How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Curtis B. Your Own Question
Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 27042
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
30244710
Type Your Small Engine Question Here...
Curtis B. is online now
A new question is answered every 9 seconds

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: 10 months ago.
Category: Small Engine
Customer: replied 10 months ago.
Just wondering how your getting on with my question ?
Customer: replied 10 months ago.
Motor is a Briggs and stratton
Expert:  Curtis B. replied 10 months ago.

Briggs and Stratton 793880 is the camshaft for this model.

Expert:  Curtis B. replied 10 months 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 10 months 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 10 months 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.