I'm trying to figure out the proper way to check the fluid level after changing the oil on my buddy's tiller. It's a "Yard Machines by MTD" rear tine tiller with a 5HP Briggs with a manufacture date of May 9th 1991. It's been poorly maintained, so I did pre-filter, air filter, new plug, and drained what he called oil (drained for ~24hrs to get all the sludgy SAE30 goop out). Refilled with about 6/10ths of a quart of M1HM 10W-30 SL circa 2013 I got for free but I'm not sure if I'm getting the right reading. Do I take the clean dipstick and just push in as far as I can without threading it, or take a reading fully threaded? I ask this because I don't know the capacity and each method gives a different reading. For example, my 23HP Kawasaki FR691V requires you check the level without threading the dipstick to get the correct level. But it's hard to find a manual online for a 1991 tiller. Anyone have input? I'm tempted to err to whichever reading is higher, that way it's not overfilled, but I'd also hate to run a poorly maintained engine with a low oil level. Thanks in advance.