EPA charcoal filled gas caps for small engines - (small story and fix)

Feb 19, 2009
The Woods of NY
Hey everyone, this dawned on me when I was adding fuel to a 2022 briggs CR950 and well the gas cap is huge - it's almost as big as the gas cap on the car. I dismissed this thought...

Fast forward a couple days and I am reading reviews for said 9.50 Briggs engine with that huge gas cap, and something like 45% of the reviews had issues "starting" "running" or engine "locked up" after just a couple of uses some could not even get it going right out of the box.

Now im thinking maybe I should have passed of this one. I picked this under 1 total hour use briggs CR950 Craftsman 3000 psi power washer up non running and "AS IS"- with the first tank of fuel still in it!... kinda...it had white gas in carb and tank - alot of moisture and again was not running. The owner used it under a hour.... once maybe 8 months ago and said they could not get it going again... of course to a normal Joe the warranty on new craftsman products is a challenge and a half to put it nicely to get ANYTHING. fixed. Personally I would not buy or even recommend a new craftsman product for the warranty and if I did not know how to "thinker" and "fix" issues I'd be VERY disappointed in craftsman. The new Craftsman is not the Craftsman of past.😞

Anyways... I do not have a problem spending a hour or two to get something going again... I drained both the tank/carb. took carb apart cleaned with cleaner, blew of the crevices etc. reassembled and started pulling expecting it not to start because there "has to be more" then just moisture soaked fuel and a clogged carb.

A few pull later and it fired right up..... sounds good revs good, nice pressure, no missing or anything abnormal.... over all it runs as a 1 hour old engine should. Turn it off change oil again (Synthetic 10W30) and go to restart it, nowwwww It makes sense you can't get it going again until it cools off and the vapor lock or what ever disappears.

So im on google and reading hundreds of reviews later... This one pops out.
Screenshot 2023-01-08 at 6.23.47 PM.png

And it a WINNER.(y) I believe that was the original owners issue right off the bat.

They over fulled the gas/or moved the power washer ect, gas soaked into the EPA charcoal gas cap clogged up and starved the tank of air thus was hard to restart. They let is set for a few months and a ton of moisture got into the tank somehow or the gas they used might have been like a E10 plus or something like that and now its a 2 or 3 part issue. The air lock issue because of the EPA cap... the bad fuel and clogged carb.

So overall, a lot of the reviewers are not wrong. This is a hard engine to get running... and if you don't know small engines or how to tinker adjust ect, this engine is the wrong choice for you....

BUT ONLY because of a design defect of the EPA gas cap that once soaked with fuel some particles from the charcoal fall into the gas tank and clog the carb also.

After I did this "Fix" it literally starts in a half a pull under any condition... And it even seems to run cooler now as it's getting more fuel and not leaning out.

This has been a PSA on how to get your new briggs CR950 engine running again. :LOL:🙏
Thanks for the writeup. I believe my Honda engine has something similar. I've been unscrewing the cap a little when I run it, to prevent stalling. I've not found an easy way to disassemble the cap.

I purchased the 190cc Honda engine as a replacement for my commercial mower. It's not as good as the original Kawasaki engine, and it's very difficult to start, I often have to pour gas into the carb. It took me a few tries to figure out the gas cap was part of the problem.
Is this motor CA approved? Curious as could be CA and not only EPA
This made me think that maybe they "Clog" the cap intentionally. That way, there won't be any measurement of "vapors" shown. Clearly, 0.5 grams of activated charcoal nestled in a gas cap won't do a **** thing to prevent VOC's from escaping a vibrating, hot, mower operated on uneven ground.
This is just another case of an idea that works in theory but not in practice, like the EPA fuel cans where you end up spilling more fuel.

I understand the reason behind a lot of these ideas, but I can only imagine how many pieces of equipment have gone to the landfill because of stupid things like this, and they end up hurting more than helping.
my rider and newer pressure washer has the gas tank vented into the air cleaner. So when it is running, hot and shaking the vapors get burned. I see this as a good compromise. For OPE that gets stored outside (oh the horror) vented caps tend to let in water so this would be a good thing. No amount of charcoal will do much when sitting unless the design allow for fresh air purge when running, I do not see any of them with that feature.