https://www.youtube.com/watch?v=eSmNMWTDtZE
I've done compression tests on an older 15hp Johnson and was getting 100+ pound readings also.
Working on cars in the past, compression tests were done by just removing the spark plugs and cranking for a few seconds with the gas line disconnected and ignition disabled. You really don't want too much gas washing down the cylinder walls and ending up in the crankcase.
On the other hand, some say 75 pounds is a good reading too. Try squirting some oil down the cylinder walls and see if that improves the readings. If it does improve it dramatically, the rings may be in question.
Good luck.