4-cycle engine maintenance. Tips and FAQ's

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4-cycle engine maintenance. Tips and FAQ's
Original Message Jan 16, 2005 4:15 pm

I ran across this from a local Tulsa dealers website, it covers some of the basics and frequently asked questions about 4-cycle engine maintenance. With it being general information I thought we could borrow part and post it here as a helpful thread.

FREQUENTLY ASKED QUESTIONS AND TIPS

Q:My mower was running fine the last time I used it, but now it will not start. What is wrong?
A: IT MAY HAVE STALE FUEL OR DEBRIS IN THE CARBURETOR
If you leave fuel in an engine for more than 30 days the fuel can start to evaporate and leave behind the detergents that are in the fuel. If you are going to leave fuel in your machine over the winter you should put a fuel stabilizer in the fuel, fill the tank up all of the way, and start your engine and let it run for a few minutes at least once a month.

Q:How often should I check my oil?
A: CHECK OIL LEVEL BEFORE EACH START-UP!
Wipe area clean around the oil check plug or dipstick opening to keep dirt from falling into the engine when checking the oil. Always check with the machine on a level surface. On engines with dipstick, keep the oil level up to, but not over the FULL mark. When adding oil, allow time for all of the oil to flow down the fill tube to prevent a false full reading when the level could actually be low and result in engine damage.

Q:What Kind of annual maintenance should I perform on my 4-cycle engine? A: Every year it is important to install a new air filter, spark plug, and change the oil. A dirty or worn air filter will allow dirt into the engine causing pre-mature wear or engine failure. The same is true for your engine oil. Dirty oil has dirt in it! Oil is the life-blood of your engine and when it gets old and dirty the oil breaks down and no longer lubricates and protects your engine.

Q: What is the big deal about annual and regular engine maintenance? Aren't mowers are made to run in dirty conditions? A: The engine on your mower spends its entire life operating close to the ground at high speeds creating a virtual storm of dust and dirt!
The engine must gulp about 12,000 gallons of air for every gallon of fuel used. Because of its working environment, the air available to your engine is heavily saturated with airborne dirt particles.
Knowing that dirt will quickly ruin an engine, most manufacturers equip their engines with extremely efficient air cleaners to filter out the harmful dirt.

As the dirt particles are stopped, they build up and begin to clog the outside of the filter. This reduces the amount of air available to the engine and causes an over-rich fuel mixture which results in the following advers effects:
1) Increase fuel consumption
2) Cause power loss
3) Result in hard starting
4) Create smoke from unburned fuel
5) Produce carbon build-up internally
6) Foul spark plug electrodes
7) Score (scratch) cylinder walls

Burn valves
9) Wear out the engine prematurely
10) COST YOU MONEY!
Damage caused by a poorly serviced air cleaner is not covered under the engine warranties. So, save yourself unnecessary expenses and undue aggravation by keeping the air cleaner properly serviced at the intervals specified in the engine owner's manual.

It doesn't take long to service an air cleaner. Follow the specific instructions in the engine owner's manual for the type filter used. Prevent dirt from falling into the carburetor intake when servicing your air cleaner. Make sure components are installed in correct sequence after servicing to prevent unfiltered air from entering the engine.

Some servicing hints on several common types are:
Generally, wash foam-type filters in a dishwashing detergent and water solution. Rinse and wring dry, then saturate with oil and squeeze out excess. Failure to re-oil this type filter will ruin the engine.
Clean paper elements by tapping lightly. Blowing with air will rupture paper elements. If too dirty or damaged, replace it with a new air filter specified in the engines owner manual.

Use a flashlight to detect clogged or torn paper elements - replace if damaged in any way.
Air is also needed to keep your engine cool. Dirt, dust & debris build up to restrict and clog cooling air intake screens and fins. Clean screens and fins at frequent intervals. The engine blower housing and shrouds should be removed at least once each season or more often under dry, dusty conditions for a thorough cleaning of fins.
Failure to keep external surfaces clean not only presents fire hazards, but causes overheating and resulting engine damages such as:
1) Distorted valve guides
2) Sticking valves
3) Scuffed, scored cylinder walls
4) Overspeeding
5) Loss of power
6) COMPLETE ENGINE FAILURE
Dirt can also be introduced into an engine in dirty fuel from a contaminated container. Always use clean, fresh fuel from a clean container to guard against dirt, sludge and water contamination.
Be aware that fuel breaks down in storage and forms gummy compounds which will block carburetor passages. Never use fuel more than 3 months old. Add fuel stabilizer or drain tank, then run the engine out of fuel before storing during the off season.

Source: Smith Farm and Garden. Tulsa OK.,
OK. City, OK., Lewisville Tx.

This message was modified Jan 16, 2005 by Marshall

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