M-20 dies after 4 or 5 minutes

[Sam Mac]

Have you tried disconnecting the kill wire at the mag?

[J-Mech]

You said this motor came out of a Husky. Did the engine have an Oil Sentry system on it??? I'm staring to lean toward that. Kohler offered the Sentry system on some engines.

[Sam Mac]

Originally Posted by J-Mech

You said this motor came out of a Husky. Did the engine have an Oil Sentry system on it??? I'm staring to lean toward that. Kohler offered the Sentry system on some engines.

You may have something Jon. Just looked up the wiring for an M20 and sure enough they did have an optional oil sentry. My question then would be if it was running before and shut off does the engine have an oil pressure problem?

[john hall]

So is the Oil Sentry an automatic shutoff then, kind of like Murphy gauges on big equipment? If so that makes a lot of sense because his problem seemed to vary with frequency and I believe he already did a spot check on the wiring.

[flatpickerray]

I haven't disconnected the wire at the mag itself, it's still in the tractor. I have disconnected the wire where it plugs in at the motor, I can basically see the whole wire from there to the coil and it's not grounded anywhere.

Yes the Huskee had the oil sentry, which is just an oil light that comes on if you lose oil pressure, and is on when you turn the key on to start it till it's running and build pressure enough to open the switch.

I did put a oil light on the 782. One side of the light goes to a 12 volt source and the other side goes to the wire from the oil sending unit, which is the ground for the light. (no oil pressure- light on, with oil pressure- light off)

I don't see any way this could affect the running of the engine unless there is something internal that I don't know about.

I still suspect a defective coil because the reading between the two plug wires(which is the secondary) is nowhere near what the manual says.

I'm going to see if they'll send me another coil but till then I'm open to all suggestions, Thanks guys--Ray

[flatpickerray]

Originally Posted by Sam Mac

You may have something Jon. Just looked up the wiring for an M20 and sure enough they did have an optional oil sentry. My question then would be if it was running before and shut off does the engine have an oil pressure problem?

Yeah, mine is not wired like that diagram, I still have the original 782 wiring, so the only thing the oil sentry on mine does is turn on the light that I added if I lose oil pressure.

[darkminion_17]

This explains the oil sentry.

http://outdoorpowerinfo.com/repairs/...l_shutdown.asp

[john hall]

Originally Posted by darkminion_17

This explains the oil sentry.

http://outdoorpowerinfo.com/repairs/...l_shutdown.asp

Wow, pretty informative! I didn't realize the shutdown switch was for low oil level. I just assumed it would be for pressure. That answers another question, how would you crank it if it was a pressure switch. We have a farm tractor with Murphy safety switches, you have to manually hold an override button in until oil pressure comes up to get it to crank and run.

[J-Mech]

Murphy switches are a little different, John. Most have an adjustable pressure setting, and once tripped, have to be reset. On a large engine, it takes a few seconds for the oil pump to prime, then fill the oil cavities. On a small engine like a Kohler, you can crank it and it doesn't take very long to build oil pressure. The switch only would need to see 3-5psi to open the connection. When you shut the engine off, it simply closes the switch, and reopens it when it see's pressure again. All that said, I don't think that Kohler used a low pressure shut down switch on this particular engine. However, some purchasing companies may. Example: A motor sold to a company to power a gen set, or a engine set up to run an irrigation pump.


To the OP. I'm sure that the Husky had an oil light, but the low level shut down will be included on the engine harness only. You need to look at the engine itself, behind/below the tins for the low level shut down. It has nothing to do with the tractor it came out of, or the one you put it in.

[flatpickerray]

No J-Mech it doesn't have a low level shut down, it only has the pressure switch for the low oil light.

They sent me another coil and the ohm reading is the same as the first one. So either they are both bad or both good. I am getting spark but not as strong as I would expect. No I didn't by a spark tester yet I haven't been anywhere to get one.

I think I have a two-fold problem. I think the original coil was bad and now I think the fuel pump is bad. I'm pretty sure I'm getting gas in the oil as the level has come up about 1/8 to a 1/4 inch. I've ordered a new fuel pump.

A couple questions- I took the hose off of the carb side of the pump and cranked the engine. Should it be a steady stream of gas or should it be squirt, squirt, squirt like mine did?

Why when I pour a little gas in the carburetor does it not hit a lick and then I take the spark plugs out, they are dry. Could it be sucking that gas out and dumping it in the crankcase somehow?

Does anybody know what the ohm reading of the primary side of the coil should be? The manual doesn't say, it only gives the secondary reading.

Thanks for the help- Ray