I have a troy built with a 21 hp briggs and stratten intek v-twin. i was cutting grass and it started running rough and made a couple of clanging noises and finely quit. and will not start. it will turn over. and doesnt make any unusual noises while its turning over. and it doesnt leak oil. any suggestions

SOURCE: Stratton Briggs Stratton Intek V - Twin Engine 21

The oil is contaminated with water. Change oil and filter, if it has one.

SOURCE: Briggs & Stratton Briggs Stratton Intek V -

these are common for doing this ,if you dont want to pull it down and hone the cyl. then i would use a heavier oil say 20w/50and that will probabley solve your problem

SOURCE: 21hp intek v-twin runs only with choke on full

You are not getting enough fuel.... by choking it you are enriching the mixture with less air , more fuel.Some where in the fuel system or carbureator something is still plugged.Or the mixture screw is too far in.

SOURCE: Briggs and Stratton Intek V

Misfiring could be caused by simple things like fouled or worn out sparkplugs or an ignition system that is slightly faulty or Fuel problems such as dirty or stale fuel or clogged filter causing a leam mixture. Some B & S motors have an switch that cuts the Ignition if the oil pressure or oil level is low.
Another cause could be the Valve clearances are out of adjustment.
Armed with your Engine Number, visit the B & S Website for comprehensive information and specifications as well as a good FAQ listing.

Kelly

• 3740 Answers
• Posted on Apr 13, 2011

SOURCE: Briggs & Stratton Intek 20hp

Hi and welcome tgo FixYa, I am Kelly.
Seems odd that it just came up missing but yes you can install new parts. The manual you will need is here:
http://www.mymowerparts.com/pdf/Briggs_&_Stratton_Service_and_Repair_Manuals_Spec_Charts/273521%20Twin%20Cylinder%20OHV%20BRIGGS%20&%20STRATTON.pdf

The governor data is in section 4 of the pdf file starting on page 34.

I used this model number when searching for your manual:
44K777 - 0027 - E1

Now keep in mind there is also an adjustment that you must do on the governor. Do the
Static Governor Adjustment and Dynamic adjustments on page 100 and 101 of the manual.

Thanks for choosing FixYa,
Kelly