Got everything put back together fully with a new crankcase cover gasket and went out to test it again to see if messing with the govenor did anything. Still does it (choke flapping) but once it warms up enough it to the point where the thermostat on the exhast fully opens and pushes the arm/linkage it runs beautifully..
Briggs and Stratton Auto Choke on Toro Problem
- Thread starter Stihleer
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bertsmobile1
Lawn Royalty
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You might need to bend the connecting wire from the auto choke to the choke in order to put more pressure on the choke to open & not flap.
Wondering how this turned out as I'm having the identical problem and I have a hypothesis if you'll indulge me.
I'm having this same issue with a Briggs power washer. I'm starting to think it's a faulty auto choke. I'm trying to find out how long it should take for the auto choke thermostat to fully actuate but can't seem to find the information. I've timed the one I have and it's anywhere from 3 to 4 minutes, which seems excessive.
It appears as if the choke spring holds the choke closed, not open. So a tighter spring may not solve the problem. The O.P. said that this happens when the blade is engaged. I have the same symptoms when I engage the water pump.
There's no throttle on this so it runs full. When not under load, the governor is putting closing pressure on the throttle, which in turn, puts pressure to open the choke (the way it's designed with the oblong interference linkage). When it comes under load, the governor releases the pressure and the governor spring opens the throttle, which takes the pressure off the choke lever allowing the choke spring to close the choke unless the thermostat is putting pressure back on the choke arm.
This appears to start the oscillation as the airflow is interrupted and the governor tries to stabilize things. Because of the way it's designed, this starts a sort of oscillation causing the choke to flap, until the mechanism of the thermostat kicks in and puts permanent pressure, holding the choke open. If I take a screwdriver, hold the choke open, and then engage the water pump, everything runs perfectly. This appears to be why after it warms up (almost 5 minutes), everything is fine. But I think the problem is that the thermostat choke is faulty in some way and taking too long to fully heat up and engage. Does this make sense?
I'm having this same issue with a Briggs power washer. I'm starting to think it's a faulty auto choke. I'm trying to find out how long it should take for the auto choke thermostat to fully actuate but can't seem to find the information. I've timed the one I have and it's anywhere from 3 to 4 minutes, which seems excessive.
It appears as if the choke spring holds the choke closed, not open. So a tighter spring may not solve the problem. The O.P. said that this happens when the blade is engaged. I have the same symptoms when I engage the water pump.
There's no throttle on this so it runs full. When not under load, the governor is putting closing pressure on the throttle, which in turn, puts pressure to open the choke (the way it's designed with the oblong interference linkage). When it comes under load, the governor releases the pressure and the governor spring opens the throttle, which takes the pressure off the choke lever allowing the choke spring to close the choke unless the thermostat is putting pressure back on the choke arm.
This appears to start the oscillation as the airflow is interrupted and the governor tries to stabilize things. Because of the way it's designed, this starts a sort of oscillation causing the choke to flap, until the mechanism of the thermostat kicks in and puts permanent pressure, holding the choke open. If I take a screwdriver, hold the choke open, and then engage the water pump, everything runs perfectly. This appears to be why after it warms up (almost 5 minutes), everything is fine. But I think the problem is that the thermostat choke is faulty in some way and taking too long to fully heat up and engage. Does this make sense?
Certainly. Top down, front and then the front with the throttle held closed (Order of photos).
The default position when off is throttle wide open, choke closed. All handled by the springs you see. Once the engine starts and goes up to RPM, the governor closes the throttle a bit because there's no load. The closing of the throttle pushes the choke open quite a bit. So it runs fine at full throttle during this time. Once under load, the governor pushes the throttle open which appears to allow the choke to close. I apologize for being redundant. It's just so confusing to me so I keep saying it over and over again to make sure I'm saying what I'm thinking. Once up to temp, the thermostat pushes against the choke's spring tension and holds it open. But that takes a substantial amount of time, several minutes.
The default position when off is throttle wide open, choke closed. All handled by the springs you see. Once the engine starts and goes up to RPM, the governor closes the throttle a bit because there's no load. The closing of the throttle pushes the choke open quite a bit. So it runs fine at full throttle during this time. Once under load, the governor pushes the throttle open which appears to allow the choke to close. I apologize for being redundant. It's just so confusing to me so I keep saying it over and over again to make sure I'm saying what I'm thinking. Once up to temp, the thermostat pushes against the choke's spring tension and holds it open. But that takes a substantial amount of time, several minutes.
You just answered your question. It needs a new thermostat. You said once it warms up it runs perfect. Something in that thermostat is not working properly. Stop messing with springs and governors.
slomo
If the governor is not adjusted properly, it is going to bounce. Have you checked the governor top speed, if the governor is not adjusted to the recommended top speed (spring controls this) the governor will pushed the throttle open. More than once I’ve seen where customers have played with the governor to get more speed, screwing up the carb.