JD 318, no idiot light????

[Arkie]

1983 area B43 onan on a JD 318
Ser number of tractor and engine model
Product Identification number MO318X234837 (appears to be about a 1983 year model)
Engine is a Onan B43G/GA018

low oil pressure Idiot light on dash don't come on when key is on. bulb is good.
All other lamps operating ok.

Where is the oil pressure sender located?
The engine has all the air cowling in place, cannot see the engine block because of the air cowlings and I can only see the very top of the oil filter.
Thinking maybe if I can find the oil pressure sensor I can maybe ground the wire and see if the idiot lamp comes on.

I also need a link to download and print a wiring diagram for this dog??

[KE4AVB]

If it was a snake it would have bitten you by now. Item B. No kidding I done pulled out one snake this year already.


Wiring Schematic (Can provide more detailed diagrams from service manual if needed).

[Skywatcher]

Hi Arkie

Part number for oil pressure switch is HE309-0546 which I believe is a 1.0 Bar (15 psi) switch ⅛" NPT. However, before you take the switch out, unplug the wire an short to ground with key on. If oil light does not come on, you have a broken wire or loose connection. If light does come on, you have an open switch, so replace it.

I had the opposite problem with a 1974 Honda CB-550-Four quite a few years ago. The oil pressure light would not go out unless I disconnected the switch wire. Connected a pressure gauge to switch port, 60 psi @ 5,000 RPM and 20 psi @ idle. Original switch was a 0.5 bar (7.5 psi) so installed a 1.0 bar pressure switch and the oil pressure light went out. I did however find that the light would just flicker at idle when the engine was hot. This told me that the oil pressure was @ 15 psi or double minimum pressure, blip the throttle and the oil light would go out. All the best,

Sky

[38racing]

I had an 86 chev s10 v6. Oil pressure gauge would read normal at startup. After warmup the needle would slam to max. Now I have a 2002. Needle reads normal at startup. After warmup it reads low to the point of the check gauges light coming on at idle on real hot days. Been like this for years. I had lower intake gasket replaced years ago and never thought to replace the sensor while the distributor was out.

[Arkie]

KE4AVB

Thanks for the wiring diagram: I tried to blow it up and print, but it get fuzzy when viewing.
I can make out the oil idiot light wiring colors enough to trace it.
I got this JD non running and I can see where it's been worked on and butchered up over the years, wiring cut and spliced, ignition was bad, carb clogged, exhaust pipes broken due to vib's from the engine mounting bolts loose and couple gone, engine has been out, severe nasty oily dirt everywhere wiring cut and butchered. I've got it running, mowing and driving good, and I'm lucky that the oil light is not staying on instead of staying off, right now.
I cannot even see the block behind the oil filter or oil sensor due to wrap around metal air cowling (yes, might be a bunch of venom type snakes that bite behind that cowling) and the cowling looks to be bolted down by the frame underneath, may have to raise the engine to get the air cowlings loose. The oil sensor wire may not even be connected or wire may be cut somewhere or sensor may be gone and the hole plugged. I'm going to try grounding the sensor wire before it gets to the engine connector or before it's not visible behind the air cowlings.
Did not want to pull the air cowlings and get snake bit and find that issue is towards the dash.
This rig has had some serious flogging and butchering in the past and it will be no surprise as to what I might find on this rig.
I do need to eventually removed the air cowling and clean the engine but for now I've just used air pressure and degreaser to get good air flows around the block and too get dirt off where I can see what's underneath the oily grit mess.

Do you know or anyone of a source to download a Service manual for this 318?

I have the Onan engine mechanical Service manual and the JD 318 owners manual but they do not have the wiring diagram nor the tractor service data.

[KE4AVB]

Check you PM Inbox for download link.

[Arkie]

Check you PM Inbox for download link.

Did not receive your PM, not even in the junk mail????(must be in space still circling???)

But I found and downloaded the Service manual that I needed.

Thanks Again.

[Arkie]

KE4AVB: Thanks for the direct download link.
I'll burn a disk for that one.

Got the low oil idiot light going.

Worked ok when grounding the wire at the dash.
I got the air cowling shield peeled back enough to peek in at the low oil pressure switch. and could see the wire broken off the switch and when I reached in with long reach pliers no slack in the wire. I grounded the wire and no dash light, so two problems. Did a bypass wire to the dash light and pressure switch and the switch checked ok. Light also went off immediately when engine started and idiot lamp stayed off a really slow idle. Pleasantly surprised at that one. Oil pressure seems good. The original oil light sender wire is cut or broken somewhere deep inside a nasty mess at the rear of the engine under the battery compartment most likely.
Just left a jacketed bypass wire in place for now.
Seen that all the flywheel starter teeth looked good. (another pleasant surprise)
Some days just go good.
Other days I just have to quit and take the day off and try getting up on the other side of the bed the next morning.

Thanks all for the tips on this Dog.