I have a petrol generator, it puts out 110 and 230 the switch that changes over is a on/on switch when it was running my mate switched it over to 110 from 230 and the was a flash now it does not put out any output from 110 or 230 any idea's whats up ?

it is not any kind of car or truck,so moved you to portable elect gas generators.
does it burn gas/petrol or LPG?
with engine stalled, oil lamp on is 100% normal
but never at the time of stall (or just before)
the oil pump runs off the crankshaft is why.
new spark plug is cure. i bet.
or use chock longer.
carb, gasoline , petrol.
if spark tip is in raw fuel , turn off chock and crank it dry.
the gen has many buttons switches make sure all are set correct for sure on./off .
is it elect starter or hand cord cranked or both?

If your 1997 Mitsubishi Starwagon has been converted to run on LPG (liquid petroleum gas) and is having trouble switching back to petrol, there could be a few different issues at play. Here are a few things you could try:

1. Check the LPG/petrol switch: Make sure that the switch is in the correct position for the fuel you want to use.
2. Check the fuel lines: Make sure that the fuel lines for the petrol and LPG systems are not blocked or damaged.
3. Check the fuel pump: The fuel pump may not be working properly, preventing the vehicle from switching to petrol.
4. Check the fuel tank: Make sure that the petrol tank is not empty and that there are no blockages in the fuel lines leading to the engine.

If none of these solutions resolve the issue, it may be necessary to have the vehicle diagnosed by a mechanic. They will be able to identify the cause of the problem and recommend the necessary repairs.

what is meant by the run time
an 1850 watt unit will run indefinitely if the out put is around 1750 watts but probably 5 minutes at 1850 watts as that is the max wattage for surge start ups ( electric motors switching on as in fridge compressors, drills, compressors)
if you are running it at around 900 watts constant then a tank(20 ltrs) of fuel will probably last 8 hours

are you getting spark , is the on switch on , some people forget to do this

why not post symptoms, and not guess at parts that may or may-not
exist.?
the fuel cut off switch is the ignition key, and works all the time.
The Maruti Alto is the Indian-built version of the fifth generation Alto
796 cc (0.8 L) F8D I3 (petrol)
998 cc (1.0 L) K10B I3 (petrol)
1,061 cc (1.1 L) F10D I4 (petrol)

or
Seventh generation (HA25) Alto from Japan.
796 cc (0.8 L) I3 (petrol)

what engine, the fuel systems vary by engine, and country sold to.
neither sated.

It sounds like the exciter capacitor is letting go after it heats up

Also check the oil pressure switch and oil viscosity

Locate where the choke lever is for your generator (under the petrol tank), you ought to notice a star headed shaped screw connected to the governor shaft (if you bend and look closely further beyond the choke lever; still under the petrol tank) which is linked to the carburettor housing/assembly. You need to increase/turn clockwise (using a star screwdriver) on this screw.

Your generator engine sound will change/high a bit because the engine speed will increase.

Reconnect your 1800w chop saw (load) and see if your generator can "effortlessly" accommodate it without shutting down otherwise, increae the turns on this adjustment screw attached to the governor shaft till your generator operates/stabilizes with the load (1800w) connected

The brushes could be bad or you have burned out the generator.

Need more info,

Does it turn over??

Does it have spark??

Does it have fresh petrol??