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

Good morning all:

I have a Simplicity 1060E (B&S Intek OHV, 10HP engine) that is 3 years old. From the beginning of the season, the engine ran rough, stalled easily under loads that normally wouldn't be a problem, needed a lot of choke for a long period of time to warm up. Was stored off season with stabilzer in gas.

Finally had a break in the weather last week. Repair shop picked up machine, cleaned and rejetted carb. Said problem is due to ethanol in gas (now mandatory in CT is " as MTBE is banned). Engine now runs well.

What exactly is "rejetting" a carb?

Thanks in advance.

Fran

Carb jetting is usually cleaning the carb and setting it back to factory specs and or replacing the Jets if they are being restricted by deposits build up.

a carb jet is an orfice that meters the amount of fuel supplied by the carb to the engine. to "rejet" one changes the jet to a smaller orfice if an engine is running rich, or to a larger jet if its running lean.
this adjustment is based on several factors but to put it simply it depends on how the engine is running & the condition of the spark plug.  a black sooty plug will indicate a rich condition....white and blistered in some cases too lean. ideally a plug will be a gray to brownish color when the proper fuel mixure is obtained

Sounds to me as if your engine was running lean (needing to run on partial choke & rpm surge are the most common symptoms). In any event, rejetting or drilling out the existing jets slightly can often solve the problem.

Poor performance, surging, engines that will not run with the choke in the full off position, etc., have become very common problems in recent years, as emissions regulations have forced engine maufacturers to run their engines a lean as possible to reduce pollution & meet regulations. In spite of using a fuel conditioner (such as Sta-Bil), the slightest amount of debris or fuel varnish/gum deposits will cause problems.

Sounds simple enough, but here's the caveat...

Be warned, shops that knowingly tamper with emissions related components on a CARB or EPA certified engine (basically all engines built since the mid to late 90's) can be fined up to $25,000.00 by the EPA. Equipment & machine owners can be fined as well (up to $2,500.00), if they knowingly tamper with any component that can affect the emissions on a certified engine.