Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I had reservations about doing this on a new snowblower, but I have to tell you, this engine runs even smoother than it did before.  After the new carb was installed, I figured it didn't need to be started using full throttle as you normally would have to do.  After two hits of the primer, I raised the throttle to just over the idle position, and it started on the first pull.  In fact, it was much easier to warm up with the modified carb than it was with the original one.  I found I didn't have to manipulate the choke settings to keep it running as I did before. 

After a good warm-up, I raised the throttle to maximum and adjusted the high-speed main fuel mixture.  When the engine smoothed out, I lowered the engine speed to the idle position, only to find it was idling at 1,550 RPM's.  Amazing, because the EPA carburetor had to idle at 2,300 RPM's.  I did a fine adjustment to the low-speed mixture until it was at its smoothest.  What was most obvious to me was just how smooth it ran at any speed.  Normally there was just enough vibration that it would translate to the very long chute on this snowblower, but not anymore.  Aside from the noise these snowblowers make when running, if you grabbed the handle bars, you were only able to detect the slightest amount of vibration.

The only surprise I did notice was that after the carburetor was fully set, the maximum engine speed had increased to 3,500 RPM's.  I did make a minor adjustment to the governor to bring the speed back down to 3,400 RPMs, what it was set at prior to all of this.  Having to lower the governor setting, made it apparent to me just how much power gets robbed from the EPA carbs.  I suppose I have to look at it as the engine having that much more power available when the automatic governor kicks in when under a heavy load.  I'll put this machine up against a 10 hp snowblower any day of the week.

Thanks Marshall.  I ran the thing for an hour and it was just fantastic.  I would have preferred making the carb adjustment at the temperature that I'd most likely be using the machine in rather than this 36 degrees.  If we get some cold temps, I'll be sure to check it again.  There was also no spitting and surging as it did the last time I used it, which was the reason I felt the need to experiment like this.  After the hour it ran, there was also no sign of that mayonnaise stuff on the dipstick, nor was the breather tube spitting any.  Again, I'd have to see if this was also caused by the 14 degree temperatures when I experienced all of this.

MountainMan, If you have an 11.5 hp engine, I would imagine it is an OHV.  If you've had any of the problems I was experiencing with my de-rated 9 hp Tecumseh, this will cure them.  I too understand the importance of the EPA carburetors, however, all of our cars have tons of anti pollution devices on them, yet they run great.  What has been done to OPE carbs must be a cheap quick fix because these engines should not be this finicky or run so badly.  This is the reason I did what I did and I intend to leave it this way. If you modify yours, let us know how you make out.

Until actual part numbers can be determined, I'd have to say yes to your question.  Basically, its the same carburetor, only the bowl and adjustable main nozzle jetting are from a pre-EPA design.  For instance, my original EPA carb bowl had the high speed main non-adjustable jet installed, which is that large nut that holds the bowl to the bottom of the carburetor.  On the new one, that part now has a fully adjustable jet (screw on a spring) installed. This is the rich/lean high speed adjustment that makes all the difference. 

That adjustment screw or "main nozzle" may actually be a standard size on most larger engines, but there is also a a second part to it, a colored tube (green colored on my EPA carb) sticking up into the throat of the carb held in place by two O-ring. The new carb has a brass tube.  I think the best thing to do is contact this person and maybe ask him for a kit to revert your carb, or you can send him your carb and have him do it.  I believe he charges $50.00 to boil out the carb and revert it.  In effect, you'll be getting a new carb back in your hands.

There is a special tool required to install and set these components properly.  Better yet, Snowshoveler (Chris) has all the part numbers at his place of work.  Perhaps he maybe he can determine and order exactly what you need rather than pay someone $50.00 to recondition your carburetor.  I also have a carburetor left over from my 25 year old snowblower.  It too had a Tecumseh engine.  The main nozzle adjustment screw looked exactly like the one on my new carburetor, so these parts are readily available.  In fact, this 25 year old carb was an exact duplicate to my EPA and new reverted carb externally, with the exception that this 25 year old carb had no screw recessed to accept the two screws that hold the metal carb box to it.  It doesn't look like Tecumseh does too much to these carburetors except maybe vary some of the linkages.