450 Series™

The 450 Series™ is an entry-level family of engines. Compact, lightweight, and simple to operate, these engines provide dependable power at an exceptional value.

  • Oil-Foam Air Cleaner

    Helps keep your engine clean.

  • Prime N Pull
    Prime 'N Pull™ E-Z Starting System

    Push the primer bulb three times and go

  • Lo-Tone™ Muffler

    Cuts quieter.

  • 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 »

Torque* 4.5
Engine Displacement (cc) 148
Number of Cylinders Single
Engine Configuration Vertical Shaft
Engine Technology L-Head
Length (in) 12.8
Width (in) 11.5
Height (in) 9.5
Weight (lbs) 19.8
Bore (in) 2.56
Stroke (in) 1.75
Engine Fuel Gasoline
Fuel Tank Capacity (gallons) 0.225
Lubrication System Dura-Lube Splash Lubrication
Oil Capacity (oz) 20
Oil Filter No
Starter Prime 'N Pull
Air Filter Oil-Foam
Muffler Lo-Tone or Super Lo-Tone
Fuel Shutoff Valve NA
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.

450 Series™ is rated 3.1176 out of 5 by 17.
Rated 2 out of 5 by from Changing Engine Oil-Bad News My model # 9T5021428B110034 Will not come up as a valid engine onThe Briggs & Stratton Web Site. The user manual I have for the engine shows two possible oil drain locations & neither one exists. I called the Southern States Store where I bought it & was told that as far as they knew the oil had to drained by emptying the gas tank & turning the mower upside down to drain the oil from the oil fill plug. I also called & talked with a B&S representative & he confirmed that the oil could only be drained from the fill plug. I have used B&S engines for years & this is the first I have owned that did not have a bottom oil drain plug. In my opinion this is a very poor design from a maintenance point. Unless thispoor design is corrected this will be my last B&S engine. Also had trouble 1st month would not start & had to take back to dealer for repair & my grass just kept growing.
Date published: 2012-03-15
Rated 1 out of 5 by from big problems starting I bought a mower with a B&S 450 and the shop had to replace it as it ran for only a few seconds after priming. The next one had exactly the same problem! The next one after that actually started - which was major progress - but seemed sluggish. Now, after a mild winter, it won't start - same problem as the first two. Apparently B&S - even new - can come with significant carburettor diaphragm problems. I'd rather scrap it at this stage than go back to that poor shop again!
Date published: 2012-03-15
Rated 3 out of 5 by from wont start all the time went well when i first got it and its just gone down hill .dont mind briggs and strattions but all in all this model is no good
Date published: 2011-11-19
Rated 1 out of 5 by from NOT a good buy We brought this mower in good faith, we have managed to start it once in the three weeks we have had it, our neighbour who works out, in the gym. can not start it and hes a young man of 40 yrs old, we now have a mower we can not use this is not any good to usHELP is need here
Date published: 2012-04-12
Rated 5 out of 5 by from love these small briggs and stratton mower engines these are amongst the best mower engines available, put fresh gas in ,and check your oil. perform routine maintenance, and these engines will last and last. powerful and dependable, i wish the lawn mower manufacturers would use briggs and stratton instead of those chinese honda-knock-offs
Date published: 2011-10-31
Rated 1 out of 5 by from Just doesn't cut it. The lawn, that is. We bought this mower last summer and had a lot of trouble starting it. It would roar to life, but then die after one or two seconds. Eventually, by wedging an object between the throttle cable and the push handle to pull the cable tighter we got it to start, but it ran very roughly. This year it won't start at all, with the same symptoms of coming quickly to life and then stopping almost immediately. I gather from the other comments that I'm not alone. All my other experiences with Briggs and Stratton engines have been positive, so I'm quite angry that we seem to have purchased a lemon.P.S. Your system won't accept our model number either, so I can't download a manual. 9S502-0520-B1
Date published: 2012-05-15
Rated 5 out of 5 by from I like Briggs and Stratton engines because they are the most dependable and easiest to diagnose and repair. I'm 77 and have always mowed my own lawn and mowers with Briggs and Stratton engines always last longer than ones I have had with other engine makes. When I don't hit a stump and bend the shaft the Briggs and Stratton engine always out lasts the frames. If I keep the air filter clean and don't snag the carburator springs and stretch them, they always keep running like new. You build the best engines.
Date published: 2011-10-31
Rated 5 out of 5 by from 450 series engine i have a plastic mcculoch with one of these engines in hence a golf ball has cracked the flimsy deck on it brought it used for 30 quid last year it started but was hunting and cutting out when it got warm i looked on forums and worked out it was the diaphragm it cost me 5 quid got a new plug changed the oil cleaned the filter and its never failed me i changed the oil last week and it continues on howether i just obtained an old m4 mountfield mower with the older 350 series 4 cycle b&s i need to get round to repairing if not il put my 450 series engine on the aluminium frame so i have a mower 4 life can anyone tell me would i be better using the 4 cycle engine or the 450 series as far as i know i think the 4 cycle was built for life and the throttle bodies are different should be able to pull it off
Date published: 2012-06-13
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