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Craftsman briggs and stratton Platinum 21 HP 540cc XRD

#1

M

mpucci67

Engine started running rough. Would die at low idle speed...a few days later if appear to have a week battery and had to charge it to start the motor...it was time to do a spring time up anyway so changed oil & filter, air filter, spark plug....Sent to restart and it would not Frank completely over again..changed out battery and still would not crank fully...plug plug and was able to crank the motor freely, checked spark, it was decent. Took cool off, cleaned minor rust off of the face and check resistance on both legs to the plug wire 6k ohms also key switch wire was 6k...put the plug back in and now the motor still will not crank over completely


#2

Scrubcadet10

Scrubcadet10

Sounds like valves need adjusted.
give us the engine Model number also, please. Should be stamped into the OHV valve cover


#3

M

mpucci67

Sorry, I didn't see your reply until today. Here is the model #331877 type #1371 B1


#4

Scrubcadet10

Scrubcadet10

Okay, could be 2 or three things, the first is least likely which is a weak starter, 2nd would be valves out of adjustment, 3rd, is this engine has the briggs and stratton 793880 camshaft, prone to wiping the Compression release out in it and causing hard starting.
i would remove the valve cover spark plug, and turn the engine over by hand, and watch the valves moving, after the intake valve closes, (someone may have to correct me on this) the exhaust valve should just bump open a little bit, not fully open, just a bump to relieve the strain on the electric starter. I can't remember on this engine if the compression is relieved through the intake or exhaust.
the old part number was upgraded and superceded to 84005207 and i believe it doesn't come with new solid lifters, so you'll have to order those seperate, IF it's the cam.


#5

I

ILENGINE

Scrub the Intek single uses a crossflow head so the intake is on the bottom which is where the ACR is located.


#6

S

slomo

mpucci67 said:
Engine started running rough. Would die at low idle speed...a few days later if appear to have a week battery and had to charge it to start the motor...it was time to do a spring time up anyway so changed oil & filter, air filter, spark plug....Sent to restart and it would not Frank completely over again..changed out battery and still would not crank fully...plug plug and was able to crank the motor freely, checked spark, it was decent. Took cool off, cleaned minor rust off of the face and check resistance on both legs to the plug wire 6k ohms also key switch wire was 6k...put the plug back in and now the motor still will not crank over completely
Click to expand...
Dirty carb
Weak battery
Like others said, valve clearance check
Clean engine block cooling fins all around the cylinder/s yearly or more often if you bag or sling grass.
Check and clean all ground points
Rust on a coil has zero issues firing a plug. Same with a rusty flywheel.
Remove plug and try to crank over. If it cranks easy, look at the compression release slash cam issue like the others said.

slomo


#7

M

mpucci67

Scrubcadet10 said:
Okay, could be 2 or three things, the first is least likely which is a weak starter, 2nd would be valves out of adjustment, 3rd, is this engine has the briggs and stratton 793880 camshaft, prone to wiping the Compression release out in it and causing hard starting.
i would remove the valve cover spark plug, and turn the engine over by hand, and watch the valves moving, after the intake valve closes, (someone may have to correct me on this) the exhaust valve should just bump open a little bit, not fully open, just a bump to relieve the strain on the electric starter. I can't remember on this engine if the compression is relieved through the intake or exhaust.
the old part number was upgraded and superceded to 84005207 and i believe it doesn't come with new solid lifters, so you'll have to order those seperate, IF it's the cam.
Click to expand...

What should the valve lash clearance be set to? I would like to try set the valves before pulling the cam


#8

Scrubcadet10

Scrubcadet10

Intake Valve Clearance .003 - .005 in (0.08 - 0.13 mm)
Exhaust Valve Clearance.005 - .007 in (0.13 - 0.18 mm)


#9

M

mpucci67

Scrubcadet10 said:
Intake Valve Clearance .003 - .005 in (0.08 - 0.13 mm)
Exhaust Valve Clearance.005 - .007 in (0.13 - 0.18 mm)
Click to expand...


excellent....thank you for all the help. It work fantastically. I knew this worked as soon as I put the spark plug back in. I was able to spin the engine over a complete rotation by hand. Once I hit the key the not tired up instantly


#10

4

4950cycle

mpucci67 said:
excellent....thank you for all the help. It work fantastically. I knew this worked as soon as I put the spark plug back in. I was able to spin the engine over a complete rotation by hand. Once I hit the key the not tired up instantly
Click to expand...
Not tired up instantly ? What


#11

4

4950cycle

mpucci67 said:
excellent....thank you for all the help. It work fantastically. I knew this worked as soon as I put the spark plug back in. I was able to spin the engine over a complete rotation by hand. Once I hit the key the not tired up instantly
Click to expand...


#12

4

4950cycle

The not tired up ? ?


#13

David_54b

David_54b

I have a craftsman riding mower, Model: 331877, Type: 2371 G5. I can get the mower to start but when it does it smokes like crazy. It has sat for almost two years in a shed. I have already changed the oil, plugs, fresh gas, and brand new battery. I'm thinking it could be a valve seal if their are any in these motors.


#14

S

slomo

David_54b said:
I have a craftsman riding mower, Model: 331877, Type: 2371 G5. I can get the mower to start but when it does it smokes like crazy. It has sat for almost two years in a shed. I have already changed the oil, plugs, fresh gas, and brand new battery. I'm thinking it could be a valve seal if their are any in these motors.
Click to expand...
Thanks for letting us know.


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