Need help with Briggs&Stratton twin

[KBennett]

I just got a free Monkey Ward riding mower with an 18HP Briggs twin.

I got it home, fired it up, and the motor is making a clacking sound but runs very smooth with no smoke. The sound is almost like a rod knock but more metallic like it's in the valve train. It is a flathead design so I don't think the valves can be adjusted??? Is there something common in these motors that makes the sound or should I tear into it?

 

[SRadke]

Is it a V twin engine or an inline? I guess it's called an inline with only two cylinders?



-Scott

 

[KBennett]

It's horizontally opposed, not a V-twin

 

[B.G. Smith]

Clack

Pull the little covers off and check the valve clearance. Some have adjustable valves. If you can hear it above the engine noise, I doubt it is a valve, more than likely a rod. You might be able to determine if a rod is loose by removing the spark plugs and turning the engine by hand until the piston is on the down stroke, then insert a wood dowel through the plug hole and push on the piston, might be able to feel the slack. bg