Briggs 18.5 hp Wont Run

[kkjfjns2014]

Hello all, I have a 2006 briggs and stratton 18.5 HP [31N707] engine that came off a craftsman. We put it on a small ariens zero turn. It worked very well for awhile, then got it where it wouldn't run unless the choke was on. Eventually it quit running all together. After this my dad parked it and it sat for 2 years.

I decided to try and fix it for him this year. There was water in the gas, so I took that tank off and drained it and dried it in the sun for a few days. I put it back on put in fresh gas. I also replaced the carb and all fuel lines and vacuum lines and filters. I put the choke on and started it and it ran for about 10 seconds, I took the choke off and now it's back to not running at all again. Tried tinkering with the air/fuel mix a bit, still no luck. If you feed it gas directly into the carb it will run. It has good spark, everything else seems to be functioning, I have no idea what else to do. I'm about to pull my hair put. Any advice on next steps would be greatly appreciated. Thank you.

 

[Bertrrr]

Sounds like the fuel pump is not working, I keep a small electric fuel pump on hand to use when I run into an issue where I think the fuel pump is bad. You probably have the diaphram type pump and it has dry rotted over time.

 

[ILENGINE]

Or is this a case where the old Ariens engine had a fuel pump but the craftsman doesn't and it ran as long as the fuel level in the tank was above the carb allowing gravity flow into the carb. And when the fuel dropped to a certain level it no longer was getting into the carb.

 

[kkjfjns2014]

Sounds like the fuel pump is not working, I keep a small electric fuel pump on hand to use when I run into an issue where I think the fuel pump is bad. You probably have the diaphram type pump and it has dry rotted over time.

I replaced the vaccum pump as well and verified fuel flow while cranking

 

[kkjfjns2014]

Or is this a case where the old Ariens engine had a fuel pump but the craftsman doesn't and it ran as long as the fuel level in the tank was above the carb allowing gravity flow into the carb. And when the fuel dropped to a certain level it no longer was getting into the carb.

Think it's getting to much gas? Shouldn't the float in the carb stop it from getting to much gas?

 

[Bertrrr]

If it was getting too much gas it would be running out of the carb, the float may be stuck or is there a solenoid shut off under the bowl ? Post a few pics if you can

 

[kkjfjns2014]

If it was getting too much gas it would be running out of the carb, the float may be stuck or is there a solenoid shut off under the bowl ? Post a few pics if you can

There is a solenoid shut off on the bottom, but I cut it off because the wire wasn't giving a reliable connection. I did notice it blowing some gas back and found out that means the valves may be out of whack. Do you know what the valve clearances on this engine are?

 

[Bertrrr]

That Solenoid needs 12volts to open and let fuel into the machine , if you cut the wire , there's your problem
Also the Solenoid keeps it from backfiring when you kill the ignition
If you have compression and it runs , doubtful you have a valve clearance issue

 

[smhardesty]

That Solenoid needs 12volts to open and let fuel into the machine , if you cut the wire , there's your problem
Also the Solenoid keeps it from backfiring when you kill the ignition
If you have compression and it runs , doubtful you have a valve clearance issue

Yep. Cutting the wire was the wrong thing to do. If you don't want to replace a somewhat costly solenoid, remove the bowl with the solenoid still attached, pull the plunger up and cut it off. That's a poor man's fix for that solenoid. Not exactly the type of repair that is recommended, but it will solve the problem of a bad solenoid shutting the fuel off to the carb.

 

[StarTech]

And then this is done and the engine come into my shop it gets a new solenoid and customer gets the bill for being stupid. Sorry but is how I feel about it but it is one stupid thing that can fixed. Other stupid things can't be fixed.

Oh btw those fuel solenoids are cleanable.