Gearhead.....First of all, let me say...."YOU ARE....A GEARHEAD
You mentioned something about a jet being open? Does this mean the needle & seat was free moving?
Or...do you refer to the brass bowl nut being open and unrestricted? Snowblowers are like generators....
only used, when you need to use them. As such, they sit for extended periods and the current fuels
we have to choose from are laden with ethanol and other additives which creates problems for us in
the L & G (and snow) business. Going into the engine was probably unnecessary, but valves may have
needed some cleaning and re-seating and surfacing. Not a bad idea. Playing around with the valve
timing.....not a good idea. These engines have an MCR (mechanical compression release) made onto
the camshaft. It gives a small amount of lift to the ex valve just before TDC compression stroke to
let the engine spin freely through this stroke. With piston @ TDC compression....valve clearance
between valve tappet and valve stem should be around .004 to .010
. For years....the specs on these
were .010 on BOTH
valves. Now....I just usually look for .006 to .008
on both intake & exhaust.
The late model HM/HMSK series Brand T engines are leaned out to the max....in order to comply with EPA
exhaust emissions requirements, and as such, the carburetors are somewhat "compromised
" to get to this
point. Chances are....you're gonna need to do some carb work in order to get her running properly again.
As far as the RED HOT
muffler.....often in winter, snow is being blown in the dark, and seeing things like
this is commonplace. The very lean condition these engines are having to operate at, is also reason WHY
see this glowing. It's actually....OK