On Feb 4, 11:20*pm, Taylor wrote:
My snow blower has a Briggs & Stratton 7.5 hp "Powerbuilt Snow"
horizontal engine. *It has always need a little choke to run smoothly
after it warms up. *With no choke it runs, but stumbles slightly. *With
one click it is a bit smoother, and with two clicks it runs the
smoothest. *More than that, there is too much choke and the engine will
die.

Thinking that perhaps something is clogged in the carburetor/jet, I
replaced the whole carb with a new one. *The result is exactly the same..

I have fresh gas, use Sta-Bil, etc. *I'm not overly worried about it, I
just use two clicks of choke for best power.

However, I suspect that I'm not getting the full 7.5 hp with the choke
restricting air intake. *I'm also curious what the problem is. *A
repairman said that all engines are tuned lean due to EPA rules. *Of
course there is no way to adjust the mixture.

Any ideas what causes this? *Is the repairman right about the mixture
set overly lean on purpose?

Ive never seen a snow blower with an air filter as others state they
have, it would get wet and restrict air thats why they dont have them,
an air filter will make it run richer needing less choke, not more.

How do you know the carb isnt just a poor rebuild, ive seen 6 bad
starters in a row. It isnt getting enough fuel or it has an air leak
at the manifold or maybe somethings cracked or loose letting in air. I
would check the seal if the gasket and check everything. You could
take it apart and run wire through the jets to see if they are
actualy clean and blow it out with compressed air or put in in carb
boil, or enlarge the main jet a bit, but be carefull. Ususaly needing
a choke means you need a carb cleaning from old gas varnishing the
jets, Ive a a bit of dirt logged in a passage do that and compressed
air fixed it.