Toro Lawn Tractor - B&S Engine Problem
We have an 11 year old Toro Wheelhorse lawn tractor that has seen some heavy use. You all helped us out with a problem a few years ago, so we're back with this year's problem. Thanks in advance for your help!
Here's the details (hubby wrote this part):
Toro Wheelhorse lawn tractor, with 16hp Briggs OHV engine, model
It had been very hard to start all winter, so I finally got around to
adjusting the valves. They were a long way from spec, but looked
otherwise healthy. I replaced the spark plug and set the carb a little
leaner, as the old plug looked like the engine had been running overly
rich. I also checked the air filters, oil level, etc.
It started really easily after I put it all back together and ran much
better than before. I worked it quite hard for three days, hauling a
small trailer with a bunch of pretty heavy loads up hill. All was good
until partway up hill, it suddenly blew a cloud of smoke and the
engine sound changed to a very harsh rattling noise. I stopped
immediately and saw that it had blown the breather tube off the carb
and spewed a bunch of oil from it. I reconnected the tube and started
it back up again. It started fine, but the engine still sounded very
harsh, so I shut it off and pushed it back home.
Nervously tried starting it again - it spins fine, but doesn't start
up. I don't see anything obviously wrong, except for the mess from the
oil. Breather tube looks unkinked. Spark plug looks OK, but had a
light coating of oil. Engine oil level has dropped a little, but is
still nicely above the minimum fill level. No sign of any oil dripping
from the engine.
Any ideas what to look at first?