Walk behind 1999 SilverPro model 10323 has whooping cough.

[blowerhead]

Earlier this summer, the carb leaked gas into the cylinder, engine would not turn over when starter rope pulled. Removed spark plug, pulled starter rope, and blew gas out thru spark plug hole. After that, the engine makes a whooping noise when starter rope is pulled, noise I never noticed before.
Disassembled and cleaned carb jets, still leaked, finally installed a new carb, started on first pull. That's when the noise was first noticed when pulling starter rope, even tho it ran fine afterwards. Since then, the spark plug threads stripped out, and am replacing the head. With head removed and engine hand rotated, the whooping noise is very noticeable. Is this normal or is the engine sick?

 

[jp1961]

Hello,

The whooping noise is just the suction action of the piston going towards TDC, bringing the next air/fuel charge into the crankcase for the next explosion.

Regards

Jeff

 

[blowerhead]

Hello,

The whooping noise is just the suction action of the piston going towards TDC, bringing the next air/fuel charge into the crankcase for the next explosion.

Regards

Jeff

Thanks again, Jeff

 

[Russ2251]

Emanates from reed valves.

 

[blowerhead]

Emanates from reed valves.

I see those reed valves in the intake, whats their purpose?

 

[Russ2251]

Reed valves allow fuel/air mixture to enter crankcase on the intake cycle.
That is, the valves open when there is a negative pressure, or vacuum in the crankcase.
https://en.wikipedia.org/wiki/Two-stroke_engine#Reed_inlet_valve

 

[blowerhead]

Reed valves allow fuel/air mixture to enter crankcase on the intake cycle.
That is, the valves open when there is a negative pressure, or vacuum in the crankcase.
https://en.wikipedia.org/wiki/Two-stroke_engine#Reed_inlet_valve

Great reference, thanks