21 Horsepower Briggs Engine- Bad Smoke

My daughter has a zero turn mower, Hustler, with 21 HP Briggs engine. It was running
perfectly and started to smoke terribly. Still runs OK. It has the fuel pomp on the side of
the engine (hockey Puck style) which evidently pumps in relation to the crankcase pressure
by the downstroke of the piston. It is sucking up oil from the crankcase and leaking out
the oil through the fuel pump vent and pumping some into the fuel line. We got a new fuel
pump, but still has the problem. Is this a failure of the crankcase ventilation system, or
would I suspect other problems? I am currently 450 miles away and would appreciate any help or ideas. Many Thanks for your input.
 
I have a Briggs 15hp single cylinder on a Ariens zero turn that was doing about the same thing. It was the neighbors and he parked it out back. I got it from him and discovered a blown head gasket, which seemed to be a common problem. Replaced that 3 years ago and its fine. Guessing the 21hp is a twin, not sure if they do the same thing or not.
 
I used to work at the local golf course doing the maintenance and repair work and we had some trouble with the Briggs V-twins like you described. It was usually the head gasket blowing where the valve push rod cavity is. Clean and check the head and block surface areas for being straight with a good straight edge and resurface if over .003 of an inch and then be sure you torque the heads exactly like the book says with a torque wrench and not by feel.
 
Did you check for gas in the oil after changing fuel pump? Crankcase could be way over full and pushing oil and gas out through breather and burning it.
 
I am also voting for gas in the oil causing it to overfill the crankcase.

Daughter of mine had a similar issue and I traced it to a bad shutoff solenoid on the bottom of the carb. Not a very expensive part but very aggravating because of the potential damage it can cause by running with diluted oil.

OEM B&S part on eBay should be in the $20.00 range. Try to get OEM if possible. Had a knockoff fail almost immediately.
 

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