Contents
- 1 How do you check the valve clearance on a Briggs and Stratton engine?
- 2 Which is the intake valve on a Briggs and Stratton?
- 3 What is the valve clearance on a 21 HP Briggs and Stratton?
- 4 What happens if Valve clearance is incorrect?
- 5 How do you adjust valve clearance?
- 6 How do I know which valve is intake and exhaust?
- 7 Why is my riding mower hard starting?
How do you check the valve clearance on a Briggs and Stratton engine?
How to Adjust Overhead Valves
- Step 1: Release the brake spring.
- Step 2: Insert a narrow screwdriver into the spark plug hole and touch the piston.
- Step 3: Check the valve clearance by placing a feeler gauge between the valve head and the rocker arm.
- Step 4: Adjust the clearances as required by turning the rocker screw.
Which is the intake valve on a Briggs and Stratton?
Briggs & Stratton Intake and Exhaust Valve Clearances
| Model Series | Engine Type | Intake Valve Clearance ( in. ) |
|---|---|---|
| 310000 | OHV Single Cylinder | .003 /.005 |
| 290000, 294000, 303000 | OHV Twin Cylinder | .004 /.006 |
| 350000 | OHV Twin Cylinder | .004 /.006 |
| 380000 | OHV Twin Cylinder | .004 /.006 |
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What is the valve clearance on a 21 HP Briggs and Stratton?
If it turns out that the engine is a 33M677/0149-B1, the required valve clearances are 0.003-0.005″ for both intake and exhaust, but this is different for each different engine size, so let’s make sure we are talking about the right engine.
What happens if Valve clearance is incorrect?
Too much clearance means the valves will likely clatter and, over the long term, cause damage to the valves, camshaft lobes or rocker arms. If there’s too little valve clearance, the valves won’t fully close, causing excessive heat, and the engine will lose power.
How do you adjust valve clearance?
Use a ring spanner to loosen the locknut and turn the screw clockwise to decrease the gap, and the opposite way to increase it. When the clearance is correct, hold the screw with a screwdriver while you tighten the locknut, then re-check the clearance.
How do I know which valve is intake and exhaust?
The intake valve /rocker will line up with the intake port. The exhaust valve /rocker will line up with the exhaust port.
Why is my riding mower hard starting?
A clogged fuel filter is most commonly caused by leaving old fuel in the lawn mower. This sticky fuel can clog up the fuel filter and make the engine hard to start. If old fuel was left in the lawn mower, drain the old fuel from the fuel tank and replace the fuel filter.