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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 27787
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a 21b807 that is very hard to start when cold, piston

Customer Question

Hi there, I have a 21b807 that is very hard to start when cold, piston reaches tdc and struggles to go further, is there a higher torque starter available( battery is new and always trickle topped up)
Submitted: 1 year ago.
Category: Small Engine
Customer: replied 1 year ago.
Just wondering how your getting on with my question ?
Customer: replied 1 year ago.
Motor is a Briggs and stratton
Expert:  Curtis B. replied 1 year ago.

Briggs and Stratton 793880 is the camshaft for this model.

Expert:  Curtis B. replied 1 year ago.

What you have is too much compression. First thing t check is the valve clearance, needs to be set on the low side,.004 to .006 inch, intake and exhaust. If it does not help, run a compression test and if the compression is 100 psi or more, your camshaft with the compression release on the back side of the camshaft gear is broken.

Expert:  Curtis B. replied 1 year ago.

The compression release is a spring loaded weight , on the back side of the gear and if it breaks, do not release the compression for easy start. Repair is to replace the camshaft! Common failure on this camshaft!

Expert:  Curtis B. replied 1 year ago.

There is no high torque starter for the engine. You may want to check voltage to the starter when it is engaged, and if the voltage stays above 8 volts, battery and starter are ok.