Gotcha with small engines and lean carbs

With the weather getting warmer I’ve been going through my yard equipment, and one thing I havent used in a bit was a Homelite Pressure washer I picked up at one of the big box hardware stores a couple years ago. I tried to use it either in 2019 or 2020 and found it wouldn’t build pressure, so I figured either the relief valve is stuck or something else happened. This model has a Honda GCV-160 4 cycle gas engine on it.

So I figured it was time to get it going as some of the walls in my driveway were lookin mossy. I found this this video on Youtube that has to be the best no-nonsense video on how to fix the stuck relief valve. Unfortunately mine did’t want to come out, but a little persuasion in form of a slide hammer did the trick, although I damaged the valve in the process.

The valve ripper 9000
Left o-ring retainer got damaged – also make sure that little hole is clear! (Its clogged in the pic)

Interestingly, it actually still works, but it occasionally sticks. Ill prob order a replacement, but once I got the valve working, I figured I’d open up the carb as I forgot to drain the gas out too. On a positive note, I had gotten ethanol-free gas at the time, and the carb looked IMMACULATE. So I bolt the carb back up, leaving the air filter off, and it didnt run right at all. It ran good with full choke, but super lean with choke off – spitting and popping.

I took the carb off two more times, verified every passage was open, checked the emulsion tube, float, and even the two fixed jets. All good and clean! Why is it not running right??

Then it dawned on me…modern gas powered yard gear is tuned super lean from the factory, and having the air filter in place would include its own restriction, so I put it all back together, and now it runs fine. Some often say to even open up the jets on some things, as they break in or wear down and lose a little compression, the lean carbs will be too lean for them to run right.

Moral of the story…if you have a pressure washer, make sure you use the gel/treatment on the pump after every use, and if working on modern small engines, you really do need to put the air filter back in place, even for testing.