Briggs and Stratton Vertical 17.5 HP 500cc INTEK Engine 9amp 1" x 3-5/32" #31R977-0054
Condition: New
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Availability:
In Stock.
Arrives
Thursday, Sep 24
Features
- Cast iron cylinder sleeve and dual element air filter for extended engine life
- Patented linear balancing system provides smoother performance
- 9 amp/electric start only
- 1" x 3-5/32" shaft, tapped 7/16" with 1/4" keyway
- Common riding mower replacement engine
Description
This genuine 500cc Briggs & Stratton single cylinder engine offers dependable power for your equipment needs. With a power rating of 17.5 horsepower, this engine features a premium Dual Clean air filtration system, electric starter, and maintenance-free Magnetron electronic ignition. With a manufacturer limited warranty of 2 years consumer use / 1 year commercial use, Briggs & Stratton provides power that you can trust. This engine includes a Dura-Bore cast iron cylinder sleeve for extended life. This engine includes a fuel pump. This engine includes an oil filter. This engine includes a 9 amp charging system.
Product Dimensions: 19 x 4 x 4 inches
Item Weight: 0.01 ounces
Manufacturer: Briggs and Stratton
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Thursday, Sep 24
This item is non-returnable:
Non-returnable. Transportation of this item is subject to hazardous materials regulation
View our full returns policy here.
Non-returnable. Transportation of this item is subject to hazardous materials regulation
View our full returns policy here.
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Top Amazon Reviews
The engine runs great. I placed it on a 2006 Yard Machine. The wiring for the lights is still disconnected. Not sure what to do with that. You will need to solder or use a connector kit with crimper. I modified the wiring plug to accept the new wires. The engine is heavy so have 2 people lift. Use an impact to remove belt drive shaft bolt. Very pleased. No sense in spending over 2k for a new rider. Great value. Great fit. Just take your time starting the bolts to make their own threads. Add gas and yell fire in the hole!
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Reviewed in the United States on August 30, 2026 by Imdonetalkin
Very nice replacement engine on the toro zero turn mower
Reviewed in the United States on July 6, 2026 by larry Burns
Simple to install with no issues
Reviewed in the United States on September 4, 2026 by Terry Bruner
This is a first time I have installed a replacement engine for my John Deere lawn tractor. It took about 3.5 hrs to remove the old engine and install the new engine. It was a direct replacement, but a catch is the old motor was labeled as 19.5 hp and the new one was listed as 17.5. This was explained that John Deere cheated a little when they did there testing at the factory. I can say that the new one was a direct replacement and once installed I could not see any difference between the old one and the new engine. You will have to remove some of the old wiring from the old engine to the new one, so take your time and document the wiring from old to new. The 4 mounting bolts will also need to be tapped. This was a pain as you had to be under the mower for an extended period of time ensuring that the new treads are cut properly with the self-tapping bolts. Make sure you purchase the oil recommended oil as there is no oil shipped with the new engine. The performance of the new engine appears to be great and I could not tell any difference in between the two when mowing. Overall a great experience, and very fast shipping.
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Reviewed in the United States on April 20, 2024 by Brian
After 22 years the original 18hp B&S engine on my old Troy-bill lawn tractor seized up when the throttle came apart and the screws got sucked into the cylinder. The mower has been serviced and garage kept over the years and is in good shape otherwise, so I didn’t want to scrap it and buy a new mower. I decided to replace the engine with this one after reading the overly positive reviews and received shipment in two days. Even though most say you can get the mounting bolts to work without cutting threads in the mounting holes on the aluminum block, I tapped mine anyway. This engine fit perfectly with the only issue being the vacuum line behind the engine going to the fuel pump is wedged against the fuel tank, but works just fine. There is an extra wire (orange) from the original engine coming from the alternator that is not used in this new engine, otherwise all of the wires are the same color and function. I hooked them up to the old engine side wiring harness connector leaving the orange harness wire cut and capped off. Added oil to the engine, hooked up the gas line and it cranked right up. I’ve mowed twice with it so far and it is every bit as powerful as the original 18 hp engine was and runs smooth. I have a yard with some steep slopes and this engine does not even slow down going up steep grades. As I discovered later, the orange alternator wire on the old engine powered the mower headlights. But I pulled power from the single alternator wire to the light circuit at the ignition switch and the headlights are working again. Time will tell if this engine will be as good as the old one, but for now I feel good about this purchase.
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Reviewed in the United States on May 5, 2025 by J. Baxter
After doing a ton of research I found this engine would fit in the same spot as my old 31r907. This model, the 31r977, featured some desirable upgrades like an oil filter and a fuel pump. It was easy to install in the same spot as my old engine. As others have said, do not despair about there not being threading in the mounting holes, your old bolts will make the threads for you. Just start the bolts and turn slowly with a socket wrench. There was some minor wiring I needed to do between the two. What I ended up doing was comparing the old harness to the new one. I de-pinned some of the connectors on the new harness and used the old harness clip to wire into the rest of the lawnmower. Take your time, make sure the wires from the new harness fit into the same spot the old wires did in the old clip, and it'll work perfectly. Something I didn't realize was the old crank bolt is on TIGHT. Be prepared to fight with a bit both getting it on and getting it off. On my 31r907 the torque spec was about 100ft-lbs. This engine does NOT come with oil, be sure to add engine oil before operation. There is a little bit of oil in the crank case probably just for testing. 5 stars, anyone with a bit of mechanical knowledge could swap one of these engines. Very easy as far as motors go.
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Reviewed in the United States on May 30, 2024 by Amazon Customer
I repowered my John Deere D100 series with this product. This does not come with the new exhaust gasket, so make sure you order it as well. The holes on the mount are self tapping, so i used WD40 and they screwed right in with my impact wrench. I also had to replace my solenoid, and figure the wiring out, which did require splicing with this swap. Grey-Grey Blck-Black Red-Orange to existing harness. Took me 2 hours to do the swap. Cranked first turn once I swapped the solenoid. Ran great on the first cut. Simpler than I had expected.
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Reviewed in the United States on July 29, 2026 by frank a burris
This Revived my 12 year old D105 mower. Would highly recommend
Reviewed in the United States on April 24, 2026 by GC