MY ONAN 4000-RUNS FOR ONE HOUR AND DIES--ANY IDEAS WHY?
I have same problem on a PRO500e portabe generator as well. I have replaced fuel lines, fuel filter, carburetor (new), spark plug, air filter. Checked compression, is very good, unit burns no oil. I have known original owner since new. Unit has less than 100 hours on it, so I do not suspect internal engine problem.
Unit ran about an hour then died, restarted then ran about 10 minutes then died. Now runs about 2 minutes then dies.
I am suspicious of the "Oil Watch" system. Going to check that next by disconnecting it from ignition primary and test that way......
If your unit is running fine and then all of a sudden it just shuts down it is usually that you stopped creating voltage. You need to check the brushes and rings. If you are able to start the unit right up without any hesitation and voltage is being produced, then your fuel pump is breaking down. If you do have hard time restarting then you may have clogged fuel filters. One at the carberator and one at the fuel pump.
Does it have original oil in it? if so they use a lighter weight oil than recommended for engine break in. change your oil and filter and see if that doesnt solve it.could be thinning out loosing pressure when hot. i have seen this beofore.. :)
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No. I have changed the oil, though your explanation would make sense. However, I disconnected the oil watch from the ignition primary in case that was causing the shutdown. The unit still dies even with the kill switch and oil watch solenoid disconnected.
I am now thinking that the fuel tank is clogged. After it died and wouldn't restart, I found the fuel bowl on the Carb had no gas in it even though the fuel tank valve was open. Going to drain and flush out the tank (again).
Thanks.
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