my sears riding mower pluses - it doesn't run smoothly - it revs up then down up then down?

Question

my sears riding mower pluses - it doesn't run smoothly - it revs up then down up then down - I cleaned the air filter and drained the carburation bowel - n/g - I have not drained the gas tank yet - Any ideas?

Answer 1

Well you really need to clean your carb....and your jets

Answer 2

This can be caused by a few different problems in the fuel system. Some of them are very simple to correct, while others require a bit of patience and mechanical ability. If you want to diagnose your problem first drain the fuel from the carburetor bowl. Does it have water in it? (you will see the physical separation of the water and fuel, it looks like 2 layers) If there is no water is their dirt, sand, rust, a gel like substance? If not, drain the fuel from the fuel lines and the tank. Check it for the same contaminates that you did for the fuel in the carburetor bowl. If the fuel in the tank was contaminated rinse the inside of the tank with parts cleaneror a similar liquid. Then let it dry. If the fuel line has a filter in it, take it to a repair shop and buy a new one approx. $3-$5. Before you put it back in, look at it. Does it have an arrow pointing in one direction? If it does, point that arrow away from the fuel tank when you install the new filter.
Next to the carburetor. Take a look at the carburetor. If you have a camera handy, take a picture of it, concentrating on the linkage (the metal rods and springs connecting the carburetor to the throttle and choke levers). This picture may come in handy later if you have never taken a carburetor off of a motor before and forget how it goes back and what parts go where. If you cant find the linkage have someone else move the throttle and choke levers while you watch for movement on the carburetor. Now remove the two mounting bolts that hold the carburetor to the motor. The carburetor is now loose and you can now disconnect the linkage, springs etc. Next remove the bowl from the bottom of the carburetor, make sure you work on a clean surface. There will be a float inside (plastic or cork donut shaped piece attached to the inside of the carburetor with a pin). Leave this alone for now. If you are looking down on that float you will see that it surrounds a hollow stem-like structure. It is the main jet, this is where your problem probably lies. Get a straight screw driver (not Phillips head) and unscrew the inside portion of this stem and if you have a straight pin clean out all of the little holes in it. After you have cleaned it clean out the hole that you removed it from with carb cleaner (get it at a hardware store) then screw it back in and reassemble the carburetor. Reattach to the motor using the picture for reference if needed and reconnect the fuel lines. When reattaching the carb and screwing in the main jet be sure to only tighten it so it is snug you don't want to strip that main jet or break the head off a bolt. If anything is too loose on this part of the motor it won't cause any horrible damage, so just snug it up don't go crazy.Put a bit of fresh fuel in the tank and start the motor. It should run smoothly. If you need more information the library has books on small engine repair with pictures too. Good luck

Answer 3

My Sears lawnmower does that. I usually have to clean the air filter and take out the spark plug and clean it. I spray mine with WD-40, then blow air over it to dry it (buy a can of air at Wal-Mart in the electronics dept). Put it back in and it runs fine for a month or so, then repeat the process.
I will never buy another Sears product again.

Answer 4

If its the kind you can adjust the fuel flow ( meter screw in floatbowl bottom) - id try adjusting that a few turns, sometimes theres a small spring around the link to the goverener- this breaks off causing the pulse. If there isnt a fuel metering screw, well then its time to remove the carb and thouroughly clean it. Probably wouldnt hurt to change the fuel filter either.
Kidd

Answer 5

Spark Plug

Answer 6

The short answer is your carb needs cleaning. It needs to be cleaned and rebuilt. It will run like new.