deanp72
I have an older Generac Standby model 04389 7000 watt. I previous had an issue with start and stop and remedied by installing new voltage regulator. Fixed problem. For months it cycled regularly with no issues. One week it did not cycle. The electric went out and it would not automatically come on so I manually started it and it ran for 18hrs and provided electric. When the electric came back on I shut it down. Now it will not start manually. It starts and shuts down. Something sending a signal to shut down. The high temp light is on but it hasn't run to be warm I changed the fuses in the transfer switch. What can I check next. I have an entire carcass to rob parts from.
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grsthegreat
There must be a temp sensor in the unit. Can you provide a seriel number of the unit.
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Peddler
the little two post Klixon near the oil filter should be normally open I think, it is probably bad.  Try pulling one of the wires off and see if that solves the problem.
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deanp72
Model 043893  serial number 4321825  This unit is 16 years old. I installed 8 of these units in 2003 and only one died from being hit with lightning. Heat sensor may be built into the control module
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Peddler
Part number for the thermal switch is G094090 and can be seen on page 17 figure 3.3 of the owners manual.  It is set to close at 294 degrees.  This does not show up in the parts manual exploded view.
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Cobranut
Anyone know why Generac uses switches that close on fault?
Common engineering practices dictate open on fault, so a bad connection or broken wire cannot disable the switch. 
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78buckshot
One easy way to shut down the engine is to kill the spark to the plugs, on a magneto system all that is needed is to ground the coil, the high temp and low oil pressure switch provide that ground.
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Cobranut
Then how does it start with the coil grounded?  Does it crank until oil pressure builds before getting spark?
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deanp72
You seem to be the best so far. You are not going to like this because it has to be so long. Today in a snow storm I went out and tried starting as usual. Start and shut down with High Temp light showing. I disconnected the Thermal switch as you described and wow it started on manual. I thought it was fixed until I tried setting the exerciser and then it shut down again.
Tried to start on manual and it shut down after starting and now the Low Oil light is on instead of the High Temp light. I disconnected the oil sending unit and it started on manual just fine. I shut it down and tried to set exerciser and it started but would not set. I then checked the fuses in the Transfer Switch and had 1 bad. I changed them last week with new ones but one must have been bad or else I have problem that is causing all this trouble. After changing the fuse it all works fine at the moment. I have a new sending unit in stock and will order the Thermal switch . Will wait to see what's next. Maybe the Motherboard is going bad. I thank you for your help. This Forum is great and possibly I can help someone. I have kept these 8 units going for 16 years but realize that they won't run forever.
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78buckshot
Cobranut, the controller has a time delay when the unit is in "start" mode, it holds the grounding circuit open for a few seconds to give the oil pressure a chance to open the switch.
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deanp72
In working on disconnecting the oil pressure gauge in the snowstorm I think I cracked it. After hoping that my problem is solved I discovered the oil leak. I have a new oil gauge and also a new thermal unit coming. I hope this remedies all my issues. I have another question: If the automatic transfer switch does not kick on in a outage what do I look for. I really think we are good to go with all your advice but just in case. Thank you for all your help.
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