[AT] Briggs stumbles when load increases

[DieselBob at aol.com]

In a message dated 5/11/2005 4:04:55 P.M. Eastern Standard Time,  
robinson at svs.net writes:

On 10  May 2005 at 8:51, Len Rugen wrote:

> I have a 8 HP I/C Briggs that  is about 15 years old but has been well 
cared for.  It
> starts on  the first pull and doesn't use any oil.  Its problem is that 
when a load  hits
> it, it "stumbles" and nearly dies, then runs rough for  awhile.  If the 
load stays
> constant, it will handle it, but if it  varies, it runs bad.  It has a 
float carb, and will
> leak when not  running unless I turn off the fuel, so I know it needs at 
least a  float
> valve.  
> 
> What else could it be?   



I had a valve seat that was loose once that caused it to act up under load  
(intake if I recall - it was over 30 years ago).  I had worked on just  about 
everything trying to get it to run right.  Finally with the head off  one day I 
saw the valve seat move up.  I took a punch, and peened around  the outside 
of the seat to get it held tight. It fixed it. I don't know if it  was 
temperature that loosened it under load, but when cold it would start and  idle OK.
 
Bob 
F-12, M, 200