NEED HELP QUICK!!!!! 12.5 kaw

Orkin Yards

LawnSite Senior Member
Jackson, MS
ok, well this engine needs to start because i am supose to be working now but i'm not b/c it won't is the problem....ok it sounds like its flooded, it fires but it won't keep turning....spart plug is brand new, i have adjusted the carb to my best ability which isn't the best... i turned the gas tank off and played with the screw that adjust the fuel bulb thing (it goes up and down like a flapper and controls something w/ the fuel) and it actually ran for like 3 seconds...but when i turn the gas back on it doesn't run...i also turned the gass off and unscrewed that screw and let all the gas drain out and then cranked it till it quit burning gas and then turned the gas back on thinking maybee i had really flooded it and it didn't was doing this last weeka dn it started after a while of pulling but somethings still isn't right....pleaseee help....


LawnSite Senior Member
SW Missouri
I had the same problem with 121/2. Change the oil to 10w-40. I was running 30 weight. When I drained it , the oil looked like mud. Very think, yet not that dirty. Once the thinner oil was in it started better. I did not think the cold weather would cause such a problem.
Tell me it it works for you.


LawnSite Addict
southeast pa
Pull the fuel line off again and blow the line out with an air tip.I didn't here the word "fuel filter". It definitely sounds like you are having a fuel problem. The carb is not gettin gas. I am no mechanic, but that's all I could think of. Usually the blow tip is your best friend in situations like that. Dirt is always a 4 stroke's own worst enemy.

Hope it works out for you. Post here again, and let us know what it was.


LawnSite Bronze Member
SE Pennsylvania
I'd check the carburetor. You might have a piece of sand or dirt clogging a port. Nice thing is 4-stroke carb's are easy to work on. Take it all apart (remembering how it came apart)and spray liberally with carb cleaner. Make sure the float actually floats by placing in water. Before you put it back together make sure the float is dry! I had the same symptoms you are talking about on my 21" a while back and taking apart and clening the carb fixed it. All said and done 30 minutes.

P.S. make sure you spray everything very liberally to wash out anything. You may not see anything (I didn't), but it doesn't take much to plug it up.


LawnSite Member
Lakeland Fla.
Double chek the linkage to the carb. Sounds like the throttle cable may be opening the choke too much. Might have gotten snagged on something. Good luck.

Richard Martin

LawnSite Fanatic
Greenville, NC
In your description it sounds like it's flooding one time and it sounds like it starving for fuel the next. Since you have had the bowl off of the carb (I assume you did since you made reference to the "flapper", it's called a float) the possibility exists that you have lost parts, specifically the fuel needle or that the needle is stuck in the seat. I recommend that you find a friend who knows something about carbs and let him/her look at it. You can also take it to any Kawasaki dealer and get it looked at.


LawnSite Bronze Member
NEVER EVER USE 10W30/40 OIL IN A 12.5 HP SIDE VALVE KAWASAKI unless you live in Pensacola and bring the mower to my shop for a bit of valve work. If you don't want to believe this then don't but don't forget, I told you so!

If the oil is getting dirty then change it and if it doesn't have an oil filter on it then install one but don't ever use 10W30 or 40.