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B&S rebuild, new carb, won't start without starting fluid

#1

H

hcliffe

I'm trying to get an old mower running. Model is 917.377130, 6hp. It had very few hours on it, got it from an estate. I put a new carb on it from Amazon. Not sure I hooked up the linkages correctly.
If I push the primer 3 times it won't start. If I spray starting fluid in, it runs fine. I shut it off after running only briefly and have to use starting fluid again. With the throttle all the way on fast/start, shouldn't the carb door be closed to choke it? It's not doing that, its not closing no matter what position I put the throttle in. Thoughts? Is there a video or photos that show me how to hook up the linkages? I tried searching but can't find any good videos. Thanks for any help.


#2

Scrubcadet10

Scrubcadet10

okay from the diagram it appears you have a model 12 quantum engine,
Now, lets get some terminology straight, You said it has a primer, but then mention a choke door (choke plate), on these briggs, you either have a Primer and no choke, or a Choke and no primer.
So does your carb look like this one 1636495646335.png Or this one, 1636495696470.png with a throttle shaft and choke shaft?

Now, the problem could lie within the amazon carburetor, as it is not uncommon for them to sell Duds from the factory at a discounted price.
The diagram shows it originally as having a Primer/ no choke carburetor.
Anyway, to the meat and potatoes of the problem,
It is running too lean to start properly (lean mean not enough fuel), whenever you press the primer bulb, you should see fuel squirt up out of the main jet.
Craftsman 917377130 gas walk-behind mower parts | Sears PartsDirect


#3

Fish

Fish

That model, if it is the carb with the primer bulb, is known for primer problems. The problem is that the air cleaner base need to make a tight seal, as that is the passage that sends a puff of air to the carb and put up a pulse/squirt of fuel into the carb throat. I always put a smear of gasket sealant on the gasket between the air cleaner and carb, but be careful to not plug up any passages with sealant. This usually works.
If it is fixed, you will see a gush of fuel pop up when you push the bulb.


#4

H

hcliffe

Scrubcadet10 said:
okay from the diagram it appears you have a model 12 quantum engine,
Now, lets get some terminology straight, You said it has a primer, but then mention a choke door (choke plate), on these briggs, you either have a Primer and no choke, or a Choke and no primer.
So does your carb look like this one View attachment 58908 Or this one, View attachment 58909 with a throttle shaft and choke shaft?

Now, the problem could lie within the amazon carburetor, as it is not uncommon for them to sell Duds from the factory at a discounted price.
The diagram shows it originally as having a Primer/ no choke carburetor.
Anyway, to the meat and potatoes of the problem,
It is running too lean to start properly (lean mean not enough fuel), whenever you press the primer bulb, you should see fuel squirt up out of the main jet.
Craftsman 917377130 gas walk-behind mower parts | Sears PartsDirect
Click to expand...
My carb is like the first one you show. I did not replace the primer bulb, maybe I need to try that. So I should be able to look into the carb while I push the primer bulb and see fuel squirt in? Should the choke plate be closed when I try to start it? Or does this have an automatic choke?


#5

H

hcliffe

Fish said:
That model, if it is the carb with the primer bulb, is known for primer problems. The problem is that the air cleaner base need to make a tight seal, as that is the passage that sends a puff of air to the carb and put up a pulse/squirt of fuel into the carb throat. I always put a smear of gasket sealant on the gasket between the air cleaner and carb, but be careful to not plug up any passages with sealant. This usually works.
If it is fixed, you will see a gush of fuel pop up when you push the bulb.
Click to expand...
I should be able to see a gush of fuel pop up? Where would I see this? can I see it with the air filter on?


#6

Scrubcadet10

Scrubcadet10

since you have the first carb I pictured, you don't have a choke and are most likely referring to the Throttle and throttle shaft. With the engine sitting, not running, it should be wide open.


#7

H

hcliffe

Scrubcadet10 said:
since you have the first carb I pictured, you don't have a choke and are most likely referring to the Throttle and throttle shaft. With the engine sitting, not running, it should be wide open.
Click to expand...
So does the choke plate ever close? If so, when?

Thanks everyone for the input so far.


#8

S

slomo

Choke that word out of your word box. You have no choke.


#9

R

Richard Milhous

The choke depends on the muffler bearing for proper operation. Go to your nearest repair shop and ask them for a muffler bearing.


#10

S

slomo

Or a box of grid squares.


#11

Scrubcadet10

Scrubcadet10

hcliffe said:
So does the choke plate ever close? If so, when?

Thanks everyone for the input so far.
Click to expand...
on these engines the throttle plate should never fully close... if you can, post a picture of the carburetor and the linkage on your mower.


#12

Fish

Fish

The engines came with a choke or a primer capability, but with an aftermarket carb, who could know? Post a link to the carb that you bought, the old one, and the air filter assy.


#13

Fish

Fish

hcliffe said:
I should be able to see a gush of fuel pop up? Where would I see this? can I see it with the air filter on?
Click to expand...
No, you take the air filter off and look into the throat of the carb and watch, you should see a pulse of fuel pop up into the throat.


#14

H

hcliffe

Scrubcadet10 said:
on these engines the throttle plate should never fully close... if you can, post a picture of the carburetor and the linkage on your mower.
Click to expand...
Here are pics., Let me know if you need better, closer etc. Thanks!

