Briggs and Stratton Engine- Wont start

pwgsx

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I have a Yard Machine wood chipper/ shredder with a Briggs and Stratton 4 cycle engine on it. Model 24A-462G129. Was mulching leaves with it today, it was running finefor a good 30 mins and all of a sudden it just died. I figured it was out of gas. It sounded like someone had moved the throttle to off, it throttled down and shut off....... I get the gas can and find more than a half was still in the tank. Odd.....I topped it off but it will not start back up.

Here is what I checked: It has spark, it has gas flow, clean carb ( carbwas just replaced and added new fuel line and filter- I checked anyway, its clean). Tried putting gas directly in spark plug hole- it will not fire or even sputter. Engine turns over freely and sucks air if you put your finger over the spark plug hole. Oil is full and still clean. Im stumped, I have rebuilt jet ski engines with no issues but this has got me puzzled!!!! :frown:
 

gary lee

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I check for a dirty air filter and crank the engine few times a check the end of spark plug it should be moist if dry its a carb problem.
 

reynoldston

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You have spark and fuel. Check compression and timing. You need all 4 things to run. Did you check the spark under compression?
 

pwgsx

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You have spark and fuel. Check compression and timing. You need all 4 things to run. Did you check the spark under compression?

No not yet.......what should the compression be for a small engine like that?
 

pwgsx

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I would say 100+.

Ok, did compression check, pulled the cord 5 times and its about 20psi. I added a few drops of oil in the plug hole and still got the same number. Does this mean a blown engine?? I have only worked on 2 strokes and everytime the engine blows, the pistons wont move. This however is turning freely. Could it be bad valves that are stuck open? When I pull the cord, air comes pumping out of the OHV cover thru the hose that runs to the air filte box. Is that normal? I have never worked on a 4 stoke so im in the dark on when to look for.

thanks for help!
 

Carscw

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Briggs says, remove the cooling shroud, remove the plug wire. Rotate the engine backwards by hand until you feel resistance, then with one move, spin it forwards, then back against the compression. If the engine bounces sharply forward...there is adequate compression to start and run. If it doesnt sharply bounce...there is a problem.

4 bars is about 60psi, which is a good number to be around, 80-90 is very difficult to recoil start.

Sent from my iPhone using LMF
 

reynoldston

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The first thing to check would be the valve adjustment. .006 intake .012 exhaust. Do what carscw told you to do because some engines have a decompress-or to start.
 
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