Make no mistake about it............
EPA ratings do show an intent of design, component life.
Ben Walker, Nevada Walrus, and Brent Denny touched on it
EPA/CARB....AND.....engine makers worked together on the rating, and it's a Federal mandate so buyers can judge compliance AND quality. A Federal requirement so people don't get bamboozled....which is obviously happening.
The rating that will---is causing alot of misinformation, misunderstanding, and lots of confusion is EDP.
EDP can stand for two things, but is only germaine to EPA/CARB.
Engine Durability Peroid (EDP) is one.
EMISSIONS Durability Peroid (EDP)is another, but the key phrase.
It was smartly FORCED on the engine makers for you & me.
The Consumers....the buyers.
It does help....if used properly, BUTT unfortunately....many big names are behind in engine AND emissions development!!!!!!!!!
Let me simplify by providing some examples:
1. Engines must be TESTED & CERTIFIED.
If it doesn't mean much than why...tested & certified?
ALL engines must have a EDP rating of 50, 125, and 300 hours.
Engine types & displacements (classes) have differences.
2. One famous German manufacturer who now makes their own trimmer engines, including a four stroke w/2 cycle fuel makes a trimmer rated @ 50 hours, aka "C" rating, aka "Standard".
Sells for $199.95
Makes another trimmer rated @ 300 hrs, aka "A" rating, aka "Extended".
Sells for $299-$329.
If you pulled them apart, you'll see differences in everything from the clutch all the way to the carb.
Homeowner vs Pro.
Other companies also do similar builds.
3. Another famous Japanese maker (in Homely Despot) rates ALL their engines @ 300 hours, aka "A", aka "Extended".
But to get that rating....if my memory serves me exactly (have their spec sheet somewhere in my office):
*Every 90 days cylinder exhaust port must be inspected- cleaned!
* Every 600 hours or every year...carb must be replaced.
* Recommend every 25 or 50 hours flex cable be removed, cleaned relubed. Ever done that??? It's a pain, and a mess.
Just think about all that maintenance.
What's coming, the why & how has been hidden,
or attention diverted,
or neatly reworded.....from dealers, you, and me.
Deliberately downplayed!!
One soution to emissions has been catalytic mufflers.
Guess what that does to engine life, weight, heat, and price???
Have pictures of melting engine covers.
Try this test......take a piece of white cardboard hold it close to a catalytic muffler. Better yet a piece of newspaper.
Watch what happens.
Why do you think many companies started changing oil formulas, and ratios years ago. Wasn't just because they didn't have anything else to do on a rainy day.
They're trying every which way to reduce emissions.
Some just work alot better than others.