Attachments







#15

Fish

Fish

Here it is behind the white plastic baffle.
carbthroat 001.JPG


#16

Fish

Fish

The plate that you are seeing is the throttle plate. Put up a pic of the backside of your air filter assembly and the gasket. You will notice the indentations in your old gasket, that is the path of the air pulse to the carb to prime it. If it doesn't seal well, then you won't prime the carb.


#17

Scrubcadet10

Scrubcadet10

All of your throttle linkage appears correct.
What i outlined in red is your throttle shaft and throttle plate (also called a butterfly valve, sometimes) it should sit a wide open (like it is) when the engine is not running, and close down to a little less than half way open when running.
What i outlined in green is your emulsion tube, which the main jet screws into, you should see fuel squirt out of it when you press the primer bulb.
what i circled in purple is the hole for the air impulse into the fuel bowl, which then push fuel out of the main jet.
CARB45.png

Here is the back of your airbase/primer assembly.... when you push the bulb, air follows the path i outlined in blue, and comes out the hole i circled in blue, the hole corresponds with the the hole that i circled in purple on the carburetor.
primer.png


#18

H

hcliffe

Here are pics of the air filter housing.

Attachments







#19

H

hcliffe

Scrubcadet10 said:
All of your throttle linkage appears correct.
What i outlined in red is your throttle shaft and throttle plate (also called a butterfly valve, sometimes) it should sit a wide open (like it is) when the engine is not running, and close down to a little less than half way open when running.
What i outlined in green is your emulsion tube, which the main jet screws into, you should see fuel squirt out of it when you press the primer bulb.
what i circled in purple is the hole for the air impulse into the fuel bowl, which then push fuel out of the main jet.
CARB45.png

Here is the back of your airbase/primer assembly.... when you push the bulb, air follows the path i outlined in blue, and comes out the hole i circled in blue, the hole corresponds with the the hole that i circled in purple on the carburetor.
primer.png
Click to expand...
Great diagram and explanations, thanks!


#20

Scrubcadet10

Scrubcadet10

hcliffe said:
Here are pics of the air filter housing.
Click to expand...
take a picture of the back of it, where the gasket goes.
1636568367355.png


#21

Fish

Fish

Here is a pic of a backside of one. You can see the channel that the pulse of air travels through, it must not leak air.
channel 001.JPG=-=======================


#22

H

hcliffe

Sorry for the delay, here is a picture of the back of the air filter housing. It has a new gasket I installed with the new carb.

Attachments





#23

matt man

matt man

Fish said:
That model, if it is the carb with the primer bulb, is known for primer problems. The problem is that the air cleaner base need to make a tight seal, as that is the passage that sends a puff of air to the carb and put up a pulse/squirt of fuel into the carb throat. I always put a smear of gasket sealant on the gasket between the air cleaner and carb, but be careful to not plug up any passages with sealant. This usually works.
If it is fixed, you will see a gush of fuel pop up when you push the bulb.
Click to expand...
Yea the gasket seal are notorious for leaking air, You can try double gasket too


#24

S

Sonny1980

dude you are nto alone..i literally have this same problem with every briggs and stratton mower i ever repair and find..i currently have 5 at my fathers house and had 2 befroe this and everyone whetehr the carberator was new or used had the same problem. i replaced the carberator and filter on my mothers and its the same it will only start when spraying carb cleaner into the filter..these engines are complete sheit if you ask me. even if i use the carb that comes with the engnine..same problme once they start which is firs tpull wiht the cleaner they run great but once theyre idle for an hr its the same problem all over again..its minor but irritating as id like to have them perfect..and literally no-one wants to tell me whats wrong or they claim to have no idea why this is..clearly im not the only one with this issue its the designers ..no-one carews to answer why this is because they want to know something you dont. i get the feeling they know they just ownt tell you


#25

Scrubcadet10

Scrubcadet10

What happens is people tighten the airfilter base too tight and it becomes warped, the primer passage doesn't seal good, so the air goes out the warped parts instead of following the passage into the carburetor.
It can also warp from heat and other elements.


#26

N

njtinman2001

Finnegan pin


#27

H

hlw49

Sonny1980 said:
dude you are nto alone..i literally have this same problem with every briggs and stratton mower i ever repair and find..i currently have 5 at my fathers house and had 2 befroe this and everyone whetehr the carberator was new or used had the same problem. i replaced the carberator and filter on my mothers and its the same it will only start when spraying carb cleaner into the filter..these engines are complete sheit if you ask me. even if i use the carb that comes with the engnine..same problme once they start which is firs tpull wiht the cleaner they run great but once theyre idle for an hr its the same problem all over again..its minor but irritating as id like to have them perfect..and literally no-one wants to tell me whats wrong or they claim to have no idea why this is..clearly im not the only one with this issue its the designers ..no-one carews to answer why this is because they want to know something you dont. i get the feeling they know they just ownt tell you
Click to expand...
To quote Scrub " What happens is people tighten the airfilter base too tight and it becomes warped, the primer passage doesn't seal good, so the air goes out the warped parts instead of following the passage into the carburetor.
It can also warp from heat and other elements."

Replace the air cleaner base and torque the screws as per the instructions.


#28

H

hcliffe

matt man said:
Yea the gasket seal are notorious for leaking air, You can try double gasket too
Click to expand...
I used a double gasket since I had the old one. I pushed the primer and could see gas squirting in. It starts now with just using the primer and not the starting fluid. Thanks much everyone!


#29

Scrubcadet10

Scrubcadet10

Great! thanks for letting us know.


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