It is a solid engine these days but headed for the scrap heap.

The Quantum Power began in the late 80's and went through a period of trouble with the valves.

The fuel tanks have also gone through troubles and still have some. Initially the problem was with the shut off valve which they originally had from the factory. After several failed attempts to correc they just eliminated the valve. But ever since they have had problems with seam seprations causing leaks. Still do. They also now have some plain old tank cracks on the inside corners.

The engine valve problems have ong since been corrected.
The tanks with fuel shut off valve troubles were placed on a safety recall. Still good for those who have one.
The seam and crack leaks although not on a safety recall will still be warrantied as long as the failure is not caused by obvious damage.

The engine has been the mainstay for the Briggs rotory mower line up for years and except for the occasional continueing saga of fuel tank failures[which by the way is also seen on Inteks using the same tank]the Quantum Power has been an excellent engine.

It is on the way out though due to emission regs. It already is history in Kalifornia and as soon as EPA standards meet Kalifornia's CARB regs this great old flathead will be gone altogether. EPA regs are currently slated to come in line with CARB in 2010 but there is some talk of bumping it up the end of this [07] year. Time will tell.

Great history! Thanks for posting it. I am a bit disappointed they will be eliminating it. I suppose this will be the last one I purchase. I hope they make a follow-up as good as this one.

Good engine. Many stories such as your all over the place. Briggs makes some workhorse engines, and have been doing this for a long long time.

I have owned a Troy-Bilt mulching mower with a 4 HP Quantum engine for more than EIGHTEEN YEARS. I bought it new in 1989. The engine still runs perfectly and starts on the first pull. I have never done ANY maintenance other than change the oil and occasionally the spark plug and filters. Right now I mow with a tractor so I just use the Troy-Bilt for the trim but use it every year for the past 18 years. The mower itself is built like a tank too, the power coat paint finish is still all good. Not flaking at all. It was the like the Bolens mower with front wheel drive.

I agree - i have 15 lawntractors with briggs motors aging from 15-20 years old still running good and solid on original internal parts. These havent been babied motors either, all were abused non runners when purchased ( dirty oil, no oil, left outside to rot, ect). The HP ranges are from 5HP singles to 18.5HP twin flatheads. Impressive motors, with some more TLC and alot of oil changes im hoping for another 20 years or more from them.
Kidd

I was the original poster of this thread. It's 2026, and still have this mower and engine. Still starts on first pull.