Question about Craftsman 46" 21hp Briggs & Stratton Turn Tight Hydrostatic Yard

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How do I set the valves,what is the setting .020?

I ran the mower a couple hours. Stopped and it won't restart. compression lock. If I remove the plug it will turn over all day. Or is there another way of timing this motor? Thanks

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No a lot closer to .005 but need the engine info to give the correct setting. .020 will definitely cause the decompression to become non-operative.

Posted on Apr 10, 2015


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Posted on Jan 02, 2017

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SOURCE: wont start

It sounds like the cylinder is filling up with gas,does it still do it after you take the plug out and crank it and put the plug back in and does it have any gas come out of the cylinder when you crank it?

Posted on Jun 03, 2010

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SOURCE: I have a 12.5hp briggs on a riding mower, hit

You can't set the timing, the flywheel is locked to the crankshaft via the key.

If you don't have compression, you may have twisted / bent the crankshaft as well, or the camshaft was damaged (though this is rare).

Why do you say that you have no compression? Did you put a compression guage onto the engine and spin it with the starter?

Does the engine happen to turn slower than before when you try to start it? A bent crank shaft can cause it to turn slower, and if it turns too slow, the compression release (if equipped) may not disengage which would cause a loss of compression.

Posted on Jun 13, 2010

Testimonial: "Thanks, the engine spins as if the spark plug was removed. When I remove the plug I canonly see the vavles, which move in and out when motor turns, In this model the piston is not visable. Trying to avoid removing head but this is my next move."

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SOURCE: My rider mower backfired and then stopped running.

loose piston wrist pin will seize an engine eventually

Posted on Apr 12, 2011

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SOURCE: Craftsman 26 hp Kohler engine 54

to be honest the enigne ahas a control that the left side must fire and run before the right starts to fire it sounds to me like you have a fuel issue possibly the carb. is gummed up and dirty.

Posted on Jul 28, 2012

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1 Answer

Why does my petrol mower not restart when hot?

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try a new spark plug and check spark when hot

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I have a 21 hp Briggs and Stratton model #331877, what are the valve settings?

Intake 003 - .005
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Adjusted with the piston 1/4" past TDC of compression stroke for each cylinder.

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I have a 14.5 hp murray riding mower i tightend the valves and now mower wont start

Steven, I think you have diagnosed your own problem. Check the specs you used to set the valve clearance. If you don't have any specs, set them both to .020" and it should run fine. Be sure that you set both valves just about 15-30 degrees before TDC on the compression cycle. (both valves closed)


Dec 16, 2012 | Murray Garden

1 Answer

I have a Craftsman mower powered by a Briggs and Stratton 775 platinum professional series with OHV. A couple of weeks after using my mower, I started it up and I heard a knocking sound I shut it off...

There is the possibility that the valves need adjusting. As you probably know, if they are too far out of adjustment, starting will be difficult and there will be "runnability" issues. The Briggs OHV engines all have adjustable overhead valves. Just remove the little cover stamped OHV, careful with the thin gasket behind it and get a feeler gauge, possibly a Torx head driver and box wrench to do the job. Some of the set screws for the rocker arms have slotted heads maybe. The Briggs site has the instructions for this and ALL the specs on all their engines pertaining to valve clearance on intake and exhaust. Many of their OHV engines also incorporate a compression release feature which correct valve adjustment is critical for it's correct operation. If you need more help or links to the Briggs help (under FAQ), then post back.
Most Briggs OHV engines are set at 1/4" past TDC on the power stroke. Many adjust them at TDC (with both valves closed), but for the sake of the compression release (works off the cam), Briggs specifies 1/4" below TDC on Power Stroke.

Jun 05, 2011 | Craftsman 675 Series 190cc 22" Briggs ...

1 Answer

Cub cadet 1405, has new battery & starter. cranks over great with plug removed , won' t crank at all with spark plug in. any ideas?

You didn't indicate which engine we are working on, but here are a couple of ideas.
It is possible that the starter is weak. If this is the problem, replace the starter.
It is also possible that the compression release is not working. Try adjusting the valves back to factory specs.
Good Luck!

Aug 27, 2010 | Cub Cadet Garden

3 Answers

Can't start brisggs & Stratton 21in mower. I

Get some GUMOUT carburator cleaner GAS ADDITIVE. Put about 1/2 TEASPOON in the gas tank and about 1 tablespoon per gallon into your spare gas. The float pin is probably sticking from winter non-use. This will free it ip.

You can also remove the bowl from the carburator and spray everything to immediately dissolve the varnish. Be careful not to lose the pin spring.

Jun 13, 2009 | Briggs & Stratton Lawn-Boy Insight Series...

1 Answer

17 hp briggs hard to start and blows back through the breather

Hello rfrazierL

>>From your Description it Sounds like the Valves Require Adjusting.
>>The Following is a Basic File I made for Setting the Valve Clearances. Any Input is Appreciated.
>>**I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best.
>>Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines).
>>Check the Push Tubes and make Sure they are Not Bent.
>>Set the Cylinder you are Setting the Valves on to Top Dead Center on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Lock and Using a Blade Style Feeler Gauge, Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .006in - .008in. Loosen and Tighten the Rocker Arm and the Feeler Gauge is Placed Between the Rocker Arm and the Valve Top where the Rocker Arm Pushes on the Valve.
>>I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Be Sure the Piston is at TDC on the Compression Stroke.**
>>If you Remove the Valve Cover and then Turn the Engine by Hand, you can Watch the Intake Valve Movement. When the Intake Valve Closes, the Piston will Just Starting the Compression/Power Stroke.
>>On Some Engines you can Us a Straightened Coat Hanger and Feel the Piston.
>>Be Careful and Don't Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems.



Apr 20, 2009 | Craftsman 42 in. Deck 19.5hp Lawn Tractor

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