Picked up a $20 Toro 20334 with b&s 190cc 128T02-3125-B1. Would not start. Cleaned carb in ultrasonic cleaner, cleaned gas tank, new air filter and changed plug. Started on 2nd pull sounded good. Mowed my yard, when I stopped to empty the bag it would not start again. Removed gas cap in case it was not venting, no start. Changed spark plug, no start. Changed coil with a known good one, no start. Let it sit for 12-15 minutes and it started but was running really slow rpm, but the throttle was wide open. Let it sit for another 10 minutes and it started again but still slow rpm. After about 30 seconds it jumped to full speed and seemed to run fine. Finished the yard and after shutting it off, had the same no start and after setting a while had the same slow rpm then jumping to full speed. Anyone experienced this before?
Stumped, slow start, jumps to full throttle
- Thread starter slow030
- Start date
Does it say Torch on it?
Check the autochoke.
Pull the top engine cover off. Take a picture of the carb linkage and the autochoke parts. There is a thermostat that is behind the muffler. Good shots of that too. All around the head and flywheel pics please.
Auto Doc's
Lawn Addict
Hello S.,
Pull the top engine cover off and look at the choke lever portion on top of the carburetor. B&S had issues with the choke plastic portion on top of the carburetor dragging the stamped air cleaner mount. Removing the carburetor changes the close tolerances needed for this lever to move freely.
A light sanding on the plastic edge to give it more clearance works well to resolve the issue.
Pull the top engine cover off and look at the choke lever portion on top of the carburetor. B&S had issues with the choke plastic portion on top of the carburetor dragging the stamped air cleaner mount. Removing the carburetor changes the close tolerances needed for this lever to move freely.
A light sanding on the plastic edge to give it more clearance works well to resolve the issue.
I'm lost on this. I've haven't seen this.
There is an air vane that can drag in its single 1/4" hex head screw mount. Thermostat pushes the air vane towards the spark plug and opens the choke.
On these Briggs autochokers, best to set engine rpm to 3600 and leave the speed alone. Use the dead man lever to kill the engine as normal. Make a single speed engine out of it. Some like on a Snapper have adjustable throttle cables that are really not needed.
Need to confirm the thermostat is working proper. You can remove the muffler and the thermostat. Take a propane torch to the thermostat and watch the lever move when heated. Duplicates muffler heat in real world ops. Heat around where the exhaust port is on the thermostat. Not on the round heat sensitive spring canister deal. Should remain in the extended position for a minute or two after the heat is gone. Then go back to a resting cold position.
Need to confirm the thermostat is working proper. You can remove the muffler and the thermostat. Take a propane torch to the thermostat and watch the lever move when heated. Duplicates muffler heat in real world ops. Heat around where the exhaust port is on the thermostat. Not on the round heat sensitive spring canister deal. Should remain in the extended position for a minute or two after the heat is gone. Then go back to a resting cold position.
Waiting on the pics.
Auto Doc's
Lawn Addict
Hi Slomo,I'm lost on this. I've haven't seen this.
There is an air vane that can drag in its single 1/4" hex head screw mount. Thermostat pushes the air vane towards the spark plug and opens the choke.
What you are referring to is an air vane governor which controls the throttle when the engine is under load.
The choke is closest to the carburetor opening at the air box. The choke top lever on the carburetor has a linkage rod that runs over to the muffler that has a thermal sensor disc (thermostat)
