KM 56 Combi Motor won't start

Older Homelite's love fresh fuel. Mix up a fresh batch of gas with the recommended oil ratio. Dump out the old gas into an approved container. Remove the spark plug for inspection and make sure that you are getting a good spark. If you are getting a good spark replace the plug and pour some fresh gas mixture in to the tank and follow the manufacturer's starting instructions. Generally they have a primer bulb press that in 5-6 times until it gets firm. Engage the choke and pull on the rope until it attempts to start. Turn the choke off and it should start right up.
If you did not have a spark on inspection replace the plug and repeat the process.

My guess would be faulty spark plug lead.

I recently bought a brand new 372XP and spent the first day trying to start it as per the instruction manual with no success, never even fired once. Removed the plug to find plenty of fuel and that the plug has a good spark. Left it until the next day mainly to allow my arm to recover (& scour the internet for clues). I found a forum that said not to use the decompressor and sure enough without the use of the decompressor button it fired first go with the choke on then I reset the choke & it ran properly on the second pull. The decompressor button can be reset with fine nosed pliers or removal of the top cover by undoing three screws. Good luck it's a great saw once you know how to start it.

Carburetors could be dirty/blocked. Open throttle and spray carburetor cleaner in them, wait a few minutes, then start. Also spray carburetor cleaner again when revving. Should fix it.
Also, try starting with no choke and no throttle. It could be flooding.
Clean spark plugs.

The first thing I'd suspect would be the distributor cap & rotor, but my 2003 PT Cruiser manual says:

1 - Inspect Fuel Injector Pressure Regulator --- Faulty Fuel Injector Pressure Regulator.
2 - Inspect Carburetor Float --- Faulty Choke Float.
3 - Inspect Choke Pulloff --- Faulty Choke Pulloff.
4 - Inspect Choke Thermostat --- Stuck or Improperly Functioning Choke Thermostat.
5 - Inspect Fuel Injector Cold Start Valve --- Damaged or Faulty Cold Start Valve.
6 - Inspect Spark Plugs --- Fouled Spark Plugs.
7 - Inspect Relay - Fuel Pump --- Faulty Fuel Pump Relay.
8 - Inspect PCV Valve --- Plugged or Damaged PCV Valve.
9 - Inspect Carburetor --- Choke Not Operating.

You only have 2 ways to go......1. fuel .....2. spark, if your cranking your bike, first off try this. crank it with no choke . if nothing happens , take your choke pull it all the way out, now crank it.
if it fires, push choke half way in, continue to crank, it should start . If nothing happens a all .

You have to pull out spark plugs, look at them closely . Is it soaked with gas ? or is it dry as a bone ? if it is soaked with gas, clean it up and dry it off, now check your gap it should be alright
but just check it anyways if the gap is to much it will not fire inside the cyclinder, if it is closed
to much it will not fire . take your plug put it back in just the plug wire and rest it up against the
head or any metal surface, now crank your bike if it has a good blue spark your good with the
electrial check both plugs same way . Now if that is ok , then you have to move on to the fuel.
if you have new clean fuel, good , if it is old like lat years get rid of it . drain everything tank and
all of your fuel filters replace, make sure all of your lines are flowing and carb will clean them self.
give it a little bit after it starts running be gentle with let everything catch up. If it needs final

adjustment on carbs take it back to who ever rebuilt them . Good Luck

Is the fuel old or has it been drained and refilled?? Sometimes old fuel will do this. Also make sure the air filter is clean and free of oil/dirt as this will also hinder the starting.

The primer button also is something to check. Push it 7 times, full choke, pull for 5 times, turn to half choke, and the unit should start.

Let me know,

Chip

Basics to check:
1) Spark plug - brown or dark brown - OK
a) is it carbon or fuel fouled
b) is there spark

2) Muffler remove for inspection
a) exhaust screen clean or plugged
b) inspect cylinder wall/piston as the flywheel is slowly rotated
3) Check cylinder compression


Fuel starvation - 'lean fuel' condition
Basic things to check:
1) spark plug
2) spark arrestor in muffler
3) fuel lines and tank filter
4) turn adjustment needles out (counterclockwise) 1/4 to 1/2 turn
Chain Saws:
5) check impulse tube and intake boot for cracks or leaks
*if all of the above are OK and/or do not improve performance then:
Remove Carburetor
6) replace gaskets/diaphragms
a) use a spray carb cleaner to clean jets, holes, and body of carb
b) fuel pump diaphragm goes against the carb body,
then the gasket towards the outside
c) metering gasket goes against the carb body,
and the diaphragm goes towards the outside

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

Drain the fuel tank, look inside the tank to ensure that the fuel line inside still has a fuel filter attached to it.
Look at the on/off switch ensure that both the wires are still attached to the switch securely.
Check that the plug still has spark, if unsure replace the plug.
Check the air filter to ensure that it is clean.
Mix the gas 50:1.

Since there is no background to this, I assume at some point in time, the motor ran ok for you...

The first thing to do is to drain one of your carburators into a glass jar to check for water. If there is water, you will see it separate from the fuel in a couple of minutes. The water is on the bottom. If there is water, you will need to flush the motor with good fuel, one carburator at a time and probably will have to pump your tank.

If there is no water, the easiest thing to try is the following...when the motor starts to bog down, activate the choke. (If you have a side mount box that activates the choke when the fast idle lever is all the way up), you will have to have someone go back to the engine and manually pull the choke lever out. If the motor picks up, the motor is most likely in need of a carb job.

You can then do a cylinder drop test while motor is idleing, momentarily pulling the spark plug wires off of the spark plugs one at a time. If you pull one off and the engine speed does not change, listen for spark at the spark plug connector to the engine. If you hear the clicking of spark spark is probably ok. The issue with that cylinder is probably fuel related...probably a clogged carburator. If one carb is not functioning correctly, they all probably need some work. If you are not into mechanical stuff, you should have a dealer do the work. After the carbs are cleaned, they need to be adjusted for proper idle and idle/air mixture as well as vacuum balanced . If you are going to attempt it yourself be sure to by a manual either from Honda or one after market.

Before the carb job, a good dealer will always do at least a compression and spark check to be sure there is not an internal issue. The spark plugs should be checked at this time and changed out if they look questionable. Only use NGK DR7EA spark plugs not a substitute.

Also, check your oil and be sure it is clean and at the proper level.

There are several other things that it can be, but this is the most common.