Free Shipping and No Hassle Returns
Free Shipping
We offer free shipping on orders over $199.*
No Hassle Returns
Don’t like it? Send it back. It’s that simple.*
Same Day Shipping
Most orders ship same day if placed by 5PM EST (M-F)
*Restrictions Apply. See Details »
Model#: BGSN31P777-3202-G5

What are the different product conditions?

Brand new items;Full manufacturer warranty available
Manufacturer inspected, repaired and tested items; CPO 60 day money back guarantee
Open Box
New or Recon items with possible minor cosmetic damage; CPO 60 day money back guarantee
Returned items inspected, repaired and tested by CPO technicians; CPO 60 day money back guarantee

Briggs & Stratton 31P777-3202-G5 500cc Intek Series Engine with 1 in. Tapped 7/16 - 20 Keyway Crankshaft (CARB)

  • Briggs & Stratton 31P777-3202-G5 500cc Intek Series Engine with 1 in. Tapped 7/16 - 20 Keyway Crankshaft (CARB)
Sale Price:
You Save
Free Shipping
(continental U.S.)
Ships in 2-3 business days


Briggs & Stratton's powerful Intek Series engines deliver unmatched reliability along with superior performance and durability. Featuring XRD technology, the Intek Series features enhanced durability and overall performance due to the consolidation of dozens of improvements.
  • Advanced debris management with dual-sealing cartridge style air filter provides the maximum protection to extend engine life
  • AVS anti-vibration system provides linear balancing to eliminate side motion to reduce vibration and smoothen operation
  • Dura-Bore cast iron cylinder sleeve withstands more wear and abuse while providing improved oil control
  • DuraLube splash lubrication system offers a gear driven system that continuously supplies oil to all internal parts
  • Dual-Clean air cleaner pleated paper filters with foam pre-cleaner maximizes engine life
  • Maintenance-free Magnetron electronic ignition for quick and dependable starting
  • Model Specific Features: Pulse fuel pump, Choke-A-Matic choke, 12V Gear Drive start with 9 amp DC alternator, oil pump with filter and dipstick oil system
  • Please Note: Fuel tank omitted from this model
  • 500cc Intek Series Engine w/ 1 in. Tapped 7/16-20 Keyway Crankshaft - 31P777-3202-G5


Series: Intek
Length: 23.8 in.
Width: 21.2 in.
Height: 20.3 in.
Weight: 77 lbs.
Application: Lawn Mowers, Riding Mowers, Tow-Behind Mowers
Carburetor: Float-Feed
Controls: Remote
Cooling System: Air
Crankshaft Diameter: 1 in.
Crankshaft Length (Sump Face to Crankshaft End): 3-5/32 in.
Crankshaft Model Number: 796948
Crankshaft Tapping Size: 7/16-in - 20
Crankshaft Type: Keyway
Cylinder Bore: 3.56-in (90.5mm)
Cylinder Stroke Length: 3.06-in (77.6mm)
Engine Configuration: Vertical
Engine Displacement: 500cc
Engine Technology: OHV
Fuel Type: Gas
Governor: Mechanical
Governor Max. Speed (RPM): 3,300
Horsepower: 18.5
Lubrication System: Pressure Lube
Number of Cylinders: 1
Oil Capacity: 48 oz.
Power Type: Gas
Starter: Recoil



