There is no joy in Mudville - mighty Kohler has struck out

[MossRoad]

Well, its just a fuel issue, but it feels that way! :laughing:

Two weeks ago I was brush hogging at our tree farm and it started sputtering and not running right. I managed to work the choke and throttle to limp it back to the trailer just in time before it died. Got it home and started poking around. I found that if I choke it a tad more than 1/2 choke, it runs fine. So, that means too lean, not enough fuel.
- I made sure the fuel line is clear all the way to the fuel pump.
- Changed the fuel filter that was in that section of line.
- Made sure fuel is coming out of the fuel pump to the carb.
- Repair manual suggests the low idle screw adjustment.... guess what? Where the low idle screw is supposed to be, there's just a plug.

Anyone know if that plug comes out? Or is it a factory sealed non-adjustable deal?

I think I'm going to replace the fuel pump for starters. Even though fuel is passing through the pump, I wonder if its supposed to supply more than it is? I bypassed the fuel pump and ran the fuel line from tank, through shutoff valve, through filter to carb directly. I filled the tank enough so the fuel level is about 8" higher than the top of the carb. It still runs at 1/2 choke in this condition.

Today, while mowing the lawn, I noticed when I backed up and stopped abruptly, the engine sputters, so I'm wondering if there's a problem with the float/needle. The fuel level was down to about only 2" above the carb at that point. So, again, I'm wondering float/needle or lack of fuel pump?

Inspecting the float/needle is free, so I guess I'll do that first, then replace the fuel pump. If that doesn't resolve it, I'll look for a carb rebuild kit, or a whole new carb.

Any thoughts? Thanks!

 

[lennyzx11]

The low speed idle circuit is only for the idle. So not that. You are correct in that there is more air than fuel going in. The main jet circuit is what
Is being used when mowing.

First guess after the checks you've done.

Something clogging in the main jet in the carb where the float needle valve resides or the float is stuck.
Tapping on the side of the carb bowl kinda like knocking on a door force with a wrench/screwdriver/etc may dislodge it allowing engine to run good for a short time.

 

[LittleBill21]

take the float/needle/bowl off. take the main fuel inlet to the carb off. stick a air blow off tool inside the main line and blow it at 100psi worth of air, also check the main jet for clogs.

 

[SpringHollow]

Sounds like a carb issue to me. I definitely would clean the carb at a minimum. Probably worth a rebuild since that is easy to do or look for a cheap replacement on Ebay. The knockoff carbs are so cheap that recently I bought a spare for each piece of equipment just in case I need to replace the original carb in a hurry instead of rebuilding it. The exception being the carb for my ATV which is insanely expensive. Just a jet holder is $54. Fortunately, it is easy to rebuild but for the price of a rebuild kit for the 2005 ATV, I can buy 7 replacement carbs for one of my chainsaws. Two years ago, my source for alcohol free gas went out of business so I had to use ethanol gas with the alcohol gas additive. Almost every piece of equipment with a carb has needed rebuilding in the last year. Fortunately, there is now a new supplier of alcohol free gas.

Ken

 

[the old grind]

Water in fuel or condensation collecting in the carb can cause lean running ... just before it shuts you down. It'd settle in the bowl's main jet well and look like bubbles in gas you'd drain from there. (you knew that)

'Gasohol' can absorb water. As alcohol (emusifier) evaporates during long sits that water can separate out and settle in low spots, but doesn't need to do so to wreck stuff. (you knew that, too)

btw, something to consider when replacing fuel filters on SGEs ... most see-throughs filter to only 40-50 microns, metal can types to ~10 or so and IMO worth the extra bucks even if you can't peer inside 'em.

Like the guys say, plenty of c-air when using dips/sprays to clean. The plug over idle adj access is to deter DIY tweaks (emissions) but prevents such for a restricted idle jet or air passage, and those can be the toughest to clean/check.

 

[oldpilgrim]

did it sit idle for along period of time before use? if so, could be a plugged up carb due to bad gas.

how fresh is the gas you put in it?

 

[RalphVa]

I'd try some Seafoam additive before taking the carb apart. I've cleared up several engines with partially stuck carburetors with Seafoam.

Ralph

 

[Digger 258]

MR,

Mine (with the Kohler) did exactly what yours is doing. I found the ignition switch to be bad, which was not triggering the fuel shutoff solenoid. In the process of figuring that out, I pulled the carb apart, cleaned it with walmart carb cleaner and compressed air. I tested the fuel shutoff solenoid on a battery to confirm it was working. Put it all back together and it runs like a champ now.

I was surprised that the engine would run with the fuel shutoff solenoid in the "shut down" mode while I had a bad switch. It required just over half choke though.

Bottom line, clean the carb, ensure the switch is energizing the fuel shutoff solenoid and I think you will be good to go.
Regards.
Digger

 

[SpringHollow]

Digger,

That is definitely not a cause I would have thought of (the ignition switch). Your posting that will probably save some people grief.

Ken

 

[MossRoad]

Thanks for the replies!

Sea Foam, no difference.
Water in fuel... very unlikely. I rotate it out very frequently and use the tractor often.
Ignition switch... I just changed that last year along with the starter.
Fuel shutoff solenoid... hmmm.... I'll look. Thanks!
Gonna pull the carb open and check and clean the needle area and blow it out with compressed air first.

Will report back. Thanks again for the suggestions. :thumbsup: