C 121....Fuel

[kcuttuck 1]

Should I be running leaded fuel in my C 121??

 

 

Matt

[rmaynard 15,434]

Where are you going to find leaded fuel? Unleaded is fine. Unleaded without Ethanol is better.

[Butch 194]

Airports have leaded 100 octane fuel.

[kcuttuck 1]

Ok, so I found in the manual to use leaded or unleaded fuel over 90 octane so I don't have to buy a leaded fuel additive.   Before I read that I filled the tank with 87 octane and ran it for a while. It ran rough after a while and I had to run it with the choke on. Is the 87 octane fuel the reason?

[rmaynard 15,434]

Thoroughly clean the carburetor. Load the tank with regular, unleaded gas, then tune the carburetor until it runs correctly. All of my Kohlers (8, 10, and 12 HP) run on unleaded 87 octane with no problems. I do use ethanol free gas when I can get it, and I don't let an engine sit for more than 30 days with ethanol gas in the fuel system.

 

I have a station that sells e-free gas within 40 miles round-trip, and it is worth the extra cost to obtain and use it in these small engines.

[Wheel-N-It 2,968]

Matt, do you know how to tune your carb??? If not, go to the Kohler web site and download the manual. Sounds to me like you have trash in your carb. I agree with Bob regarding all things Kohler, however I would like to add to that once your carb is cleaned mix your new gas (I prefer 89 octaine) with Sea Foam. To aid cleaning the carb and fuel system mix 8oz Seafoam to 5gal of gas. This is a good finishing touch to cleaning your carb. Running 5 gal of this mixture should be enough for now. Good luck!

[WheelHorse_of_course 99]

My Kohler K-301 runs OK on 87 octane, but it knocks on hills when the mower is engaged. It does not do that when I use 90 octane. I am pretty sure this means I need to pull the head and de-coke it, but in the meanwhile I'll stick with the 90.