What is the oil filter for onan4000 generator

Who made the motor on it?

See id it is actually pumping fuel and if so see if the glow plugs are getting hot.

Your oil level sensor is bad. It needs to be replaced. If you unplug the wire leads to the sensor you may get the generator to run, but you'll have no low oil level/pressure protection. The oil level sensor is on the engine crankcase usually near the oil level dipstick. You'll likely see a small sensor with a couple of wires attached to it. To replace it, you'll need to drain your engine crankcase before removing the sensor.

1. Heat dissipation, cooling and clogging of the lubrication system cause the diesel engine to overheat.

Blockage of radiator or pipeline: once the radiator and pipeline are blocked, the cooling water cannot circulate and the diesel generator will overheat.

Exhaust pipe blockage:When the exhaust pipe is blocked, when the diesel generator is running, the exhaust gas is not discharged smoothly, and some of the exhaust gas remains in the cylinder. When the next intake stroke is intake, there are more in the cylinder. Exhaust gas, fresh oil and gas mixture can not fully come in. When the spark plug is ignited, the flame propagates and burns slowly, and then burning time is long, forming a post-combustion. Parts that are in contact with gas, because of the long burning time, can not release heat, thus causing overheating, at the same time, due to the unsmooth exhaust gas emissions, the exhaust gas temperature rises significantly when exhausting, and the thermal load of the entire diesel generator increases, causing the generator to appear overheat.

Oil filter plugging: Under normal conditions, the oil of the diesel generator enters the diesel engine through the oil filter. Once the oil filter is blocked, the oil enters the lubrication points of the diesel engine only through the bypass passage. In this way, since the oil is not filtered, it is easy to bloc the oil pipeline, causing poor lubrication, the oil pipeline is blocked, and the heat generated by the friction coupler can not dissipated, causing the generator to overheat.

Oil screen plugging: The oil filter is placed at the inlet of the oil absorber in the oil sump to remove foam and prevent large slag from entering the oil pump. Once the oil filter network is blocked, the supply of lubricating oil to the diesel generator is interrupted, which will cause dry friction of the friction coupler of the diesel generator, which will cause the generator to overheat.

2. The cooling system and the lubrication oil system leak, causing the diesel engine to overheat.

Leakage of the radiator or pipeline: The radiator or pipeline leaks. Because the water storage capacity of the diesel tank is limited, the generator will overheat.

Oil pan or oil pump oil leakage: The oil pan or oil pump oil leakage is mostly caused by loose oil plug or gasket damage. The consequence of the oil sump or oil sump leakage is that the diesel generator oil supply is reduced or interrupted. Since the diesel generator reduces the cooling effect of the oil, the heat of each friction pair of the diesel generator cannot be transmitted, so that the generator is overheated.
More information at this article: https://www.dieselgeneratortech.com/diesel-generators/How-to-Deal-with-Diesel-Generator-Overheating-Problem.html

Maybe it causes by the following problems:

Fuel System Failure

1. Air in the fuel system
This is a common problem that a diesel generator fails to start normally.
Solution: Check whether the fuel oil pipe connector is loose or not, and ensure that the air is cleared from the fuel system. Loosen the bleed screw bolt on the diesel filter, and then use the manual oil pump to pump the fuel until the air bubble is gone.
2. Fuel Line Obstruction
Solution: Check whether the pipeline is smooth or not.
3. Fuel Filter Clogging
Solution: Clean the filter or replace the filter element
4. The Handle Position of Fuel Injection Pump Is Not Correct
Solution: The handle position should be pushed to no-load when starting the diesel generator set. Rotation speed is about 700-900r/min.
5. Fuel Injector Problem - Little fuel injection or fuel injection is not atomized
Solution: Remove the fuel injector, connect it to the high pressure oil pump, pry the fuel injection pump plunger spring and observe the spray condition. If necessary, wash the injection pump.
6. Oil Supply Problem - Oil transfer pump doesn't supply oil or the oil supply is brokenly.
Solution: Check whether the oil inlet pipe is leaked or not and the filter screen on the oil inlet pipe connector is blocked or not.
More information at article.
https://www.dieselgeneratortech.com/diesel-generators/why-diesel-generator-fail-to-start.html

if the filter got oil soaked replace it remove the spark plug and crank it over til no oil sprays out install spark plug start it up it will smoke for a while but let it run without a load til it clears up

Those generators are set up with a low oil saftey but your gonna want to check compression anyways just to verify it is where it needs to be. Im gonna guess its to be between 120-160 psi, check your manual for the service limits. after that check your air filter, valve lash, fuel filter etc etc.

Lowes sells air filters for Kohler engines . As far as the oil a SEA 30 or 10w 30 would be fine.

I have the same Gen. An it dont have an oil filter

You have/had too much oil in it. After it is brought down to proper level, it may have to burn the oil that is in areas that it should not be in. Another thing that may cause this, is a dirty air filter, can cause enough suction to pull oil around valves, and other places a clean filter will not. It may have oil in the filter too.