Toro model 20331 6.75 Briggs no choke/no prime cold start issue

R

RayMcD

Well-Known Member
Ladies & Gentlemen, I seek your wisdom. My mower will start fine but when cold it takes several minutes of sputtering and puffing black smoke to decide to speed up and run. It has new carb, coil and plug. Once it warms up and starts first pull every time and runs fine.
 
The 20331 is a generic number. There is a 20331 and a 20331 C. There are three versions of a 20331 C. There are five versions of a 20331. If I go to the Toro site and put in 20331 to see what you have, I will first have to guess at your serial number, and next guess at which engine you have, because most likely Toro will put a blurb on the page that tells me to look up engine parts at the engine manufacturer's web page. So besides this website only working for me 10% of the time, I'll have to spend hours trying to understand what you have before making a suggestion what might be the cause. Maybe someone else will know better than I what you actually have. Your problems are likely to be in the choke system, which ever kind you have. A Toro model number and serial number would help, as will the manufacturer model and serial number of the engine.
 
sgkent said:
The 20331 is a generic number. There is a 20331 and a 20331 C. There are three versions of a 20331 C. There are five versions of a 20331. If I go to the Toro site and put in 20331 to see what you have, I will first have to guess at your serial number, and next guess at which engine you have, because most likely Toro will put a blurb on the page that tells me to look up engine parts at the engine manufacturer's web page. So besides this website only working for me 10% of the time, I'll have to spend hours trying to understand what you have before making a suggestion what might be the cause. Maybe someone else will know better than I what you actually have. Your problems are likely to be in the choke system, which ever kind you have. A Toro model number and serial number would help, as will the manufacturer model and serial number of the engine.
Click to expand...
Yep, probably a choke issue.
 
sgkent said:
The 20331 is a generic number. There is a 20331 and a 20331 C. There are three versions of a 20331 C. There are five versions of a 20331. If I go to the Toro site and put in 20331 to see what you have, I will first have to guess at your serial number, and next guess at which engine you have, because most likely Toro will put a blurb on the page that tells me to look up engine parts at the engine manufacturer's web page. So besides this website only working for me 10% of the time, I'll have to spend hours trying to understand what you have before making a suggestion what might be the cause. Maybe someone else will know better than I what you actually have. Your problems are likely to be in the choke system, which ever kind you have. A Toro model number and serial number would help, as will the manufacturer model and serial number of the engine.
Click to expand...
model 20331 SN 290134829
 
according to the Toro website, it is a Briggs and Stratton engine 124T02-0203-B1 with an auto choke. Is so, my GUESS would be a something in that area. But who knows, it also shows a primer bulb type base so sometimes those warp. Or maybe the valves are tight and need adjustment. Easiest test for valves would be to see what the compression is. If it is low then it could be valves. If it is normal, then maybe not. Consider this youtube explaining the autochoke. Kind of goofy guys but they go into detail.

You can pull the air cleaner and probably see if the choke is closing properly. If not it can also be stuck from carbon deposits or dried fuel (varnish).

 
Last edited:
Remove the air cleaner and housing from the engine. Please remove the spring connecting the engine to the plastic choke shaft and store it safely. DO NOT lose it; put it somewhere safe. Remove the 1/4" bolt holding the auto choke shaft to the carburetor and remove it from the engine. After removing the plastic component with the shaft from the carburetor and engine, blast carb cleaner through the bolt hole. Lube the nub where it attaches to the choke arm by spraying some white lithium grease on it and into the bolt hole. Make sure that the choke arm moves freely, and if not, clean the top and bottom of the shaft bushings with carb cleaner. Reassemble the auto choke shaft and gently tighten the 1/4" bolt, making sure to correctly insert the nub that engages the choke rocker. Now carefully attach the spring you removed in the beginning steps; DO NOT lose it. Please ensure that the auto choke shaft moves freely throughout its entire range of motion. Prior to installing the air cleaner, do a test run on the machine and observe its performance. If all is well, install the air filter housing and filter, and retest. This should resolve the issue.
 
Last edited:
I have worked on two Briggs with stuck auto-chokes. Still in the anecdotal category of evidence, but for what it’s worth, both of the ones I fixed had the lever on the autochoke stick so the choke was always open. I did all the lubing that Kevin recommended but have to admit that all was well after I manually moved the lever on the autochoke back and forth a few times until the spring closed the choke on its own.
 
Gentlemen, you tips proved most helpful. I discovered two problems. The coil I replace earlier had a slightly larger profile and cause the vain to drag across it. I corrected this by simply sanding down the corner. Also, someone actually assemble the machine incorrect by attaching the thermostat arm to the vain, this has been corrected. Machine now cranks easily and runs like a new one.
Your assistance was most appreciated, Ray
 

Attachments

  • vain.jpeg
    vain.jpeg
    837.1 KB · Views: 22
  • thermostat arm.jpeg
    thermostat arm.jpeg
    63.6 KB · Views: 20
kbowley said:
Remove the air cleaner and housing from the engine. Please remove the spring connecting the engine to the plastic choke shaft and store it safely. DO NOT lose it; put it somewhere safe. Remove the 1/4" bolt holding the auto choke shaft to the carburetor and remove it from the engine. After removing the plastic component with the shaft from the carburetor and engine, blast carb cleaner through the bolt hole. Lube the nub where it attaches to the choke arm by spraying some white lithium grease on it and into the bolt hole. Make sure that the choke arm moves freely, and if not, clean the top and bottom of the shaft bushings with carb cleaner. Reassemble the auto choke shaft and gently tighten the 1/4" bolt, making sure to correctly insert the nub that engages the choke rocker. Now carefully attach the spring you removed in the beginning steps; DO NOT lose it. Please ensure that the auto choke shaft moves freely throughout its entire range of motion. Prior to installing the air cleaner, do a test run on the machine and observe its performance. If all is well, install the air filter housing and filter, and retest. This should resolve the issue.
Click to expand...
Sir, your post made me go look again and ultimately cause me to discover the problem, thank you, ray
 
You must log in or register to reply here.
Back
Top