06-28-2009, 11:03 PM
Stale gas is the most common cause of DOA small engines.
The fuel passages in small engine carbs are very tiny. They easily gum up. Once gummed up, you're not getting any use from that equipment until the problem is corrected.
I'd bet that you left gas in the tank (and therefore in the carb) and, the gas turned stale thus gumming up the carb. Is there a primer bulb on this mower? If so, immediately after starting, press the primer bulb repeatedly; especially as the engine starts to falter. If the priming gets the engine to surge, a gummed carb is the culprit. Sometimes, if you keep the engine running this way (with fresh gas in the tank), after a few minutes as the engine heats up, the gum residue might be dissolved & pulled through the carb by the fresh gas. If you're lucky you'll be back in business without having to rebuild / replace the carb.
Another trick for a gummed carb is to use WD-40. With the air filter off, spray WD-40 directly into the carb and try starting. If it runs that would also confirm a fuel system problem. WD-40 is highly combustible so, be careful.
At the end of the season, change the oil and then, run the equipment until it dies from fuel starvation. Pull the starter cord another dozen times to pull air through the carb thus purging all of the gas. Now, remove the spark plug and pour about a tablespoon of oil down the spark plug hole. With the plug out, gently pull the cord three or four times to allow this oil to coat the valves, piston, side walls etc. Replace spark plug but do not connect the spark plug wire yet. Again, gently pull starter cord until you feel the greatest resistance. You now have the piston at Top Dead Center and, both valves are closed. You have the smallest volume of air in a now lubricated chamber. Now you can re-connect the spark plug wire. Blow some compressed air into the gas tank to purge that of gas vapor. When you next use this equipment, you'll start by putting fresh gas in a clean gas tank. It should start on the first or second pull and, you'll get some extra smoke for 15~30 seconds as the oil burns out from the combustion chamber.
I learned this procedure in a small engine repair class I took almost 20 years ago. Since following this procedure, I haven't had a problem any small engine I used it on
The fuel passages in small engine carbs are very tiny. They easily gum up. Once gummed up, you're not getting any use from that equipment until the problem is corrected.
I'd bet that you left gas in the tank (and therefore in the carb) and, the gas turned stale thus gumming up the carb. Is there a primer bulb on this mower? If so, immediately after starting, press the primer bulb repeatedly; especially as the engine starts to falter. If the priming gets the engine to surge, a gummed carb is the culprit. Sometimes, if you keep the engine running this way (with fresh gas in the tank), after a few minutes as the engine heats up, the gum residue might be dissolved & pulled through the carb by the fresh gas. If you're lucky you'll be back in business without having to rebuild / replace the carb.
Another trick for a gummed carb is to use WD-40. With the air filter off, spray WD-40 directly into the carb and try starting. If it runs that would also confirm a fuel system problem. WD-40 is highly combustible so, be careful.
At the end of the season, change the oil and then, run the equipment until it dies from fuel starvation. Pull the starter cord another dozen times to pull air through the carb thus purging all of the gas. Now, remove the spark plug and pour about a tablespoon of oil down the spark plug hole. With the plug out, gently pull the cord three or four times to allow this oil to coat the valves, piston, side walls etc. Replace spark plug but do not connect the spark plug wire yet. Again, gently pull starter cord until you feel the greatest resistance. You now have the piston at Top Dead Center and, both valves are closed. You have the smallest volume of air in a now lubricated chamber. Now you can re-connect the spark plug wire. Blow some compressed air into the gas tank to purge that of gas vapor. When you next use this equipment, you'll start by putting fresh gas in a clean gas tank. It should start on the first or second pull and, you'll get some extra smoke for 15~30 seconds as the oil burns out from the combustion chamber.
I learned this procedure in a small engine repair class I took almost 20 years ago. Since following this procedure, I haven't had a problem any small engine I used it on