The Briggs OHV mower engine was introduced about 10 years ago. It features the same displacement, bore & stroke as the Quantum series engine. The engine is several pounds heavier than the Quantum series.The carburetor is easy to service - but not quite as easy as the Quantum.

The throttle plate does not have a stop screw for the idle position as the engine is designed for governed slow speed. The throttle plate wedged in the closed position on the engine I have - even tho the throttle control was set for full speed. This created some hard starts until I discovered what was happening. A boss was provided so I installed my own throttle stop screw. At my 7300 foot altitude, the compression release reduces the starting compression to about 30 - 40 psi. Normally, the engine started ok. Power was very good. The cast iron sleeve is a good feature.

The mower deck is similar to the Snapper design. Previously the comments on this board seemed to favor the Toro Super Recyler as the best mulcher mower. The Snapper design was good for bagging (the model in the link you provided is set up for mulching). Rear drive is a good feature. The caster wheel design adds a few more pounds to the overall weight of this mower.

Since the mower was returned, is there a warranty? Does John Deere honor the warranty on returned equipment? $300 is probably a good price provided you like the mower.

My opinion - Before buying, look at the JS-20 for the following reasons. The engine is the older flat head design and weighs less. This Quantum series engine is equipped with the "ready start" system that (in my opinion) is easier to start than any other brand engine including the OHV Briggs on the JS40 The mower has the regular front wheels - not the caster style.

Here is a Gee Whiz point. I don't think any of the other mower manufacturers use the cast iron sleeve Briggs as the aluminum version is cheaper. Most of the Honda mowers use the aluminum bore Honda engine. I believe all Kawasaki engines are equipped with cast iron sleeves.

Well, if you want to compare engines, how about power!
JS20- 6.75 ft-lb torque
JS40- 8.75 ft-lb torque
The latter also has the Peak of its "torque curve" around 2800 RPM vs about 2400 RPM for the flathead. Much closer to actual mowing speed.
If you plan on mulching, I think it's a no brainer.

This seems to be a common problem with the JS40. The Lowe's I bought mine from also had a used one for sale with this problem repaired. I got to use my brand new one for 20 minutes before something broke and the self-propelled quit working. DO NOT BUY unless you get the full warranty and have a dealer that can service it nearby. Good luck.

I BOUGHT MINE AT LOWES. IT HAD A STICK CAUGHT IN THE BELT DURING TO THE FIRST 2MONTH, THE LOCAL DEALER CHARGED ME 45 DOLLARS TO REMOVE IT..THEN THE SELF CONTROL STOP WORKING.COULD NOT CUT LAWN BUT 2 TIMES BEFORE HAVING TO REPLACE THE BELT,THE DEALER SERVICE SAID IT WOULD COST ME AT A RATE OF 90 DOLLARS PLUS.NOW THE LEFT REAR WHEEL TURN SHAFT IS WORN OUT. I WILL NEVER BUY ANOTHER QNE OF THIS BRAND. ALSO HAD TO RE PLACE ALL TH CABLES AT MY COST THE FIRST MONTHS OF OWNERSHIP,IT WAS THE WAIST OF MY MONEY