2.5 / 5.0
64 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
No, I would not recommend this to a friend (21)
Yes, I would recommend this to a friend (11)
Powerful (2)
No, I would not recommend this to a friend
This product is not reliable
I have the 21hp engine and it began to burn oil and blow blue smoke. The engine has only 3 seasons of just cutting grass. I was concerned that the rings were bad but afer reading the reviews I find that it's the head gasket. I would hope that the BnS engineers would come up with a better service part to fix the bad design but I doubt it since it lasted through the warranty period. I would not recommend this engine until they fix the flaw.It would also be good PR to publish a response to this issue on their web site.
May 17, 2012
No, I would not recommend this to a friend
I have owned this for just over 2 years, and it is burning oil!! Just out of warranty, that figures. I contacted Briggs about warranty, no answer. I will never get another Briggs engine in any power equipment...unless I plan to sell it after one year!!
October 31, 2011
No, I would not recommend this to a friend
failed head gasket
the head gasket on my john deere la 125 failed after 26 months which put me 2 months past my warranty. now having read in your answer and questions that seem to be a regular problem with your product. i have ordered a new one from your online sight. i had always wanted a john deere with a briggs stratton motor and i was proud of this purchase it was a lot of money for me now i cant believe a company woud sale a product that is faulty. you can look at the gasket and see the weak spot where it failed the gap is to far apart of the bolt holes thanx for letting me vent
May 6, 2012
No, I would not recommend this to a friend
Earlier model has head gasket problem
I hope that the improvements in the "XRD" system include a redesigned head gasket system. My 6 year old engine (31P777 series) has required a new head gasket twice so far. The gasket fails in the area between the cylinder wall and the oil galley, allowing exhaust to contaminate the oil and oil vapor to be drawn into the cylinder. The original gasket managed to hold up long enough to be out of the two year warranty. I noticed that the latest gasket has a new part number; hopefully it has been redesigned. I have found that older B&S engines seem to run forever with no repairs; my oldest (23 years) is in a push mower.
November 2, 2011
No, I would not recommend this to a friend
After 2 years of light use, the engine is hard to start andblows massive clouds of white smoke.
March 29, 2016
Yes, I would recommend this to a friend
great engine
I'm on my seventh season with this engine. I use it year around, mowing and plowing snow with my John Deere tractor. I've never had a bit of trouble with this engine. It starts right up in the coldest weather as well as the hottest weather. Currently I have over 300 trouble free hours.
June 2, 2012
Yes, I would recommend this to a friend
Numerous design flaws
As a power mechanic I've had the opportunity to repair / rebuild many of these particular model engines. The issues I've seen in this particular engine are, Poor head gasket design. Found many engines blow the head gasket into the valve push rod area over pressurizing the crankcase and causing engine to smoke excessively. Leaky Carbs. Can't count how many times I needed to install new float needle valves also install manual shut-off vales for good measure. Poor cam shaft. Found a few engines that worn the exhaust lobe of the cam shaft in turn not allowing the exhaust valve to open fully. Leaky valve cover gaskets. Valve covers leak, in turn dripping oil onto the muffler and causing engine to smoke.
November 1, 2011
No, I would not recommend this to a friend
very disappointed
Bought the 21 hp Intek in a John Deere tractor for my son 4 years ago. John Deere and Briggs and Stratton, all bullet proof products right. From the start oil consumption was a problem. The mower mfger says these engines need a lot of break in time, don't worry. As much as 50 hours. Guess what, 50 hours equalled the warranty period, It got to half a quart per mowing, then fouled spark plugs. By the beginning of the 4th year oil is blowing out the fuel pump vent. Contact B&S, they say to bring it to an authorized dealer. If it looks like a factory problem maybe an adjustment can be made. No such luck. Full price for repair and I absorb the transport charges. Gasket failed in the longest run of unbolted length, just like some of the other posts. Not the B&S I thought it was.
May 22, 2012
No, I would not recommend this to a friend
leaked and burned oil
I purchased a Craftsman lawn tractor in 2008 with this engine. Within the first 3 months it started leaking oil. I thought it was just the quick release oil drain, so I replaced it with pipe. Still leaked and got worse with time. I turn it in for warranty repair end of the 2 year mark. They had to replace the lower seal. No more oil on the floor, but I still needed to add oil after every mowing - not sure when it started burning the oil. But was not able to take it back for warranty due to over the 2 year mark. I kept adding oil for each mower and the use continuously got worse and started fouling the plug in the 3rd season. This is the forth season but because of the drought we haven't needed to mow, until last night. Now it's blow so much blue smoke that it's hard to mow at times. I thought I maintained my equipment well, but this engine didn't hold up. The mower is still good but the engine is shot. Not sure if I'll replace the engine as I don't was another experience like this one. I wish I knew of another brand that would fit the mower. I wonder if Briggs would provide a replacement or at least let me purchase another engine at cost.
August 29, 2012
Yes, I would recommend this to a friend
Reliable engine
I have had this engine on a John Deere D110 tractor for over three months now,and I have not had any problems with it at all. It starts right up and has more than enough power for my needs. For a single cylinder engine it is fairly quiet and I believe the OHV has alot to do with that. It is also very easy on gas,...have mowed several times and still sitting at the "full" mark on the gas gauge,if not just very slightly below it.
July 31, 2012

Questions & Answers

Start typing your question and we'll check if it was already asked and answered. Learn More
No questions have been asked about this item. Be the first!