Fixing Briggs and Stratton 6 HP Quantum lawnmower engine

[nbpt100]

The Briggs 90000/10000 series(Classic, Sprint, Quartro) are robust too. I like them. Also, no longer made. Not as powerful as the Quantum. They are more in the 3 to 4.5 HP range. The 3/4" shafts are more prone to bending in a collision with a rock or stump, on mowers with longer blade adapters. Good push mower engines. I have never had any reason to put thicker than 10w-40 in a small engine. I guess 20w-50 oil would quiet it down some. Actually, I did once try 20w-50 in a Quantum that smoked a little. I reverted back to straight 30 as it smoked less overall. At start up the 20w-50 it smoked terribly. I realized the cold oil at 20w would leak more through the rings than the straight 30. I would have put in straight 40 if I had it. It is not easy to find SAE 40 any more.

 

[super20dan]

so glad my last pos quantum gave up. never going back mostly run kawasaki in my commercial mower 21 in fleet. done with lawnboy also with their junk ignition coils! believe it or not still have several Tecumseh still on the job

 

[97prizm]

I recently solved the no-start issue on a 6 HP B&S mower engine. It’s 20 years old and was the series when they used a red bulb to prime the engine rather than have a real choke assembly. This engine is overly susceptible to a no-start condition due to old gas and the carb can get clogged up easily.

The red bulb actually pumps air to cause a venturi effect to bring gas from the bowl into the carb and uses a large plastic plate assembly to house the bulb and priming circuit.

You tube videos suggest doubling up the gaskets between the carb and plate, and removing the bulb assembly and cleaning it up. Those things did not work here. I also removed the bowl and sprayed the carb with carb cleaner with no improvement.

The easy way out was to order a carb kit made in China that came with a new carb, plate, fuel hose, shut-off valve, gas filter, air filter, governor springs, spark plug, blow by hose, clamps, heavy duty air filter cover all for $30 US. It runs fine now, and has the shut off valve and fly screen filter installed. Incidentally, this is for the widow of the LEO who has a place down the street. Here are a few shots. Enjoy.

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I've never seen a brute brand mower. Was it one of the Murray, or yard machines clones?

 

[super20dan]

put together a snapper commercial 21 today using the last of my spare parts from Wisconsin robin 2 stroke engines

 

[super20dan]

project done! runs great going to work tomorrow. these robin 2 cycles are the best ever made. parts supply has all but dried up now .