simple, they just ground the ignition primary
(small) wire to kill the engine.
You are probably just seeing normal operation when oil gets low. When
the engine starts, oil is sprayed by the oil slinger all through the
engine, and what is om the crankcase walls lowers the level a small amount,
shutting off the engine. Engine dies, oil runs back to bottom. switch
opens, and it will restart.
Full oil level is top of the threads, about to run out. I havbe seen
engines that will die at three threads below full (threads inside the oil
fill hole).
Proper spark should be white or blue when viewed indoors as in a garage
out of direct sun, and should jump at least a 3/8" gap- take a old plug, cu
off the ground electrode and you have a tester, the spark should jump from
the center electrode to the outside and you should be even able to hear a
good strong spark. Weak, erratic and yellow colored spark indicates a
problem.
Good luck
Scott