Export thread

Briggs

120602
0164-E1
020507 FA

New carb Briggs part number 790120. Changed oil, new mower blade, new air filter, new spark plug(Torch), and new engine stop cable. Checked flywheel key and its was good.

Engine rpm's on top speed arent all there unless its Briggs low noise engine. Same type of thats on JD walk behind and everything is same between the 2 engines. Seems hard to start when warm/hot. Started right up when cold start.

Any ideas? Are the valves adjustable on this engine?

the only way to know for sure if you have low rpm's is your going to need a tach.

ILENGINE said:

the only way to know for sure if you have low rpm's is your going to need a tach.

Click to expand...

OK, But I can tell by the sound that its not very loud and self propelled is slow also.

Check throttle cable if you have one. Make sure it opens the butterfly all the way.

Check auto choke make sure it has full range of movement.
While running play with the butterflys on the carb see if they are open.

Next check govenor ARM see if it needs adjusting. When hot it should open the carb up all the way.

Couple of things to try for hard hot start.

The intek has to have spark plug set at 0.020".
The black spacer between the carb and head can distort when engine warmed up allowing more air in than fuel.
Has the safety cut off switch sufficient clearance between the lever when cable operated?
its an ohv engine so rocker cover off.
I think clearances are 0.04"-0.06".

pugaltitude said:

Couple of things to try for hard hot start.

The intek has to have spark plug set at 0.020".
The black spacer between the carb and head can distort when engine warmed up allowing more air in than fuel.
Has the safety cut off switch sufficient clearance between the lever when cable operated?
its an ohv engine so rocker cover off.
I think clearances are 0.04"-0.06".

Click to expand...

I cleaned the black spacer when the carb was replaced with new gaskets. I manually move the governor to rev the engine rpms up but when the engine rpm's came down I kept hearing a pop sound.

Popping screams valve adjustment to me

pugaltitude said:

Couple of things to try for hard hot start.

The intek has to have spark plug set at 0.020".
The black spacer between the carb and head can distort when engine warmed up allowing more air in than fuel.
Has the safety cut off switch sufficient clearance between the lever when cable operated?
its an ohv engine so rocker cover off.
I think clearances are 0.04"-0.06".

Click to expand...

Intake is .003-.005 and exhaust .005-.007 for valve clearance. Air gap .010-.014. Per Briggs manual.

davbell22602 said:

Intake is .003-.005 and exhaust .005-.007 for valve clearance. Air gap .010-.014. Per Briggs manual.

Click to expand...

Is that not horizontal shaft specs?

pugaltitude said:

Is that not horizontal shaft specs?

Click to expand...

Its specs for the 120000 series OHV single cylinder vertical shaft.

Thats for L head engine.
OHV model 12 is 0.004"-0.006" for vertical both valves.
0.004"-0.006" inlet and 0.009"-0.011" ex horizontal.

pugaltitude said:

Thats for L head engine.
OHV model 12 is 0.004"-0.006" for vertical both valves.
0.004"-0.006" inlet and 0.009"-0.011" ex horizontal.

Click to expand...

Then there's a typo in the manual because that what is says in single cylinder OHV manual part number 276281.