Not Starting, No spark

[Auto Doc's]

Hi digg7,

I think both of you are correct. The solenoid is intended to physically shut the fuel off, and it prevents backfires and run-ons While the engine is still spinning once the key is shut off. It also takes a lot of the reliance away from the fuel float valve as well. As fuel evaporates from the carburetor over time, the float needle relaxes. This can actually create a flooding condition where fuel can find its way into the cylinders and eventually into the crankcase oil.

In addition, the solenoid acts as a redundant backup safety in the event to coil kill wire fails to ground the ignition coil(s) properly.

For most of my riders I have elected to install an inline fuel shutoff and remove or clip off the stop plunger of the solenoid. I got fed up with them always sticking and having to be cleaned. High heat and fuel do not play well together here in South TX. Along with that I don't mow my grass (weeds) but a few times a year because it does not grow all that fast. My riders mostly spend time pulling carts for my grandkids to ride in.

 

[ILENGINE]

Hi digg7,

I think both of you are correct. The solenoid is intended to physically shut the fuel off, and it prevents backfires and run-ons While the engine is still spinning once the key is shut off. It also takes a lot of the reliance away from the fuel float valve as well. As fuel evaporates from the carburetor over time, the float needle relaxes. This can actually create a flooding condition where fuel can find its way into the cylinders and eventually into the crankcase oil.

In addition, the solenoid acts as a redundant backup safety in the event to coil kill wire fails to ground the ignition coil(s) properly.

The afterfire solenoid has no effect on the float valve, or fuel flowing into the carb. So as the fuel in the bowl evaporates it will be replaced with fuel from the tank in a gravity flow situation. If the float valve fails the carb will still overflow and flood the engine,

The only purpose for the afterfire solenoid is to prevent the shutoff bang. It has no other effect on the carb, And in the case of Kohler engines the fuel afterfire solenoid only shuts off the high speed jet but the engine can still draw fuel through the idle circuit, which is the reason it is recommended that you shut off Kohler engines at full throttle.

 

[Auto Doc's]

The afterfire solenoid has no effect on the float valve, or fuel flowing into the carb. So as the fuel in the bowl evaporates it will be replaced with fuel from the tank in a gravity flow situation. If the float valve fails the carb will still overflow and flood the engine,

The only purpose for the afterfire solenoid is to prevent the shutoff bang. It has no other effect on the carb, And in the case of Kohler engines the fuel afterfire solenoid only shuts off the high speed jet but the engine can still draw fuel through the idle circuit, which is the reason it is recommended that you shut off Kohler engines at full throttle.

Unplug the solenoid while it is running at any speed, let me know what happens.

 

[ILENGINE]

Unplug the solenoid while it is running at any speed, let me know what happens.

On the Kohlers you can full choke cold start them with a failed fuel solenoid. I have seen it more than once in my career. I have even limped them into the shop. As soon as your open the choke they die, but will run roughly on full choke with the solenoid either not energized or stuck shut.

 

[Auto Doc's]

On the Kohlers you can full choke cold start them with a failed fuel solenoid. I have seen it more than once in my career. I have even limped them into the shop. As soon as your open the choke they die, but will run roughly on full choke with the solenoid either not energized or stuck shut.

Hello ILENGINE:

I don't disagree with you, and I have used that same process myself when a solenoid fails. It works sometimes and others not.

The other term used for these which is technically correct is "after fire solenoid". After fire occurs when fuel is drawn into the hot exhaust system and ignition spark has been shut off.

Most people use the term "backfire" because it is the most familiar term that has been around and taught for many years.

 

[slomo]

Thanks for being so argumentative. Whatever.

Put down you juicebox and take a breath guy. Getting all fired up on a mower forum is pretty silly.