I'm working on a Honda EM5000sx generator,won't start,R&R carb and cleaned out. replaced spark plug..unit has no spark, while cranking the wire from the coil showed 14.3 volts AC.

Check gaskets / seals / piston rings as it sounds like oil contamination is fouling the plugs.

carburetor problems, remove float bowl and clean the passages thoroughly, again. Make sure no contaminants in fuel

check your oil.

Hi,
I have a EM5000SX. My problem is my generator will not start unless I turn the fuel selector to off. Then crank it until it does start, turn the fuel back on. Run's normal . I run this generator for my cabin every weekend.

1. Drain the gasoline.
2. Remove the carb bowl(s) and turn on the petcock to drain the fuel in the lines.
3. Clean out the carb bowl(s) and replace.
4. Refill with gasoline, add 1 oz of Seafoam fuel system cleaner (I'm not a sponsor, I just haven't found anything better) to each gallon of gas. This will stabilize your fuel as well as do a great job of cleaning out the carb(s).
5. Try to start it.

If it still won't start, begin the standard troubleshooting procedure by first pulling a spark plug and turning it over to ensure gas is getting to the cylinder. If so, replace the plug, hold the plug wire slightly away from the plug and turn it over to ensure a spark jumps between the wire and plug. If so, it starts getting complicated. Buy a manual for the bike if you don't have one and follow the troubleshooting steps there.

You need a carb clean and fresh gas, with todays ethanol in fuel it causes havoc in the carb, need to pull it off and dissasebble it and clean every passage and internals then reassemble and fresh gas and you will be on your way, you may have an electrical valve on bottom of float bowl, make sure that is woeking freely be fore tearing into carb

The plug is under the gas tank. They can be difficult to get to and you may have to remove/loosen the tank. If you can remove the spark plug wire you could test for spark. If you have a spark and it still doesn't crank the spark plug is probably the least of your worries unless you drained the tank and the carb (most people don't.)
If you have a spark give a spritz of starter fluid into the carb after removing the air filter and see if it runs for even a bit. If it does fire and doesn't run, clean the carb.
Good luck.

remove the spark plug and wile holding with a pair of pliers
ground the metal side of the plug against the top of the motor on a bare spot
set the run switch to run and crank the engine look for a spark if theirs a spark
re install the plug.
check the gas line at the carb by removing the
hose and turning on the gas valve under the tank.
if gas flows then replace the hose back.
if theirs no gas then you have a plugged fuel line or gas valve
their is also a screen in the tank attached to the valve remove it and install a in line filter
it will be easier to replace later if it happens again.
remove the air filter and crank engine with the choke closed
check for a gas smell in the carb hole by smell after cranking engine.
if wile checking for a smell of gas at the carb and their was none then you can have a stuck float or
gummed up carb remove and dissemble clean and at that point rebuild the kits are only around $20.00 and a float $6.00+.
if ok remove the spark plug again and set run switch to off
place a finger over the plug hole crank finger should be blow-en from the hole
and a wosh of air if ok. go to next step.
if the pressure did not blow your finger off you may have a stuck valve or a bent one
this will require removing the head for repairs.
take in for service.
if there is no spark with plug removed remove wires from the run switch and connect
together and remove wire from the low oil sensor crank. if spark replace the wire back
on low oil sensor crank if no spark replace the low oil sensor reassemble run.
if the is no spark with the wire on the sensor then replace the run switch.
re assemble run. if their is no spark with oil sensor disconnected and run switch wires
connected to each other remove the front air flow cover to expose the coil check wires for any
bare spots repair as needed. on the top on the flywheel theirs a coil their will be a spade plug
or a wire small that is a kill wire disconnect and crank check spark if spark then that wire is shorted
in the loop and you have to trace it it will go to a wire stud mounted to a plate under
the carb with a plastic mount this can be cracked and shorting bypass and try again still
no spark use a match book cover and lower the coil to the flywheel with the match book cover
in be tween and disconnect the small wire crank if no spark the coil unit is the issue replace
some people will say sand clean the tops of the magnets built in to the flywheel this is a myth
it don't matter but feel free to clean anyways it don't hurt.
this seams allot but it is a complete diagnoses the fuel,spark and air system if all this is ok and still don't run you have a serious internal issue the engine will either need
major work or replacement. i hope this all helps you.

remove the spark plug and wile holding with a pair of pliers
ground the metal side of the plug against the top of the motor on a bare spot
set the run switch to run and crank the engine look for a spark if theirs a spark
re install the plug.
check the gas line at the carb by removing the
hose and turning on the gas valve under the tank.
if gas flows then replace the hose back.
if theirs no gas then you have a plugged fuel line or gas valve
their is also a screen in the tank attached to the valve remove it and install a in line filter
it will be easier to replace later if it happens again.
remove the air filter and crank engine with the choke closed
check for a gas smell in the carb hole by smell after cranking engine.
if wile checking for a smell of gas at the carb and their was none then you can have a stuck float or
gummed up carb remove and dissemble clean and at that point rebuild the kits are only around $20.00 and a float $6.00+.
if ok remove the spark plug again and set run switch to off
place a finger over the plug hole crank finger should be blow-en from the hole
and a wosh of air if ok. go to next step.
if the pressure did not blow your finger off you may have a stuck valve or a bent one
this will require removing the head for repairs.
take in for service.
if there is no spark with plug removed remove wires from the run switch and connect
together and remove wire from the low oil sensor crank. if spark replace the wire back
on low oil sensor crank if no spark replace the low oil sensor reassemble run.
if the is no spark with the wire on the sensor then replace the run switch.
re assemble run. if their is no spark with oil sensor disconnected and run switch wires
connected to each other remove the front air flow cover to expose the coil check wires for any
bare spots repair as needed. on the top on the flywheel theirs a coil their will be a spade plug
or a wire small that is a kill wire disconnect and crank check spark if spark then that wire is shorted
in the loop and you have to trace it it will go to a wire stud mounted to a plate under
the carb with a plastic mount this can be cracked and shorting bypass and try again still
no spark use a match book cover and lower the coil to the flywheel with the match book cover
in be tween and disconnect the small wire crank if no spark the coil unit is the issue replace
some people will say sand clean the tops of the magnets built in to the flywheel this is a myth
it don't matter but feel free to clean anyways it don't hurt.
this seams allot but it is a complete diagnoses the fuel,spark and air system if all this is ok and still don't run you have a serious internal issue the engine will either need
major work or replacement. i hope this all helps you. re-post your outcome please.

Lets see is it fuel or spark? Pull a plug wire remove plug. Now clean plug with clean wire bush. Now put wire back on plug ground to engine crank and see if you have spark.
So you have spark it is now time to check fuel. Start by removing hose from petcock on tank and see if fuel comes out you could have a bad vale / switch got fuel. Remove air cleaner and give carb a shot of starting fluid see if it starts now.