Outdoor Power Equipment and Small Engines - B&S Troubles

OK here goes. 2 years ago I developed a problem with my B&S mower with a preset carb.. The engine would surge constantly, but never reach full power. As I would mow, the mower would generate less and less power until it eventually quit. However, it would start right up. I got frustrated enough that I took it to someone in town who tuned it up for $50. Half of what I paid for the mower new. THat was 2 years ago. Yesterday I was mowing and had to stop to move to a new section of the yard. When I started the mower I heard/felt a snap/pop and the very same problem occurred: surging. What gives? I assume since the problem started all at once that there isn't a problem with a blocked carb. Any thoughts?

It does sound like the surging could be a fuel restriction especially if your carb has no adjustments. Start with the fuel delivery, Tank cap vent, fuel tank, lines, filter. If a problem is not found there, its still most likely an easy fix but will help with model #'s of your mower and engine.
You can pull the fuel line at the carb also and make sure you are getting ample supply, if so, you can disconnect the fuel supply plug or secure the line. On the bottom of the carb should be a little can with a bolt in the bottom center. Remove the bolt (1/2" head) and the can check for debris and clean. The bolt may also have passages that need to be checked and cleaned.
If you still have problems post back with some model #'s.

Engine ID #'s please!!! Still is likely carb related but could be valve issues since you mentioned a "pop".

The motor is a 3.5 hp that is on a 20" Murray. I believe the model number is YBSXS 1581VA 274460. At least that is what was on the sticker on the gas tank.

Thanks for your help!

The #'s provided are not what we need. The numbers will be stamped into the flywheel shroud, either above the spark plug or above the muffler.

Gotcha. As best as I can make them out the numbers are:
9D902 2005 B2 00031552.

Is that what you needed?

is ti a 22-inch cut with 4 small wheels. if it is, just remove and cleane the carb bowl and there is a piece that is red or pinkish, gently move thatpiece up and down and fuel should come out a little bit, if it does your a okay. Note: make sure you empty the tank as much as possible or you and your lawnmower will be covered in gasoline. good luck and let us know how it goes. i had the same probelm with my 6.0 hp B&S and it works fine now.

You have a diaphragm and primer style carburetor. Simple enough to repair youself. Remove the air cleaner by way of a single screw, remove two screws (bolts) which hold the carb/tank assembly to the engine (you will have to deal with a governor linkage to get the carb/tank off - self-explanitory, just make a note of the hole from which you take the link out of at the carb), remove the four screws which hold the carburetor to the tank, replace the gasket and diaphragm with Briggs part # 495770. Reassemble and you should be good. Let us know how it goes!

After winter period the machine started fine then "coughed" a lot and stopped as if it had not "gas" enough. Pumping all the time to prime kept the engine alive but it was impossible to cut the grass this way.

Then i searched over the web and came to your site and wow the revelation.

Could it be so simple, will i be able to repair myself?

And thanks to puey61 i did my first reparation and my lawnmower works as new now.

I've just replaced gasket and diaphragm with Briggs part # 495770 and it works!
Thanks to everybody in this forum and particulary to puey61 who's explanation was clear and simple to follow.

My pleasure, andrejs, and glad you made a successful repair. Bookmark us so you are just a mouseclick away!

Here are the numbers you'll need to help:

10A902 (Listed 1st)
Type: 2180 B1
Code: 00062355

History thus far: I've removed the gas tank and carb, cleaned all the micro-screens used for the fuel. I cleaned the plug, removed the air cleaner to ensure that it's getting plenty of air. Checked and filled both oil and gas.

First Issue: As I was reassembling I noticed that the smaller of the two spring ends that regulate the throttle broke. I thought I looked closely to see how they were hooked up but I'm at a loss as to where the end that broke needs to be reattached. (I probably need a new one since the spring rate will not be the same).

Second Issue: A previous post indicated that I may need to replace a gasket and diaphragm. I'm guessing that the diaphragm is located between the carb and the gas tank? I need to know what gasket needs to be replaced and where it's located.

Lastly I am unclear as to the purpose of the rocker arm that the springs attach to. It only pivots about 1/4" Would you enlighten me on that too please?

You can enter model 10a902 type 2180 in boxes at following site and download IPL for your model:
https://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?category=Engines&manual_type=Illustrated%20Parts%20Lists&menu=nav3&subMenu=3
Page 4 shows carb breakdown. Ref 394 shows the gasket and diaphragm. Diaphragm sits on top of tank, then the gasket.
hope this helps,
thanks,

Very much appreciated thank you!

After winter period the machine started fine then "coughed" a lot and stopped as if it had not "gas" enough. Pumping all the time to prime kept the engine alive but it was impossible to cut the grass this way.

Then i searched over the web and came to your site and wow the revelation.

Could it be so simple, will i be able to repair myself?

And thanks to puey61 i did my first reparation and my lawnmower works as new now.

I've just replaced gasket and diaphragm with Briggs part # 495770 and it works!
Thanks to everybody in this forum and particulary to puey61 who's explanation was clear and simple to follow.

if it can't be solved on this forum, from what i've see, it really isn't possible.GOOD INFO.!

Model: 10A902
Type: 2180 B1
Code: 00062355

As I was reassembling I noticed that the smaller of the two spring ends that regulate the carb broke. I thought I looked closely to see how they were hooked up but I'm at a loss as to where the end that broke needs to be reattached. (I probably need a new one since the spring rate will not be the same).

Would anyone be willing to send a picture of how these two springs should be attached? Please send a private note and I'll give an e-mail address to which a .jpg can be attached. (This model is self-governing ie: no throttle cable so what I need is a photo showing the two springs that regulate the carb.)

Thanks!

The governor spring for you engine is #690251(Yellow) and the governor idle spring is #691859. Sorry I don't have pictures for the hookup, your best bet would be to go to a Big Box store that sells something similar and see how they are hooked up. Have a good one. Geo

Thanks for the P/N's and the idea (and excuse) to snoop at the local Lowes!