Oil Capacity Mystery

13 years ago

The following happened on two mowers today (one has a Briggs 6.5 HP OHV, and the other has a Briggs 4.5 HP). Checked oil when cold and dipstick read well over full mark. Ran mower to warm up oil, poured old oil out. Measured old oil quantity: 20 ounces. Poured in 20 ounces of fresh oil and waited 10 minutes. Checked oil and dipstick showed well over full. The dipstick on both engines is embossed with info stating that the oil capacity is 20 ounces.

What gives? Am I correct that the dipstick should be stuck in all the way and turned until locked to get a correct reading?

Comments (8)

roadbike
13 years ago
Assuming the mower is on a relatively smooth surface, it sounds like you may not have gotten all the old oil out.
chesapeakebeach
Original Author
13 years ago
The mowers were on a level surface when I read the dipstick. I took out 20 ounces and put back 20 ounces, but the dipstick showed the oil overfilled before and after I did the oil change. If I didn't get all the oil out, I don't know where the extra oil was hiding -- I nearly turned the mowers upside down to get all the drips.
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rdaystrom
13 years ago
An I missing something here? You had a mower that was overfilled. Why would you refill it with exactly the same amount of oil that you took out? Regardless of what the dipstick said your method would fail no matter what you did. Draining oil out of the dipstick hole gets "most" of the oil but not all of it unless you hold the engine in a perfect position for a good while. You had a few ounces here and there all over the inside of that engine case. After draining turn it back upright on a level surface and let it sit a few minutes. Then fill it up in stages with enough oil to reach to the full level on the dipstick with it screwed in. Run the engine a short time. Turn it off then let it sit a few minutes and recheck it to be sure it's right.
chesapeakebeach
Original Author
13 years ago
The amount I took out (20 oz) didn't have any bearing on how much I put in -- it just happened to be the same amount. To judge how much to add, I read what was printed on the dipstick, which said to put in 20 oz.

Regardless, I'll remove a couple ounces from the crankcase tomorrow and get the oil to the "full" mark.
gorper99
13 years ago
I always put in about 4 ounces less that what it calls for,then run it for a minute,let set for 15 minutes,then check and top it off.
roadbike
13 years ago
Car engines get over or underfilled by a full quart because the local grease monkey blindly follows the filling guide.
Just use the dipstick for it's intended purpose.
zoulas
13 years ago
I must be tired. I read your question 5 times. You took out 20 oz, put in 20 oz. Before and after the oil was over the FULL mark. It does not sound to me like you have any problem. Just remember, slightly less oil is MUCH better than slightly more.
1saxman
13 years ago
For once, I'm speechless.

The thing's haunted.