250g trailblazer shuts down after 5 mins

[2000pstokeblue]

i posted in here a awhile back about this problem got a little help, but never fixed my problem. the welder has been sitting since then and im back at it again. i changed the oil and gas and got it running again. So here is my problem. It starts and runs fine for a few minutes and then shuts off, when it does this it will have no spark. let it sit for awhile and it will start up and do the same thing all over again. i replaced the coil last time to no avail. I was told to bypass the oil level switch which i can't find, and or something about a magnetic sensor that heats up on the flywheel. the serial #'s i can find are onan motor on a silver tag g903711949, and this one on the stamped tag on the front of the welder by the control setting panel ka859915

[H80N]

Would check the LOW OIL sensor....

[cruizer]

Probably an Onan, oil sensor is under the left side shroud. and may be your problem. 99% of the time its with a corroded connection between the firewall and engine.

[2000pstokeblue]

i cleaned the connector that goes between the motor and the welder itself it's like an 6 or 8 pin im not sure if thats the one on the firewall your referring to, and i found the oil sensor its just 2 wires can i just jump them to eliminate it from the equation? do you happen to know if the bolt for the flywheel is reverse thread there are wires going behind it id like to look/clean. thanks for the quick replies also

[cruizer]

As it runs the problem is NOT with the trigger, so flywheel removal is pointless. You want to check the charging circuit. but never boost this unit. for 13 - 14VDC. Only 2 things shut it down, oil level and not charging. And of course lack of fuel. So when the unit heats up, there may be a lack of vacumn, thus no pumpy, pumpy... This can only be rectified by installing a small 3 psi 12Vdc pump ran off the other side of the oil pressure sensor. I beleve this is the end problem after that fire wall plug. 1 side of the oil pressure is 12Vdc, the other runs to the rest of the system.

[2000pstokeblue]

ok, so just a jumper between the 2 terminals should take care of the oil sensor if thats the issue, and i don't think its the pump because when it stops running theres no spark when you check it

[2000pstokeblue]

and as far as charging goes if it has a fresh charged battery it should run for more than 5 mins just on the battery alone no?

[2000pstokeblue]

so i jumped the oil sensor and i think that was definitely part of the problem, now it will run anywhere from 30 seconds to 10 mins and i can restart it immediately which i was unable to do before, i have an inline spark tester and i can watch the spark get weak and then sometimes brighten back up other times in just gets weak and then no spark and of course it just dies...don't really know where to look now..

[cruizer]

Nope, charging circuit is checked, no charge, and unit shuts down

[mooseye]

Maybe a double/recheck of all the ignition wiring connections? You can buy a new "bad" coil also Do you see a condenser anywhere?

[mooseye]

You may know and have checked, but the resistance between + and - coil terminals should be 2.9-3.6 ohms and between the two plug wire terminals on the coil should be 14,900-19,800 ohms.

[mooseye]

Oh, and as I think someone mentioned, try to check it asap after it shuts down.

I just thought of the fact that readings will be different at temp. Normal readings are at 70F.

[2000pstokeblue]

I will recheck the coil mooseye, and to cruiser not sure I understood your post are you saying no to it shouldn't run for 5 mins on a good battery? and the charging system must be my problem based on what has gone on so far?

[Kpack]

I will recheck the coil mooseye, and to cruiser not sure I understood your post are you saying no to it shouldn't run for 5 mins on a good battery? and the charging system must be my problem based on what has gone on so far?

What does your multimeter read at battery when running ? Should show more than 12.7 if it's charging. I believe that's what he wants to know if it is charging. The machine has to be charging .

[MMW]

You mentioned changing the coil but have you changed the points & condenser also? Not likely the points but bad condensers can do weird things.

Just to recap you have changed coils, bypassed oil switch & cleaned, checked all wiring connections everywhere you can access & looked for any possibly broken or compromised wires that may be intermittently shorting.

Things to check, is it charging? Simple volt meter test on battery while running. Points & condenser new? Hook a volt meter to input side of coil, (this should be +) does it still show 12v as it dies or do you lose 12v coming into coil? This should tell you if your problem is before or after the coil. Have you bypassed the ignition switch to rule that out.