B & S Engine Mower Running Rough

[Kennykenny]

If you decide to go with a new carburetor, here's the one I would get: https://www.amazon.com/Briggs-Stratton-799866-Carburetor-Replaces/dp/B00CNWWNGW

Might be worth a shot to try troubleshooting the old one before spending $32 on a new one, since I'm not 100% sure that the carb is your issue. As far as what's wrong with the current one, I'd suspect either the float or the needle seat. This is assuming that

- The gas tank contains fresh, new gas.
- The fuel line is not obstructed.
- The carburetor has been thoroughly cleaned otherwise.

When I clean/rebuild a carburetor of this type, I typically replace the following parts:

- Float
- Needle valve
- Both bowl gaskets
- Needle seat

These parts can be obtained by purchasing the following two kits:

http://www.ebay.com/itm/WALBRO-OEM-...ash=item41c3856d73:m:mitMQjpy0Jjt171UugWDZVA\
http://www.ebay.com/itm/GENUINE-Wal...960839?hash=item3f44211e87:g:A08AAOSwdIFX0dFG

Thanks for posting the history of the problem! Did it appear over time, did it appear all at once while mowing, or did it begin between mowings (mower ran fine one week and wouldn't start the next.)?

Is it just as cost effective to purchase a new carb vs buying pieces?

 

[primerbulb120]

Around $12-$15 for the parts, $32 for a new carb.

 

[primerbulb120]

With your situation, after considering it some more I would recommend the new carb. With the new carb there's no chance something else in the carb is clogged or broken. :thumbsup: And you also have to consider the labor involved to fix the old carb.

If you were closer, I would tell you to go and pull the carb off the running Toro Recycler behind my shop and put it on yours to see if that fixes it. Unfortunately you live too far away. :frown:

 

[Kennykenny]

With your situation, after considering it some more I would recommend the new carb. With the new carb there's no chance something else in the carb is clogged or broken. :thumbsup: And you also have to consider the labor involved to fix the old carb.

If you were closer, I would tell you to go and pull the carb off the running Toro Recycler behind my shop and put it on yours to see if that fixes it. Unfortunately you live too far away. :frown:

I agree with your idea about the labor of a new one vs rebuilding and piecing an old one. To answer some of your followup questions:

Did it appear over time(Yes did appear over time), did it appear all at once while mowing(No), or did it begin between mowings (mower ran fine one week and wouldn't start the next.)-(No, once it started to run poorly--surging fast and slow, fast and slow, it has continued since).

- The gas tank contains fresh, new gas.--Yes I have put in new gas and oil when I went through your diagnosis checklist
- The fuel line is not obstructed.---assuning that the fuel line is the rubber hose from the gas tank to the side if the carb--no, it is clear, I checked that.
- The carburetor has been thoroughly cleaned otherwise.---cleaned well twice.

 

[Kennykenny]

If you decide to go with a new carburetor, here's the one I would get: https://www.amazon.com/Briggs-Stratton-799866-Carburetor-Replaces/dp/B00CNWWNGW

Might be worth a shot to try troubleshooting the old one before spending $32 on a new one, since I'm not 100% sure that the carb is your issue. As far as what's wrong with the current one, I'd suspect either the float or the needle seat. This is assuming that

- The gas tank contains fresh, new gas.
- The fuel line is not obstructed.
- The carburetor has been thoroughly cleaned otherwise.

When I clean/rebuild a carburetor of this type, I typically replace the following parts:

- Float
- Needle valve
- Both bowl gaskets
- Needle seat

These parts can be obtained by purchasing the following two kits:

http://www.ebay.com/itm/WALBRO-OEM-...ash=item41c3856d73:m:mitMQjpy0Jjt171UugWDZVA\
http://www.ebay.com/itm/GENUINE-Wal...960839?hash=item3f44211e87:g:A08AAOSwdIFX0dFG

Thanks for posting the history of the problem! Did it appear over time, did it appear all at once while mowing, or did it begin between mowings (mower ran fine one week and wouldn't start the next.)?

The link that you provided for the carb led me to a used carb. I am assuming that it is not the one that you were suggesting? I saw the following one on Amazon for $32, https://www.amazon.com/Briggs-Strat...tton+799866+Carburetor+Replaces+796707+794304

Is this the new one that you were suggesting?

 

[BRYANB]

I have a Toro push mower 20332 that has a B & S engine 6.75 HP. I am having a problem getting the engine to start and then when it does start it runs rough. I have disassembled the carburetor and cleaned it thoughly and reassembled it. The spark plug is good and has been changed.

Any suggestions on anything else to try or what the problem could be?

DOES IT HAVE THE BOWL WITH THE FLOAT OR DOES IT HA A DIAPHRAM

 

[BRYANB]

IF IT HAS THE BOWL WITH THE FLOAT CHECK THE NEEDLE AND SEAT BUT I THINK IT'S THE BREATHER IN THE BOLT THAT HOLDS THE BOWL IT HAS BREATHER HOLES I CLEAN MINE WITH A PAPER CLIP OR AN OLD BREAD TIE

 

[Kennykenny]

IF IT HAS THE BOWL WITH THE FLOAT CHECK THE NEEDLE AND SEAT BUT I THINK IT'S THE BREATHER IN THE BOLT THAT HOLDS THE BOWL IT HAS BREATHER HOLES I CLEAN MINE WITH A PAPER CLIP OR AN OLD BREAD TIE

It has the float etc. I have cleaned the holes of the bolt a couple of times with no change.

 

[primerbulb120]

The link that you provided for the carb led me to a used carb. I am assuming that it is not the one that you were suggesting? I saw the following one on Amazon for $32, https://www.amazon.com/Briggs-Strat...tton+799866+Carburetor+Replaces+796707+794304

Is this the new one that you were suggesting?

That's weird, when I click the link it gives me a new one. :confused2: The one I was recommending is part number 799866. Price is $32.12.

This engine really has me confused. It's got to be the carb, valves or flywheel key, but I'm not sure which one is the problem. :confused2:

My first guess is carb for the following reasons:

- Valves on these engines typically don't go out of adjustment. Neither have I encountered many of these engines with sticking valves.

-Flywheel keys typically don't shear for no reason. Normally they shear after you hit something with the mower, and a sheared key typically causes sharp kickback when you try to start the engine.

 

[BRYANB]

It has the float etc. I have cleaned the holes of the bolt a couple of times with no change.

HOW OLD IS THE GAS CAP SOMETIMES THEY CANT BREATH AN CAUSES A VAPOR LOCK