Engine Keeps Shutting Down

[smoke171 0]

I have been having an engine problem for most of the summer, but it is starting to get worse. I have a 416-8 with the Onan p216 engine. The tractor starts fine and will run for a while sometimes 1hr and other times 10-15 min and then shuts down and will not restart for another 15-20 min. It will crank just not turn over. I checked the fuel and fuel delivery and that is fine. I also checked the coil with ohm meter and it checks out ok. I replaced it anyway with an extra one I have. Had a similar problem 2 yrs ago and it was the coil. I also do not think it is the safety switches. Any thoughts?

John

[canam1991 2]

first It could be you points and condenser :scratchead:

[KB9LOR 4]

Don't know too much about Onans, but what about a "Low Oil" safety switch? If it does that could be causing the shutdowns, and it would be erratic as your symptoms are. But I am by no means an expert, but it is something to check.

Brian

[smoke171 0]

I replaced the condensor, hopeing that would fix it, but still happens. I was thinking it could be the low oil switch but I am not sure if that causes the engine to shut down, Also I am not sure how to check it. Could the engine be overheating?

[KB9LOR 4]

Yes if the "low oil" switch is going bad it will shut down the engine, or it could be a loose wire on the switch also, which could also give a false signal that the oil is low and kill the engine.

Brian

The "low oil" switch is installed just so that once the oil gets to its lowest operating level it will kill the engine. (Prevents engine damage) So if you know for certain the oil level is okay, then check the switch, and if bad, replace. You can bypass the switch but I would not recommend doing that.

Brian

[smoke171 0]

Thanks for the info, what is the best way to test the switch?

[KB9LOR 4]

I would use a multimeter, you should have a input wire and a output wire, if you put the tester probes on each wire, switch the tester to Ohms, now if you have continuity it means the circuit is open, meaning that the switch is open, killing the engine, or it won't start, now if you have none, it means the switch is not sending the signal to kill the engine, I would do this test when it quits. Now I may be wrong on all this, so I hope someone who knows more about this electrical stuff will chime in here, it would help tremendously.

Brian

[smoke171 0]

Thanks for the help, But it is not the low oil switch. Could it be the voltage regulator? Or, is their a relay switch or something between the starter and the motor that shuts off the ignition. This is really starting to dirve be nuts!

[KB9LOR 4]

Thanks for the help, But it is not the low oil switch. Could it be the voltage regulator? Or, is their a relay switch or something between the starter and the motor that shuts off the ignition. This is really starting to dirve be nuts!

Not sure, you are getting above my head now:) But I can't see it fluctuating intermittantly like it is, But I may be wrong, does it have a rectifier, like a silver box mounted under gas tank, but attched to the dash tower? with all you have checked I am at a loss except for the two thing mentioned above. Keep us posted.

Brian

[Save Old Iron 1,563]

John,

what year is the 416-8 ??

maybe we can start by doing some troubleshooting from the wiring diagram.

do you have a multimeter or tester lite ?

also - make a quick visual check on the wiring coming from the Onan engine to the battery box area. There may be a white plastic connector in that area that may show signs of heavy corrosion or even "browning" of the plastic from overheating of the connector.

search for the word "molex" on this site and you should get a few informative hits.

We will get if fixed. You just don't want to start "guessing" on an ONAN - parts can get pricey real fast.

:scratchead:

[smoke171 0]

I really appreciate all the help. The Tractor is a 1997 with the Onan P216 motor. And I sure know how expensive the parts can get! Yes I do have a multimeter. I have not seen a white plastic connector, but I will look for it. With all the engine covers they sure make it hard to see the actual motor, it took me about a hour just to remove the covers to see the oil pressure switch wires. I will also check out "Molex" and see what I can come up with.

Thanks,

John

[smoke171 0]

I checked the molex connection under the battery and it looked fine I also checked as many connections I could find and they all were tight and had no corrosion.

[nylyon-(Admin) 7,114]

When it shuts down and won't start, is it getting spark? You mentioned that the coil is good, but we need to narrow it down to spark or fuel.

[smoke171 0]

No it is not getting spark, I took to air cleaner off and I could see fuel still sprayng into the carb. So I am pretty sure it is not a fuel problem.

[smoke171 0]

I think it might be the ignition module, but how do you remove the flywheel? I have everything off but the flywheel won't budge. Is their a special tool needed to remove it? I do not want to force it.

[WH nut 553]

Have you checked the fuses under the right side of the battery. I have seen them corrode and loose contact. When it wont start make sure you have power on both sides by checking where the wire goes into the fuse holder

[WH nut 553]

I think it might be the ignition module, but how do you remove the flywheel?

I wouldnt pull the flywheel until you check the fuses, see above p[ost. But if you need to pull the flywheel, use a prybar behind the flywheel, with a decent amount of pressure, then smack the crank with a hammer, make sure you have the nut ot bolt run down to just about the flywheel

[sodbuster 1]

purchase a puller! even if it is a cheap one!! I among alot of others have used hammers!! I will not again! I have a friend who is a machinist,told me that you can create hairline cracks with a hammer!! not visible with the naked eye,all adds to big troubles later!! if you are dealing with points,make sure the condesor is grounded!! after shut down how long before the tractor will restart? be sure to check wire from points to coil for bare spots.heat shrink connectors,no need to be hasty on these connections.how warm is the coil when shut down occurs? :scratchead:

[smoke171 0]

I checked all the fuses, I know it is not them. I was able to get a Onan repair guide and it recommends putting a jumper from the positive terminal battery to the positive coil terminal to see if it starts, if it does the problem is in some circuits bring voltage to the coil. As soon as this rain stops I will try it out.

John

[red rider-46 0]

to smoke 171

We had a 520H with eratic spark tested everything because we had the whole tractor apart with the engine out and all the wiring disconnected. We found some poor connections but still no luck. After checking the staff sargent language manual many times plus all the fuses many more when wiggling the key switch connector we got a reaction so we changed the ignition switch and fixed the problem. Ours was a little different it never started until replacing the switch. Also the older ONANS did have a problem with valve seats coming loose when the engine got warm then messing up the block requiring a short block, but this doesn't sound like your problem if there is no spark when the engine quits. Good luck I hope this gives you some help.

red rider-46

[red rider-46 0]

to smoke 171

We had a 520H with eratic spark tested everything because we had the whole tractor apart with the engine out and all the wiring disconnected. We found some poor connections but still no luck. After checking the staff sargent language manual many times plus all the fuses many more when wiggling the key switch connector we got a reaction so we changed the ignition switch and fixed the problem. Ours was a little different it never started until replacing the switch. Also the older ONANS did have a problem with valve seats coming loose when the engine got warm then messing up the block requiring a short block, but this doesn't sound like your problem if there is no spark when the engine quits. Good luke I hope this gives you some help.