QuestionHey there. I have an older craftsman rider model 917.252520 mower with a 15hp OHV briggs engine, model number 28N707 code 016201........My problem is the enigine will idle fine and run great with the throttle lever all the way up on choke, but will not run at higher power settings. When trying to run at higher power settings it starts surging, not a quick surge but slow. It will run on high for a few seconds and then acts like it has ran out of fuel and just before it shuts completely off will surge back up to high power and then repeats itself. I have replaced the spark plug and torn the carb apart and completely cleaned it. Also replaced fuel solenoid with reg bowl nut and put fuel shut off valve to rule out it being the solenoid. Any help would be much appreciated. Thanks.
AnswerDaniel
If your carberator has a fuel adjustment screw at the bottom of the bowl try adjusting it in and out 1/4 turn to see if it affects the surging. If no adjustment screw at the bottom of the bowl pull out the solenoid dropping the bowl. Clean any holes both big and small in the side of carburetor then clean our the carb bowl. Put the bowl and screw back in and try again.
MANY coils/modules are fine when they are cold, but die when they are HOT!
If you still have the old spark plug, open the gap to about .075" or so.
When the mower dies, swittch the plug wire to that plug, ground it to the engine block and give it a pull. If you have spark, the coils good.
You might even try it before you mow, just to make sure you can get a spark then.
If The gas you are using was stored for a long time ? If so go buy new gas. If you are using new gas from a filling station that does not sell a lot of gas go to a new gas station with lots of business selling gas trying to get more fresh can of gas. Gas today will separate over time causing what you discribe.
Running your engine out of gas often sucks granuals from the tank through your carb plugging those holes in the bowl bolt I discribed above.
