Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies

smkyle

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Hello and thank you for viewing my post.

I have a Snapper mower with a 675 series Briggs and Stratton engine. I hope these are the needed numbers

Model Number P2167520B 21" Walk Behind
Engine Family 9BSXS.1901VH 278643
Engine 126T02-0267-B1 0902 1157
EPA 278643

I inherited the mower from my sister. It is 5 years old and did not receive regular maintenance. The mower stopped maintaining a constant speed and would die after about 15 minutes so I tried to tune it up to get it working. I know nothing about small engines other than what I learned in the process of trying to get this mower to work properly. Here is what I have done:

Replaced the spark plug and adjusted the gap to factory specifications
Added oil (I did not change the oil and I'm not sure how)
Replaced the pre-filter and air filter
Replaced a spring and trimmed a different spring that move the throttle properly? (not sure if I'm describing this right)
Removed the carburetor cup and cleaned that and the nut with compressed air and carburetor cleaner, then blew compressed air and sprayed carburetor cleaner into the carburetor.
Removed the fuel line and checked it for clogs. I did not clean it

Here are some other things about the engine:

I did not see a carburetor adjustment screw
There is no primer
There is no fuel filter
The gas cap does not have a hole in it

I replaced the spark plug. Then, after every tune-up step I would try to mow again. The air filter made zero difference. I adjusted the springs because the throttle lever near the handle was not changing the engine speed. As near as I can tell the lever is now behaving the way it should. However, I didn't know what I was doing so that is a potential issue. At first it appeared to be the fix and the throttle increased/decreased the engine speed. I was able to mow for about 5 minutes and then the engine died. Then I tried the carburetor. The mower hasn't worked since. I can get it to start if I leave it alone for a while but it barely idles and then dies. While attempting to idle it blows out a lot of smoke. I made sure there is a spark.

My guess is that there is a fuel/air mixture problem. HELP!!! Any suggestions are appreciated.
 
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RayInTn

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Re: Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies

Hello and thank you for viewing my post.

I have a Snapper mower with a 675 series Briggs and Stratton engine. I hope these are the needed numbers

Model Number P2167520B 21" Walk Behind
Engine Family 9BSXS.1901VH 278643
Engine 126T02-0267-B1 0902 1157
EPA 278643

I have the 6.75 Briggs on my Cub Cadet src 621 which I also inherited. Believe it or not mine also smoke heavily when I got it. I found that the previous owner had overfilled the oil by about 5 ounces. This Briggs has a capacity of 18 ounces. You can buy bottles of pre-measured 30w oil at most lawn implement or auto parts stores. I actually bought Briggs and Stratton oil at Walmart. The oil is drained through a plug on the underside of the engine. After you clean the grass clippings and dirt off you should see a plug with a square hole in it. The hole is the same size as the square end of a 3/8 socket extension. It will slip right in and can be turned with a ratchet. If the mower has not been maintained well the drained oil will probably be diluted with gas. Good idea to change it anyway. Also plan on getting another sparkplug. Oil fouled plugs are hard to clean properly. Good luck.
 

DaveTN

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Re: Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies

Try taking off the carburetor bowl and clean it out. I use a 1/2" box end wrench, although a small socket might work if you have enough room under it. Drain all the gas out and check where the fuel line goes into the carb. Spray it out in there, see if any dirt, rust, etc. comes out. Watch your eyes! That carb cleaner is rough on the eyes!! Squirt carb cleaner up in and around where the bowl fits on the carb, work the float and needle by hand while squirting it as well. Squirt up in the center part where the bolt holds the bowl on. Probably fuel starvation issue. Those throttle and governor linkages work as follows: The throttle SPRING pulls the engine INTO FUEL. The GOVERNOR (solid link) pulls the engine OUT OF FUEL. The balance point is the RPM.
 

smkyle

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Re: Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies

Try taking off the carburetor bowl and clean it out. I use a 1/2" box end wrench, although a small socket might work if you have enough room under it. Drain all the gas out and check where the fuel line goes into the carb. Spray it out in there, see if any dirt, rust, etc. comes out. Watch your eyes! That carb cleaner is rough on the eyes!! Squirt carb cleaner up in and around where the bowl fits on the carb, work the float and needle by hand while squirting it as well. Squirt up in the center part where the bolt holds the bowl on. Probably fuel starvation issue. Those throttle and governor linkages work as follows: The throttle SPRING pulls the engine INTO FUEL. The GOVERNOR (solid link) pulls the engine OUT OF FUEL. The balance point is the RPM.

Thank you for the response. Assuming the carburetor is cleaned properly, could the tension of the springs be the cause of fuel starvation?
 

smkyle

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Re: Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies

Hello and thank you for viewing my post.

I have a Snapper mower with a 675 series Briggs and Stratton engine. I hope these are the needed numbers

Model Number P2167520B 21" Walk Behind
Engine Family 9BSXS.1901VH 278643
Engine 126T02-0267-B1 0902 1157
EPA 278643

I have the 6.75 Briggs on my Cub Cadet src 621 which I also inherited. Believe it or not mine also smoke heavily when I got it. I found that the previous owner had overfilled the oil by about 5 ounces. This Briggs has a capacity of 18 ounces. You can buy bottles of pre-measured 30w oil at most lawn implement or auto parts stores. I actually bought Briggs and Stratton oil at Walmart. The oil is drained through a plug on the underside of the engine. After you clean the grass clippings and dirt off you should see a plug with a square hole in it. The hole is the same size as the square end of a 3/8 socket extension. It will slip right in and can be turned with a ratchet. If the mower has not been maintained well the drained oil will probably be diluted with gas. Good idea to change it anyway. Also plan on getting another sparkplug. Oil fouled plugs are hard to clean properly. Good luck.

Thank you, I may revisit the oil issue once I can get the engine to idle. The smoke problem is hard to diagnose when the engine doesn't run =) I mentioned it because I thought it might indicate that there is too much fuel or fuel in the wrong place.
 

churchbuilder

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  • / Snapper with 675 series Briggs & Stratton engine sometimes starts but then dies
Have you tried cleaning your gas cap? If you remove the gas cap will it keep running? They are vented caps that get dirty and cause the engine to starve for gas.
 
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