Honda 20 hp won’t start

[Selimpete]

Honda 20 hp, electric start, no choke on it, will fire up by putting fuel in cylinder or pumping accelerator pump on carb. Idles when can get it going.
But will not start cold, just cranking it.

 

[jgmo]

Hi,

Sorry you're having troubles.

This could be caused by a failed by-starter (auto choke) or maybe a blockage in the enrichment feed that the bystarter opens.

You'll want to first troubleshoot the by-starter.
Item #15 in the link below

Honda Outboard 20HP OEM Parts Diagram for Carburetor (Auto) | Boats.net

Buy OEM Parts for Honda Outboard 20HP Carburetor (Auto) Diagram

www.boats.net

Start by unplugging the wires and checking the resistance of the coil. It should read between.15.8 ohms to 24.2.ohms.

Next, loosen the screw that secures the hold down (item 16 in the above link) and pull the by-starter off of the carb.

Apply 12 volts positive to the brown-white wire and ground the black-green wire. After about 2 minutes, the pintle valve should begin to extend about 1/4".
Be careful! The coil housing will get hot.
Take the power away and the pintle should retract very slowly as the coil cools off.

If the by-starter seems to work properly then you will need to remove and open up the carburetor by taking the float chamber off because there is probably a blockage in the enrichment feed passage.

It's best just do a thorough cleaning of the carb if that's the case.

Good luck.