Fill to the FULL mark on the dipstick. The engine will take 20oz if completely dry. Check the level every time you use it.

So just fill to the line on the dipstick even though I only added 12oz? A lot of what I have read says 18 to 20oz. I dont think I would have left 8 oz in the engine.

The dipstick will tell you how much oil is in the sump. Just add oil until it shows full. You must measure with the dipstick because when you start filling there is no way to tell how much residual oil is in the sump but below the dipstick.

So does 12 oz. sound like enough? I am new to honda but that seems like it isnt enough. From what I have googled it seems like people are adding 16 to 18 oz.

So does 12 oz. sound like enough? I am new to honda but that seems like it isnt enough. From what I have googled it seems like people are adding 16 to 18 oz.

Please, please, please just use the dipstick. It is the ONLY way to determine how much oil is in the sump. Or ask a qualified mower mechanic to do your oil changes.

If there were 4 ounces residual in the sump and you added 20 ounces it would be overfilled.

That crazy '12-13 oz' is some kind of typo. I've seen it a number of times relative to the GCV 160 and GSV 190, and just like you posted they say in the same sentence that it holds 18.56 oz (something like that, as if we can measure oil to the hundredth of an ounce). I found that if you put in 20 oz which is the normal lawn mower oil change, the level is a tad high and it will leak oil from the governor rod where it enters the crankcase. So, I started measuring 19 oz. and it comes out good on the stick. Definitely go by the stick, but the question is on the pressure washer, does the engine have a long engine oil fill tube, and does it require you to not screw the cap in to check the oil? On Honda mowers you do not screw the cap in when checking the oil. All other engines I know of have you screw the cap down to check it. How did you get the oil out of it to change? Did you tip over the pressure washer on it's side so the oil came out of the fill tube as on mower engines?

Thanks saxman, the reason I ask is because 12oz. seems like such a small amount. I did as you suggested with not screwing the dipstick in to check the oil, thanks for pointing that out because it is different than the other brands. I did tip it over as suggested, even set it down a couple times to make sure I could get it all out. I have a hard time believing there is still 6oz in the engine though.

It would be ridiculous to take it to a professional mechanic to have the oil changed as I have never taken anything to have the oil changed, and that's for everything from a push mower to big trucks.

It is indeed ridiculous for them to suggest that there might be more than one oz of oil left in the engine. I don't even tip mine - I use a vacuum oil pump that I originally bought to change the oil in a car that I couldn't get under. It works great on small engines.

Dude , don't fret the small stuff just ensure the unit is on a level surface and use the dipstick to ensure adequate oil level a little low is better than overfilled . Oil caryover is never good . As Sax has indicated all Honda equipment that I have owned indicated levels to be checked with dip stick not screwed in .

Is too much oil harmful??

Too much oil is bad for several reasons that I don't feel like typing. It doesn't have to be perfect, but should be close.

PJ: Yes Overfilling is harmful . As RB CG and Sax have indicated fill to upper dipstick fill level(full) mark or slightly less. Check your Owners Manual for information on whether dip stick is to be completely screwed in or not. Overfilling will cause air filter contamination , engine smoking and misfiring..etc. There is even further long term more expensive repairs involved from over pressurization of the oil system which I will not get into . Just take it from us don't overfill Dude ! :)

The main problem in over filling an engine with oil is that when the oil level is too high, the crank can splash into the oil and cause the oil to foam. Under the worst conditions, it can lead to oil starvation and engine failure.

Go by the dipstick level. I have a pressure washer with the GCV190 (I realize you have the 160 model) and the according to the manual you don't screw the dipstick in when checking oil level. I've attached pictures of the oil check and oil change section of the owner's manual. Overfilling the sump can lead to a host of other problems.