"An 18 hp 42" hydrostatic ---" really doesn't give anything to go on since there are several 18 hp engines and what it's on doesn't matter. What is the make and model number of the engine?

did you check your oil level before starting?

Walt Conner

Just to be clear:

1. Has it always done this or is this a recent problem?

2. Does it only spew oil when the blades are engaged? If you engage the blades and the engine spews oil, will it stop when you disengage the blades?

3. Was the mower recently tipped up from one side for service?

4. As Walt said, is it ovefilled with oil?

Sorry I can get the exact model # when I get home tonight.

This is a recent problem, it ran well all last year, it ONLY spits up oil when the blades are engaged, If you disengage the blades it stops spitting oil. It is definately not over filled, now it's super low since it had spit up so much and no it has not been tipped over. It just started happening one day when I went to cut the grass. It's a Simplicity Regent but i'll get the exact model # later.

The engine is pulling harder with the blades engaged. It's a long shot, but is the breather clogged?

Still don't know what engine you have but as roadbike says, might want to check the crankcase breather to see if it is working. IF B&S, max. clearance between the fiber flapper and seat is .045". I test operation by alternately sucking and blowing on the rubber hose running from the crankcase breather to air intake. Should suck without restriction, quickly transition to considerable restriction with a little leakage on blowing.

Walt Conner