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Generac generator will start, run for a moment and then shut down,Carb problem or bad low oil switch?

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  • general_acco Jul 11, 2010

    Thanks for the input... I was thinking that the needle valve might be sticking and not letting gas in as fast as it should... for a carb problem. When started, it would use the gas in the bowl and then die...

    I was unsure about the oil level sensor, since it is bypassed when initially started. There are 3 wires that lead to the sensor. Anyone know which ones get shorted/opened? I may just put in a plug, bypass the safety switch and put in a hard gauge to monitor the pressure. I really appreciate our help.




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Its the Oil sensor just pack the oil sensor wires together with a smal screw and bolt and try starting if it starts your problem is the oil sensor they tend to go bad I have run through several myself . To avoid hassles I now have overidden the sensor but I check the oil level everytime I need to use the generator

Posted on Sep 03, 2010

  • GhostRapscom Sep 06, 2011

    Here's the fix for your Generac 4000xl if it starts runs 7 to about 15 seconds then shuts off! My generator only had 15 hours on it when it crapped out. Most Likely it is the Oil Sensor! The oil sensor which is behind the muffler and has 2 yellow wires going to it. Remove the 2 yellow wires. Make sure the first nut is tightened down or oil will leak from the sensor. Put the 1st washer & 1 nut back on sensor so they won't get lost. Now for the 2 yellow wires... either use a small nut & screw to attach them together securely, or wire them tightly together. Use electrical tape to cover/secure the 2 metal loops on the yellow wire. Secure the yellow wires so they will not come in contact with any hot surface. You are done! Took me about 5 it works like a champ again. Just make sure to check your oil & change it regularly. I'm not putting a new sensor in, it's just a waste of money. Generac of course admits and covers nothing as to this being a systemic problem.


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It is rather the oil switch or its level sensor, because the carb should not let it start.

Posted on Jul 10, 2010


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