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oil light came on?

4093 Views 34 Replies 11 Participants Last post by  inspectorudy
My 420 the oil light came on but I have checked it and it seems to be fine. What is causing this light? I did just install the belly pan..... Can I still mow with it? Should I stop using it untill I figure out what is wrong??

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check the wire coming from the oil sender that it is still on tight or not broken.
from my experience this system used a NORMAL CLOSED
oil pressure switch.
the closed position allowed the light to come on because it
was grounded.
once a certain pressure was reached the light would go out,
because the switch opened up.( no ground )
if you have a multimeter, test the switch not running.
it should ring ( speaker symbol ) when you go from the terminal to ground.
then start the engine, and at idle it should not ring.
hopefully you only have a bad switch.
thank you. boomer ( the used onan engine parts guy )
My 420 oil light would come on at idle, so I wouldn't let it idle , two years later the onan grenaded
was there any oil left in the pan
when that happened?
I always checked and added oil before using, Onan never did smoke, then 15 minutes into cutting BOOM. then most of oil was all aver the tractor and my yard
Burned: so were the two related ? I'll investigate further and see what I can come up with.

Side note: I like how you took care of your "POP". It has me thinking, I really need to also.

thanks for the wise words.
I found the problem, seems the wire to the sending unit got severed somehow. I replaced it and magically the light now is not on.

Thanks for all the input guys it is so much appreciated!
the previous owner was more concerned with a clean tractor, it was spotless clean, when I called him and asked when was the last time hydo fluid was changed, he said "hydo oil??" onan needed an over haul, bearing were worn, I could rock the crank with my hand, no wonder it had no oil psi at idle, glad your was just a wiring issue. two days after that day is when I bought my X720 and sold the 420 "as is"
well I have to keep the 420, I just can't swing or justify spending that kind of money on a tractor.
I have looked all over my T260 Onan and cannot find an oil pressure sender. Does anyone know where it might be? I looked inside the tin over the filter but there isn't anything in that spot.
I have looked all over my T260 Onan and cannot find an oil pressure sender. Does anyone know where it might be? I looked inside the tin over the filter but there isn't anything in that spot.
By the oil filter,deep inside.
well I have to keep the 420, I just can't swing or justify spending that kind of money on a tractor.
Every since you got the new tractor I thought you sent the 420 down the road,glad you kept it.???

boomers_influence would know if the T260 ever came in a John Deere LGT, and he would be able to tell you what it was equipped with from the full engine model # and serial number. But take a set of photos of the area around the oil filter, with special attention to the oil filter mounting plate/bracket. That would show if there is a port/tap for a oil pressure switch. Then we can find out if it is easy to add just a switch or you need a plate, gasket, switch. Is the wire still there for the 420 oil dash light?
Russ, my problem is that this 420 is a Frankenstein. It has the wiring harness of a B43G engine but now has the T260, Performer 24 engine in it. It ran when I bought it so I did not do a close examination of all the little details. It does not have a VR hooked up on it. I discovered that when taking things off of it. Above the oil filter on the bracket, there is a cap screw and just below that some sort of indentation but no threaded hole. I have no idea what this engine was doing before it landed in this tractor but I do not think it was on a tractor. I figure probably a generator. The solenoid is a standard type that was popular years ago but is still available. The wires to the coil are all spliced and miscolored. I do have a used P218 harness that seems to be intact. Any advice would be a help. Now I know why I quit buying and selling 318's! I'll add 420's to that list next. But God! What a beast!
Yeah, B43G harness okay, is this the tractor harness or the engine harness (from the module plug point of view). If it is for the tractor, I'm going to need more pics. Your need to find some proper gauge and colored wire (stranded, oil gas resistant coat) to get thinks correct, or replace the harness with the P218 harness. Yeah, the T260 most likely came from a generator/welding setup. Do you hook up a charger (to charge the battery) so the PTO can function?

the T-260 and P 224 are DIFFERENT engines.

the T-260 is the only Onan 60" CID twin that has the dipstick tube,
next to the oil filter.

a bunch of GOOD pics would help.

thank you. boomer ( the use onan engine parts guy, also NOS and new )
Found a SM for the T260

Here is the link:

engine information
Ok, I went down to the basement and took these pics. There is an Allen plug where the oil pressure sender goes. I couldn't tell before because of so much gunk. That VR is one I had and was not connected to anything when I got it. I found the stator wires coming out by the coil from where the oil plug was. It has a remote 12 solenoid that is mounted in the tower. The oil dipstick has no upper support nor is there any place to add one. The gasket around the oil pan and the block is rubber and is hanging over all the way around the block. The carb is a newer one and the governor is not of the dashpot type.There is a number on the block if that will help anyone determine what this thing is. Boomer, can you tell me the model number for the oil sender? Thanks to all of you for helping. BTW, the funny thing is that it runs great!


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