i have a 2650 diesel mower that runs great then it will sputter and shake like the fuel stop switch is turning fuel off. this last for about 30 sec. to one min. then it takes off and runs great again. then same thing happens again. i have taken the tank off washed it out, let it dry then put camera in it to make sure nothing was there. this happens under load, not under load, going up hill, going down hill and on level ground. thanks in advance for the help, as i need it. david