robert@honda
Lawn Addict
- Joined
- Nov 2, 2011
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Heard this before?
It means the engine is running too lean (too much air and/or not enough fuel). Often, the problem is a clog or debris in the carburetor that is preventing fuel from flowing properly. Usually a jet is plugged, and either the carburetor must be completely cleaned or even replaced.
But I ran into a situation this week where the engine still had surging and rough running with the choke off, even though the mower had a brand new carburetor installed. With the choke to ON, the engine ran smooth, so it was pretty evident it was still running too lean, but how? The trick was recognizing that a "too lean" condition does happen on small engines when the fuel flow is having problems, but can also happen if the fuel is flowing correctly, but too much air is getting inside, a.k.a., vacuum leak.
Pulled the air cleaning, carburetor, insulator, heat shield, and checked all three gaskets, cleaned the mating surfaces, and gave the two bolts that hold everything together an extra 1/2 turn to really seal everything.
Presto. Started on first pull, and 20 seconds later, choke moved to OFF and running smoothly. What started off as a plugged carb escalated into a vacuum leak due to improper reassembly. Both problems exhibited the same symptom.
The preceding story was true. The names were omitted to protect the innocent (and hide the guilty). :tongue:
It means the engine is running too lean (too much air and/or not enough fuel). Often, the problem is a clog or debris in the carburetor that is preventing fuel from flowing properly. Usually a jet is plugged, and either the carburetor must be completely cleaned or even replaced.
But I ran into a situation this week where the engine still had surging and rough running with the choke off, even though the mower had a brand new carburetor installed. With the choke to ON, the engine ran smooth, so it was pretty evident it was still running too lean, but how? The trick was recognizing that a "too lean" condition does happen on small engines when the fuel flow is having problems, but can also happen if the fuel is flowing correctly, but too much air is getting inside, a.k.a., vacuum leak.
Pulled the air cleaning, carburetor, insulator, heat shield, and checked all three gaskets, cleaned the mating surfaces, and gave the two bolts that hold everything together an extra 1/2 turn to really seal everything.
Presto. Started on first pull, and 20 seconds later, choke moved to OFF and running smoothly. What started off as a plugged carb escalated into a vacuum leak due to improper reassembly. Both problems exhibited the same symptom.
The preceding story was true. The names were omitted to protect the innocent (and hide the guilty). :tongue: