Briggs 6.5 vertical shaft

#1
Okay, I'm stumped. It's not for a mini, but I know you guys can help. I've got spark. It will run when I prime it (or on starting fluid), but it dies shortly after. I have cleaned the carb vigorously two times. There is no leak between the carb and block, and I know the main jet is clean because I've seen the carb cleaner spray through it. I have sprayed through every hole and seen the fluid go through. There is one strange hole beside the main jet, and I can't figure out if it is a jet hole. It may not even be a hole, but it looks like it could be. I've never been stumped by one of these, and it's driving me crazy!
 
#3
I'll snap a few pics this weekend. I did find a video on YouTube last night of the exact carb being rebuilt, but I've done almost everything in the video. It's back together for right now. If I pop the silver "button" off, do I need to buy a new one, or will it snap back in place? I'm gonna pop it off and really spray it well with carb cleaner, but I don't have a replacement part yet. It's the only hole I haven't totally cleared. The mower doesn't have variable speeds. It's always running on the same speed, and it will run when I prime it, but then dies after about two seconds. I also just got a set of brushes and small metal rods to clean carbs. I'll be opening this baby up again sometime this weekend!
 

125ccCrazy

Well-Known Member
#4
Is this a float style carb? if so does it have a removeable pilot jet? if both answers are yes take it out and make sure the tiny holes are clear... The silver button sounds like a welch plug..
 
#5
Mine had a crack in the intake. I know you said you don't have an air leak but mine was doing the same thing. The pull start cover rubbed the crack in it. A pick of your setup would help though.
 
#6
If you take that small silver looking cover/plug out you will need a new one. They are called welch plugs. Sounds like you do have a air leak. Pull the carb and make sure the o-ring is good along with the gasket. The other possibility is the funny looking gasket on the back side of the air cleaner that is used along with the primer bulb. If that is bad it will not stay running. Look up your motor and get a carb rebuild kit.
 

kheper

New Member
#7
Before rebuilding the carb, tighten the needle valve fully. Make a mental (or other) note as to how many 1/2 turns it takes to close it. Try to start the engine. If it catches, open the needle valve - quickly. The problem may be that the inlet valve is not seated properly, and the engine is being flooded.
 
#8
I'll stop by the local shop and pick up the new gasket that goes between the carb and air filter. I need a new Tecumseh air cleaner assembly for another project anyway. Thanks fellas. Ill post an update soon.
 
#9
David, If you have a air leak/vacuum leak It will probably be the gasket behind the carb..where it fits against the head. As far as cleaning carbs that don't run/Idle I've cleaned some carbs 3 or 4 times before I get them right. I use spray brake cleaner, compressed air and even paper clips, needles and safety pins. Good luck I hope you get it going.
 
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