Engine 725 Kubota Gas problems.

[kaama82]

I have a new to me. 725 Kunota gas mower. Problem seems to be extremely rich when I give it any throttle. It will idle smooth, but as throttle is applied, it seems to miss and sputter, black smoke comes out the tailpipe until it almost stalls itself out. I can pull the throttle back and it will take about 15 seconds and it will cleans itself out. Ive replaced the plugs, cleaned the carb. performed a leak down test on the cylinders, checked compression, I think that is it. I did find something in Google where a guy said he had the same problem and he was told to replace the carb, but I think that is extreme, Ive been working on small engines for 20 plus years, and never have I had to buy a new carb. Anybody have this same problem? or any more ideas????? BTW... New member here. First Post. Thanks.

 

[kaama82]

I have found the problem. Or at least a buddy of mine did. There was a fiber washer missing in the carb. It went on the carb bowl bolt. There is suspose to be a washer on the outside of the bowl and one on the inside of the bowl to take up the space between the pilot tube and the bottom of the bowl. With the one missing on the inside of the bowl, gas was getting drawn right up the pilot tube without going through the main jet, createing the rich condition off idle....