Q: I am a gardener with a new mower (about six months old), with a Briggs & Stratton I.C. engine. Why is the throttle shaft in the carburetor worn out? It should last longer than six months!

A: I have seen a lot of throttle shaft failure over the years. The problem is not isolated to Briggs engines, as it shows up in Kohler, Honda, Tecumseh and others as well. However, it does show up on industrial engines more than on the lighter duty homeowner engines. At first this might seem strange because the Briggs & Stratton standard engine and the I.C. version use the same carburetor. The only difference is in the air filter. The I.C. engine has a more efficient dual element filter. The problem comes in when the filter is not replaced or cleaned properly and the air flow is blocked, drawing air in past the throttle shaft. This is not filtered air, so dirt is drawn in too. Some of this dirt accumulates on the shaft and grinds it away. The dirt actually acts to sandblast the shaft. The dirt that goes past the shaft causes premature ring and cylinder wear. The solution to the problem is to replace the filter more often. In extremely dusty mowing you will have to change the filter more often. When buying air filters, always use filters from the original manufacturer. You will find them to be of better quality.

Q: My engine is hard to start, sometimes taking twenty or thirty pulls. The ignition points and condenser had been replaced twice and the carburetor was rebuilt, however, the engine is still hard to start. What can be done?

A: Every engine regardless of make needs three (3) things before it will run, namely fuel/air, ignition and compression. Because you already had the ignition and carburetion work done, and a quick check verified their condition to be good, I suspect a burnt exhaust valve.

To those of you who do your own tune-up work: I highly recommend that the first step is to remove the cylinder head and inspect the condition of the piston, rings, cylinder and valves. Then decarbon the head, piston and valve area. Decarboning can, many times do more to restore lost power and ease of starting than any other tune-up work!

Q: What about replacement parts that aren’t original manufacturer parts?

A: There are a lot of non-original parts available today, and in many cases the parts seem to perform satisfactorily, but some parts don’t last as long as the original. You the consumer should know what you are getting for your money. If a ‘will fit’ part is offered to you, make sure you don’t pay the price of the original. If the price is the same, go for the original engine manufacturer or OEM part. If the price is less, then you decide, but know what you are getting.