Professional Series™ (Single Cylinder)

15.50-19.00 Gross Horsepower

World-class performance – time after time. With commercial-grade power, easy starting and quiet operation, the Professional Series riding mower engine delivers great results for your toughest jobs. And it keeps delivering, because this mower engine is built to last with our exclusive Advanced Debris Management System, chrome-plated exhaust valves and other durable features.

  • Single cylinder and V-twin engines offer the best of both worlds: world-class endurance and power.

  • Advanced Debris Lawn Mower Filter
    Advanced Debris Management System

    Keeps your engine clean by deflecting most debris like micro grass clippings & lawn debris and filtering the rest.

  • Dura-Bore™ Cast Iron Sleeve

    Withstands wear and abuse.

  • Full Pressure Lube System

    Cooler operation and longer life.

  • Advanced Formula Fuel Treatment and Stabilizer | Briggs and Stratton

    Safeguards engines against ethanol damage and maintains fuel stability for up to 3 years.

    See the full benefits of Advanced Formula Fuel Treatment & Stabilizer.

  • Avoid Lawn Mower Engine Damage

    Look Before you pump fuel into your lawn mower and help avoid engine damage. Do not use any fuel containing greater than 10 percent ethanol (E10) in the engine on your outdoor power equipment.

  • Briggs & Stratton OHV Engine Design
    Overhead Valve (OHV) Engine Design

    OHV engines run cooler and cleaner for better fuel economy and longer engine life.

  • Tool-less Air Cleaner Cover

    Easy access for filter changes

  • Have a question? Search our FAQs to find answers related to model specifications, routine maintenance, repair or troubleshooting. Search FAQs »

  • Find genuine Briggs & Stratton repair and/or maintenance parts for your engine or outdoor power equipment to ensure future performance. Purchase Parts »

HP** (gross) 15.50
Engine Displacement (cc) 500
Number of Cylinders Single
Engine Configuration Vertical Shaft
Engine Technology OHV
Length (in) 18.9
Width (in) 16.2
Height (in) 12.9
Weight (lbs) 77
Bore (in) 3.56
Stroke (in) 3.06
Engine Fuel Gasoline
Fuel Tank Capacity (gallons) N/A
Lubrication System Full Pressure Lubrication
Oil Capacity (oz) 48
Oil Filter Premium
Starter Electric Start
Air Filter Dual Element Cartridge with Advanced Debris Management
Muffler Optional
Fuel Shutoff Valve Optional
Certified Power Rating

*All power levels are stated gross horsepower at 3600 rpm per SAE J1940 as rated by Briggs & Stratton.

*All power levels are stated gross torque at 2600 rpm per SAE J1940 as rated by Briggs & Stratton.

Professional Series™ (Single Cylinder) is rated 2.0 out of 5 by 12.
Rated 1 out of 5 by from 21 hp engine This engine has just over 200 hrs. on it. It is on a John Deere mower and the engine started using oil at least a 400 mls per hour of cutting. Dealer adjusted valves, cleaned carb and it still clogs the plug and dies. Have to have 2-3 plus at a time to get my yard cut. Now the dealer tells me they have changed this engine to a 19 hp. The engine should last longer than 200 hrs. The unit is only 5 years old
Date published: 2015-09-02
Rated 1 out of 5 by from Best Boat anchor I have ever owned!! Ok time for me to pitch my 2 cents to the pile, this engine is junk. I have been repairing and servicing these boat anchors for almost 10 years now, Not once have I ever said "Wow this is an awesome engine!" The head gaskets blow up, the push rods are junk, the cam-lobes magically disappear, and if you get 100 hours out of it it's a miracle!The engines start decent when the valves are adjusted. Decent power though I will give it that but otherwise a garbage motor!This year alone I have replaced almost 10 of these engines so far, I have a pallet of them. All blown. All making amazing boat anchors! Avoid this engine if you can!
Date published: 2015-05-22
Rated 2 out of 5 by from Dead Briggs 21 hp I purchased this engine 2 years ago and have been quite happy----but----at 153 hours the engine started to burn oil. A lot of oil. Finally the spark plug fouled and it quit. The oil was saturated with gas. Changed plug---oil and filter and within 5 minutes the smoking engine gave up the ghost. I have replaced it with a new 20hp Briggs and am hoping for the best.
Date published: 2015-05-13
Rated 1 out of 5 by from Briggs & Stratton Intek Vertical OHV Engine faulty I do not want to seem to be over-reacting, but I feel that there is a major flaw in the Briggs & Stratton Intek Vertical OHV Engine. I have used this engine exactly three times, and upon the fourth, it would not start. Inspection revealed gas in the oil, excessive fuel in the spark plug chamber, and an inability to start. This engine replaced the original engine in my craftsman mower, which had previously blown up while I was mowing. I have since taken it to an authorized service dealer, who told me that he could not find anything wrong with the mower. Furthermore, he consulted with a Briggs and Stratton representative, who also could not find anything wrong. Their solution was to flush my fuel and oil system, then remove my fuel pump from the mower, thus rendering it a gravity-fed fuel system. Now my mower will start; however, it will mow for only two minutes then dies, sputtering in it's death throes. I am so extremely dissatisfied with this engine, as well as the previous Briggs and Stratton 19.5 HP engine. I cannot caution future buyers enough in regards to this product. I believe that this engine was manufactured to be eco-friendly and pleasurable to ride, but it is NOT A DEPENDABLE lawnmower engine.
Date published: 2012-05-05
Rated 1 out of 5 by from This is the worst engine I ever owned The engine came on a Craftsman mower. Craftsman is the only brand mower I have owned and have owned 4 including this one. Never any problems with engines. The engine has not been abused in anyway and did not last 100 hours. Please don't waste your money on the 21 hp briggs.
Date published: 2012-08-28
Rated 1 out of 5 by from this engine has all the power I needed in a lawn mower,but it has started using oil I purchased this craftsman lawn mower for my large estate size yard and it is powerful enough for what I cut, however it has started using oil, The engine has 326 hrs and I have maintained according to the manual and more, after each use I blow the engine clean with a yard blower, including taking out the carb filter and blowing it off. My lawn mower is a 2006 model and still looks like new. However it has started smoking and burning oil, avg about 1 pint per hour of use. This the first Briggs that has ever given me this probem and I am disapointed. I would not recomend to my freinds. I am going to rebuild or repower because of oil consumption.
Date published: 2012-11-01
Rated 1 out of 5 by from Poor Engine that did not last. I bought the mower a little over 2 years ago. Cam shaft had to be replaced. Should have been under warranty. Took it to their authorized repair people and was charged over 400 dollars to get it fixed. It was a poor fix because the engine started smoking the first time out. Talked to some people struggling with the English language and got nowhere. Forced to buy a new 19 hp motor. Maybe the 21's were so bad they stopped selling the. Very disappointed in this B&G.
Date published: 2015-08-02
Rated 4 out of 5 by from Good engine 24HP, nice mower craftsman professional The mower and engine perform well, my only problem is with the starting on the engine. Second season, I had Sears fix a hard starting problem which happened to be choke related, minor adjustment and started fine. Two years after same problem has occurred, I bought the manual, but it does not detail the adjustment of the accelerator/choke assembly on this engine. Only separate choke cable and separate accelerator settings. I have contacted Briggs and Stratton with no answer. I have since adjusted it myself, although it starts fine now, I would still like to have the procedure for adjustment detailed by B&S. Again I purchased the manual and this procedure is not defined. I have a very good mechanical background and capable of repairing large and small engines.
Date published: 2011-11-01
  • 2015-10-06T06:02CST
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