Won't stay started
#1
Won't stay started
I prime this B&S engine and it starts, but within a few seconds it stops, apparently after it uses up the fuel from the prime
What should I check first?
Can't find a placard on the engine with an actual serial number but the owner's manual says
Model 120000 Quantum 600 series, 625 series, 650 series, 675 series.
Photo below.
What should I check first?
Can't find a placard on the engine with an actual serial number but the owner's manual says
Model 120000 Quantum 600 series, 625 series, 650 series, 675 series.
Photo below.

#2
Take the bolt out that holds the bowl on the carburetor and clean it well. There are tiny holes in that bolt that are probably plugged.
#3
The model, type an code are usually stamped in the metal shroud just above the spark plug or on the matal tab over the muffler. The bolt that holds the carb bowl on is the main jet and is probably clogged, clamp off the fuel line and remove the bolt, it has a hole down through the center and one across the bottom, check the pic below for reference. Have a good one. Geo

#6
Thanks for the good advice - didn't work tho. Guess I'll be looking for a carb rebuild kit now. Should this cover me?
Amazon.com : Briggs & Stratton 498260 Carburetor Overhaul Kit : Lawn Mower Parts : Patio, Lawn & Garden
Amazon.com : Briggs & Stratton 498260 Carburetor Overhaul Kit : Lawn Mower Parts : Patio, Lawn & Garden
#8
OK, so cleaned everything with carb cleaner, cleaned holes with wire, replaced gaskets, reassembled. Now it won't start, period without started fluid. Did I reassemble something wrong maybe? I'm not sure I'm feeling suction as I pump the priming bulb.
For the life of me I can't figure what the pathway is the bulb is sucking through. It seems to connect to a passage molded inside the plastic air cleaner cover.
For the life of me I can't figure what the pathway is the bulb is sucking through. It seems to connect to a passage molded inside the plastic air cleaner cover.
#9
The primer isn't sucking anything, it pumps a little air into the carb. You won't feel it doing anything. Look in the throat of the carb and see if you see a little gas bubble up from the tube in the center when you hit the primer. If not, the bowl gasket is out of place, or the gasket between the carb and filter housing is bad, or something is still clogged.
#10
I could swear in the past I've felt distinct resistance from the bulb as if it were pumping something, in fact I'm checking my trimmer, blower, chain saw, pressure washer, etc. and they all are sucking fuel into eithter the bulb or the carb bowl. My impression on this engine was that it was either sucking or pushing fuel into the bowl because of the resistance you feel in the bulb after the 2nd and 3rd pumps. Not?
Anyway, should I be trying to clean the pathway the bulb is pulling air or fuel through, whether "suction" is the word for it or not?
Anyway, should I be trying to clean the pathway the bulb is pulling air or fuel through, whether "suction" is the word for it or not?
#11
Your trimmer, blower, etc.. works the way you described, but this does not. It just pumps a little air into the carb bowl, which forces fuel out the little pipe in the middle of the carb. Is this happening?
#13
Bend that flat piece of metal away enough so that you can see in the throat of the carb and hit the primer a few times while you're watching in the throat and see if it's bubbling some gas in there or not.
#14
If you damaged the gasket between the carb and air filter cover it will not prime as the gasket is part of the primer circuit, if damaged the gasket must be replaced. Have a good one. Geo
#15
No gas visibly bubbling in carb throat. I thought that was obvious with no resistance on the bulb. No smell of gas either. Gasket between carb and air filter cover seems fine.
#16
The bulb ends in a hole in a slot in the plastic ac cover. The slot travels 1/4 circle around outer edge of carb and looks like it should align with a small hole with a slant in carb wall just below one of the screw holes for the ac cover bolts - i.e. it looks like the bulb should suck or push air thru this hole. True?
If so there is no hole in the ac gasket, i.e. the gasket covers the hole. Does that sound wrong? Maybe the dealer gave me the wrong gasket??
If so there is no hole in the ac gasket, i.e. the gasket covers the hole. Does that sound wrong? Maybe the dealer gave me the wrong gasket??
#19
Post the engine model, type and code usually stamped in the metal shroud just above the spark plug or on the metal tab above the muffler so we know what engine you actually have, the numbers posted at the beginning of the thread are general which covers many engines. Have a good one. Geo
#20
Thanks! Engine: 126102-0139-B1 07062058. I've tried searching every which way but was having no luck.
The gasket installed now is part #696024. Bolt holes and carb opening align perfectly although it seems to have a larger outside diameter than the carb, and has a couple of holes that don't line up with anything.
The gasket installed now is part #696024. Bolt holes and carb opening align perfectly although it seems to have a larger outside diameter than the carb, and has a couple of holes that don't line up with anything.
#21
There should be a hole lining up with the hole in the end of the slot in the air filter box. If not, you have the wrong gasket or it's installed wrong. Even when it's right, you won't feel the resistance of anything but air in the primer (it'll feel the same as it does now).
#22
Thanks, that's what I thought about the gasket. Re the resistance controversy - I've had it for years and I know I felt resistance! But many thanks for the help.
Followup question, if I squirt some starter spray in the carb with the ac off, should it start and stay started?
Followup question, if I squirt some starter spray in the carb with the ac off, should it start and stay started?
#24
Could not find 126102-0139-B1 in the B&S system, could the model be 126T02 if so the gasket part number would be 795629, also make sure the "O" ring gasket behind the carb is not damaged if so it will create a massive air leak. Have a good one. Geo
#25
Could not find 126102-0139-B1 in the B&S system, could the model be 126T02 if so the gasket part number would be 795629
#26
Followup question, if I squirt some starter spray in the carb with the ac off, should it start and stay started?
Yep, it should.
Hey this is pretty nice! Three weeks with an excuse not to mow!
#29
Back on this now. Cleaned carb again. Yes it's sparking. Finally got it going with starter fluid. Ran fine for mowing for over an hour. But not priming and once I turn it off and it sits awhile it won't start without starter fluid. Not seeing gas bubbling into carb.
#30
While it is running spray/dribble some carb/brake cleaner behind the carb to see if the engine tempo changes if it does the gasket behind the carb is failing and creating an air leak, if it has an air leak it would be sucking air from there rather than through the carb. Have a good one. Geo
#31
If it won't prime, the gasket between the air filter housing and the carb is not sealing, and/or the bowl gasket is not sealing. You primer does have a hole in it, right?
#33
The bowl may be distorted so that it's not pressing against the gasket or is letting air out past the gasket. Sometimes the bowl gets put on crooked and when the nut is tightened, it pushes the bottom of the bowl up some. Then, when it is put on properly, the lip in the bowl doesn't push up to seal against the gasket. To remedy this, you can use a socket or piece of dowel to put in the bowl over the raised area where the bolt goes through, and tap it with a hammer to push that raised area back down just a little.