GENERATOR WONT START

Question edited for clarity and spelling 'Oman (the country) to Onan.
Question moved to RVs, guessing this is an RV Generator?

Troubleshooting

https://www.google.com/search?q=onan+5500+generator+troubleshooting

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The most common cause of portable generators failing to produce electricity is from the loss of residual magnetism. Generators work by moving electrical conductors through a magnetic field. Your generator does not have magnets. ... When the residual magnetism is lost, the generator will produce no power at start-up.

There are a few methods of restoring a generator residual magnetism

12 Volt Generator Battery Method

Locate the voltage regulator for your generator.Unplug the two wires that connect to the generator brushes. Normally one is red and the other is black or white.Connect the black or white to the generator ground battery terminal.Plug in a light, turn on the generator breaker or switch and start the motor.Connect the battery +12 volts (red cable) to the red wire on the terminals you removed for three seconds.Remove your wires and replace the plug. The generator should now be producing power again.

Make sure you unplug the brush wires from the automatic voltage regulator or you will damage the regulator. Do not contact the voltage regulator or other wires as dangerous voltages may be present that can cause electric shock.

Generator Replacement (LA1)

Removal Procedure

1. Remove the battery ground (negative) cable from the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure .
2. Rotate and secure the engine forward to access rear generator bolts. Refer to Rotating the Engine for Service Access in Engine Mechanical - 3.4L.


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3. Remove the generator B+ terminal nut.
4. Remove the generator B+ lead.
5. Remove the generator electrical connector.
6. Remove the drive belt from the generator. Refer to Drive Belt Replacement in Engine Mechanical - 3.4L.


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7. Remove the generator front bolt.


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8. Remove the generator rear bolts.


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9. Remove the generator from the generator bracket and position the generator above the drive axle.
10. Remove the drive belt tensioner. Refer to Drive Belt Tensioner Replacement in Engine Mechanical-3.4L.
11. Remove the generator bracket. Refer to Generator Bracket Replacement .
12. Remove the power steering pipes from the power steering pipe retainer.
13. Remove the fuel pressure test port (schrader valve) cap from the fuel injector rail.
Important Do not disconnect the power steering pipes from the power steering pump.

14. Remove the power steering pump and reposition the power steering pump in front of the timing chain cover in order to provide access for the generator. Refer to Power Steering Pump Replacement in Power Steering System.
15. Remove electrical harness from retainer on right fender well and position aside.
16. Remove the generator from the vehicle.

Hope this helps?

Visit the on-line store, know as reliable-store, they have the repair manuals. I'm sure you will get the solution of your problem. Best Manuals

gasoline generator I suppose? re-clean your sparkplugs, check air-filter, and adjust your carb to run leaner. if its diesel lemme know

Thankyou Keithdandy. It seems you know what you're talking about and even read the bit about it being a DIESEL (no plugs or carb). It's dark and we're tired now but we will certainly look at the valves first thing in the morning. (the mist bit gave it away!!) thanks again.

Jiggle the wire connectors going in to the computer under the hood -- first check battery cables/terminal connections at battery -- beleive it or not, connection could SEEM good because you get crank & lights, but if it's faulty, loose, engine won't start - computer requires good solid voltage flow.. next check a fusible link very close to the battery off of the positive cable. check fusible link carefully. this could cause your problem for sure.

Sounds like the body control module for the light issues,the fuel gauge works off of the fuel pump , sound like maby the wire come loose at the pump . temp gauge make shure after you replaced the intake gasket that you didnt get a wire to the temp sensor pinched or next to something that could have melted the wire,If the wire gets hot and melts it will go to ground and cause alot of the probs your having in the dash, cause the wire will ground out and send signal to the body control module which in return cause all kinds of beeps and lights to malfunction.If there is no short it is the body control mdule has gone bad and if replaced should fix your problem.

check the air filter if its clean take the carb apart and clean it with something like b-12 or i use wd-40 on my bike so it wont eat the rubber gaskets