Honda NC31 difficulty in starting engine after storage

[Vinylet]

NC 31 2002 covered 15000 km

After a number of years storage attempts to start the engine have proved difficult

I have thoroughly cleaned the carbs, choke mechanism has been freed, plugs seem to get wet when engine turned over have installed new NGK CR8EH-9 spark plugs

I have checked the resistance on the coils and they seem ok and at times there is a spark on all cylinders although this is intermittent

I have changed the ECU for a unit which I was advised is working

Once in a while it will start on what appears to be one cylinder however this has been no particular cylinder and once managed to get all cylinders firing for a sort time although the exhaust pipes afterwards were showing significantly different temperatures!

The fault may be something to do with the coils, as they appear to have a constant supply to both of the spade connections when the ignition is turned on

Grateful if anyone has any suggestions to resolve this challenge

thanks

[Vinylet]

Apologies title should read NC31 SuperFour

[MadMotoUK]

Check all the wiring for animal interference, mice love snuggling down in things and chewing. Check all connections and remove any corrosion from terminals.

Are all four carb bowl floats correct height?

[magg]

Voltage on both ignition coil spade connectors at ignition turn-on is not indicative of a fault. Ignition coil switching does not commence until engine is rotating. Fuel tap flows when vacuum applied to vacuum hose?

[Vinylet]

Thanks for your suggestions and advice - not been able to resolve as yet having completed above

[magg]

Do you have a powered timing light. If so check that you do have reliable ignition coil output.

[CMSMJ1]

I'd also chip in with a good old spray of carb cleaner at the intake when it is spinning over - if there is a spark, it should ignite some of that!