I have a lawnmower with a B&S 6.5HP Intek (overhead valve) engine.
It's about 4 years old, and from day one it has always started on the
first pull and ran with no issues. I had finished the lawn a couple of
weeks ago (it ran fine), and put it away. When I took it out again for
the next mowing, it was very hard to start, and it died after about 10
The plug was all "gunked" up with carbon, unburned gas and general
crud. I *thought*
I saw some bits of metal on the plug, but I can't be
sure. I cleaned it, and it ran again for about 5 minutes, and died
So, here is what I did next:
1. Opened crankcase and checked governor system (it was okay).
2. Removed float bowl from carburator and cleaned everything I could
see, with carb cleaner.
3. Drained fuel tank, disposed of old fuel and bought new, fresh fuel.
4. Put in new air filter and new spark plug.
Now, the mower runs, but it still seems to be very rich. It actually
runs okay if I remove the air cleaner, but once the air cleaner is on
it loses power and starts loping, and is way too rich. It also
backfires quite a bit through the carb.
Here is what I'm wondering:
1. Could the intake valve have fractured? If it did (say, a small
piece broke off), could that make the engine run too rich? I'm
wondering this because one day the engine ran fine, and the next day it
was essentially "dead".
2. If the intake valve idea sounds silly, do you think it could just
be that the carb has a problem? I took the carb apart (the float bowl)
and cleaned everything I could, as well as I could. I'm willing to
spend the $35 on a new carb, if someone who has had some experience
with this thinks it may be worthwhile.