Small Engines (Lawn Mowers, etc.): Wheelhorse 724-z w/Onan engine problem, blown head gasket, high grass

Question
Onan ser#f883390492
model t260g ga024/4404f
26hp
Hello.
My mower seems to run fine but the switch to turn on the deck went out. I replaced it and now when I turn on the deck and start to mow, the throttle goes down alot and it bogs down real easy. I have to cut real slow. It acts as if it is cutting way too high grass etc. and is laboring. Every couple minutes the mower throttles back up and cuts real good for a minute then goes back to bogging down.
I also noticed that when it throttles back up that(as if out of heavy grass) that a little black oil came out of exhaust. There was also a small amount of white smoke when it did this. Any help would be greatly appreciated.
I'll be out of luck if this mower breaks down for good!! I love it! Please help!! Thanks in advance.

Answer
Hello Chris:

From your Description, it Sounds like a Blown Head Gasket between the Compression Chamber and the Valve Stem Galley. I am Trying to Locate a Breakdown for you to View Online. If I Locate a Breakdown, I will Send the Addy to you in a Follow Up Answer. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John