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Brigs & Stratton mower engine won't start


layzee's Avatar
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03-23-17, 03:13 PM   #1  
Brigs & Stratton mower engine won't start

This is a B&S Gold 6.75 torque 190cc engine on a Craftsman mower. Pulled the mower out for a first cut and it won't start. Was stored with empty tank. Changed the oil and cleaned the air filter prior to attempt. Tested for spark - good. Tested for compression - good. Loosen the bolt on the bottom of the fuel bowl and fuel comes out. Removed carb and cleaned every port by running a wire through then spraying with carb cleaner then compressed air. Yes the meter jet ports on the bolt on the bottom of the bowl too. Attempted to start and nothing. Sat for a day then removed and cleaned carb again and this time testing float needle seat by blowing in fuel tube. Restricted flow with bowl down. No flow with bowl upside down. Needle and seat good. Sat for three days, pulled the cord and it started right up and ran strong for 20 seconds then died. Back to no starting. What am I missing here?

 
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03-23-17, 10:38 PM   #2  
Does it have a primer or autochoke?


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God bless!

 
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03-24-17, 08:56 AM   #3  
Hello layzee,

With the float bowl off and holding the carb up side down, is the top of the float parallel with the bowl mating surface of the carb body ?

My guess is the float needle valve seat has swelled up causing a low float level reducing the amount of fuel in the bowl, this will also reduce the size of the seat center hole so fuel can't re-fill the bowl fast enough to keep the engine running.


Good Luck,

31

 
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03-25-17, 12:50 AM   #4  
The engine has an autochoke.

I'll check the float in the am.

Bought the mower three years ago. Used first two. Sat unused third year. Wont start this year. When cleaning carb I saw very little to no gunk.

 
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03-25-17, 06:13 PM   #5  
Is the choke closed?
.......


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03-31-17, 04:17 PM   #6  
Ok. Found the float was not parallel with the carb body. Changed the needle and seat. Float was still not completely parallel but much much closer. Was that it? No. Still no start. Choke is closed. Used fresh gas this time. Considering local cliffs. Any other thoughts?

BTW - Engine model number is 126M02 6863 -FI -1205 0258

 
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03-31-17, 05:26 PM   #7  
From the engine numbers posted the bowl nut is the main jet on that carb it has one hole down the center and one across the bottom, make sure they are clean, refer to the pic below. Have a good one. Geo

[ATTACH=CONFIG]79011[/ATTACH]

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03-31-17, 05:34 PM   #8  
Yup, clean. Sprayed with carb cleaner, reamed with wire, blown out with compressed air several times. Clean as a whistle. All three holes.

 
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04-01-17, 06:28 AM   #9  
What do you consider "good" for compression and spark?
You could pull the valve cover and make sure all is still good and check your clearances.
Disconnect the kill wire from the magneto to check the kill circuit.
The only thing left is timing if you have compression, fuel and spark, valves are operating. The flywheel key sets timing.


Just needs a bigger hammer
Peace

 
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04-11-17, 11:21 AM   #10  
I'm not familiar with this mower but the problem sounds like a similar problem I'm having with a Weedeater Mower B&S engine.
Did you see if you could get this mower to start by pouring a little gas down the carburetor throat - if possible?
The other thing, I didn't see anything about checking for spark at the plug... just curious if you've made any progress or resolved the problem.
I've not worked further on my Weedeater engine yet as I have spare mower to work with but I'm suspicious of the automatic shutdown control on the spark plug being engaged without releasing the blade brake bail.
greynold99

 
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04-11-17, 03:19 PM   #11  
I just haven't had the time to deal with it these last couple weeks. I borrowed a mower and mowed my hay field so I'm good there for a while.

greynold99 - Pour gas down carb? Spose I could try that. All indications are it's getting gas ie, crack open metering bolt on bottom of fuel bowl and gas comes out plus when I try to start it I can smell gas.
Spark at plug? Yes I checked it and there's plenty of spark. Thanks for the input.

BFHFixit - Good spark? I pulled the plug, reconnected it, held it against engine case and pulled the cord. Spark was bright and consistant.
Good compression? Held thumb over spark plug hole then pulled cord. Pressure forced my thumb away and if I held it there it popped around my thumb.
Check clearances? Ya got me. Don't know what to look for.
Kill wire? I'll give it a shot.
Flywheel key? Don't know much about it. I assume it's a magnet sensed by a sensor as it rotates. How do you check it other than visually? Thanks again.

BTW - This is a CARB compliant California mower. Make any difference?

 
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