Re: Toro Personal pace mower Auto Choke open at cold start
Normally on a cold start it takes 3-5 pumps but priming once the engine is warm to operating it should be necessary but I have seen a few that requires it.
Yes it can be problem with the primer for one thing or an intake air leak.
One of the problems with the primer system is that the air cleaner base which the primer is in warps over time plus many techs overtighten them try to get them to prime. Once the base is warp or damage it takes reworking the gasket to make it seal. Often times here I use two gaskets shaving one in a way that applies pressure at the point that first gasket doesn't shows making contact during test fits. Once I get a good seal contact I glue the two gaskets together and tighten the screws to about 30-35 in-lbs. Or you simply replace the air base base and gasket; again paying attention as to not overtighten.
As the possible intake air leak there an o-ring on the beside of the carburetor can leak, also intake itself can crack since it is plastic.
On top of this if the engine has a lot hours on it, it can even be a valve clearance problem. The valve on L heads (side valve) engine tends to close up clearances leading to starting problems as the compression release becomes overly active.