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· Registered
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Discussion Starter · #1 ·
I am purchasing a piece of commercial equipment spec'd out to mow a 30 degree slope ***. It has a B&S Vanguard 993 cc, 37 HP V-Twin engine. I am curious why the literature cautions a maximum continuous mow time of 10 minutes mowing a 30 degree slope? The time increases to 20 minutes on a 20 degree slope.

My first thought for this caution is something oil related. But it has an oil pump, oil cooler and the sump is centrally located. Any thoughts? related engine specs are:
  • Oil cooler reduces oil temperature, improves lubrication and extends oil change intervals
  • Dura-Bore cast iron cylinder sleeve assures long engine life and oil control
  • Convenient oil drain locations for trouble-free maintenance
  • Full-pressure lubrication with spin-on oil filter cleans oil and protects engine components to ensure maximum lubrication and long life
  • Centrally located oil pump and pick up for faster priming allows for a higher angle of operation
  • Pressure-regulated full flow oil filtration keeps oil clean longer, extends time between oil changes and improves bearing life
  • Oil dipstick provides easy access to check oil levels

· Premium Member
6,078 Posts
In addition to the danger of the oil pickup losing flow, you also run the risk of having the oil in the pan contact rotating assemblies, which will whip it into a useless froth very quickly.

Also welcome to MTF, glad to have you here.

· Super Moderator
24,225 Posts
Welcome to MTF!

Also, the oil drain back passages do not function quite as well with an engine tipped 20 - 30° to one side when side sloping a hill. There is a risk of flooding the valve train of the low side cylinder.

When running up and down slopes, besides oil drain back from the cylinder heads. there is also the fact that the low end of the crank is actually submerged putting a bit of pressure on the crankshaft seal which is not really designed to withstand pressure.

The time limitation at those angles is to ensure that the associated factors mentioned do not create a problem.
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