B & S Engine Mower Running Rough

[Kennykenny]

I'll stay tuned. Whatever you do, don't assume that my list is too hard because it covers the whole page. :laughing:

Primer,

I am working my way through your list. The diagnosis is going well. All looks goog thus far. Is it possible to give more detailed how to insturctions on how to do the checks on steps 8-10? I am not sure of some of the items that you are describing and how to proceed through these steps. Thank you.

8. Inspect the intake tube (plastic tube from carb to engine) and ensure that it is free of cracks. Make sure the bolts holding it to the engine are not loose. You will have to remove the metal shroud to do this.

9. While you have the metal shroud removed, make sure there is no debris preventing the governor and throttle linkage from operating properly.


10. Inspect the head gasket to make sure it's not blown. Ensure that all cylinder head bolts are tight.

 

[primerbulb120]

Primer,

I am working my way through your list. The diagnosis is going well. All looks goog thus far. Is it possible to give more detailed how to insturctions on how to do the checks on steps 8-10? I am not sure of some of the items that you are describing and how to proceed through these steps. Thank you.

8. Inspect the intake tube (plastic tube from carb to engine) and ensure that it is free of cracks. Make sure the bolts holding it to the engine are not loose. You will have to remove the metal shroud to do this.

9. While you have the metal shroud removed, make sure there is no debris preventing the governor and throttle linkage from operating properly.


10. Inspect the head gasket to make sure it's not blown. Ensure that all cylinder head bolts are tight.

I've got to run now, but I'll give you more details after dinner. :thumbsup:

 

[Kennykenny]

I've got to run now, but I'll give you more details after dinner. :thumbsup:

:thumbsup:

 

[primerbulb120]

Okay, so judging by your pictures you already have the decorative plastic shroud off. Now you need to remove the metal shroud that covers the flywheel and cylinder. In order to do this, first you need to take off the gas tank. There are 4 bolts holding it on, 3 around the starter and one under the gas tank at the back of the engine. (It's on the carb side of the engine.) With the bolts removed, clamp the fuel line with a vice grips and disconnect it from the carburetor. Then you should be able to lift the gas tank off the shroud.

After removing the gas tank, you can remove the metal shroud. There are 5 bolts holding it on. Two are at the front of the engine, above the spark plug. Two are at the very back, holding the shroud onto the engine block. The other one holds the oil disptick on. Remove it and then rotate​ the dipstick assembly to get it out of the way. (It's just held onto the engine block by an O ring, so it should rotate easily. ) After this, you can pull the metal shroud off.

With the shroud removed, you will be able to access all the parts in steps 8 and 9. The plastic intake tube goes from the carburetor to the engine. Make sure it is in good shape and the bolts holding it to the engine are not loose.

You will also be able to see the governor linkage (number 9.) It consists of the parts connected to the throttle. Make sure it's free of debris and moving freely.

Step 10 is the head gasket. It's the gasket between the cylinder head and the engine. The cylinder head is the part that the spark plug screws into. The head bolts are the bolts around the spark plug. Make sure the head gasket doesn't have any obvious leaks or holes in it. Don't take the cylinder head off, just do the best you can with it attached.

 

[Kennykenny]

Okay, so judging by your pictures you already have the decorative plastic shroud off. Now you need to remove the metal shroud that covers the flywheel and cylinder. In order to do this, first you need to take off the gas tank. There are 4 bolts holding it on, 3 around the starter and one under the gas tank at the back of the engine. (It's on the carb side of the engine.) With the bolts removed, clamp the fuel line with a vice grips and disconnect it from the carburetor. Then you should be able to lift the gas tank off the shroud.

After removing the gas tank, you can remove the metal shroud. There are 5 bolts holding it on. Two are at the front of the engine, above the spark plug. Two are at the very back, holding the shroud onto the engine block. The other one holds the oil disptick on. Remove it and then rotate​ the dipstick assembly to get it out of the way. (It's just held onto the engine block by an O ring, so it should rotate easily. ) After this, you can pull the metal shroud off.

With the shroud removed, you will be able to access all the parts in steps 8 and 9. The plastic intake tube goes from the carburetor to the engine. Make sure it is in good shape and the bolts holding it to the engine are not loose.

You will also be able to see the governor linkage (number 9.) It consists of the parts connected to the throttle. Make sure it's free of debris and moving freely.

Step 10 is the head gasket. It's the gasket between the cylinder head and the engine. The cylinder head is the part that the spark plug screws into. The head bolts are the bolts around the spark plug. Make sure the head gasket doesn't have any obvious leaks or holes in it. Don't take the cylinder head off, just do the best you can with it attached.

Great instructions. I will check it out and let you know. Thank you!

 

[Kennykenny]

Okay, so judging by your pictures you already have the decorative plastic shroud off. Now you need to remove the metal shroud that covers the flywheel and cylinder. In order to do this, first you need to take off the gas tank. There are 4 bolts holding it on, 3 around the starter and one under the gas tank at the back of the engine. (It's on the carb side of the engine.) With the bolts removed, clamp the fuel line with a vice grips and disconnect it from the carburetor. Then you should be able to lift the gas tank off the shroud.

After removing the gas tank, you can remove the metal shroud. There are 5 bolts holding it on. Two are at the front of the engine, above the spark plug. Two are at the very back, holding the shroud onto the engine block. The other one holds the oil disptick on. Remove it and then rotate​ the dipstick assembly to get it out of the way. (It's just held onto the engine block by an O ring, so it should rotate easily. ) After this, you can pull the metal shroud off.

With the shroud removed, you will be able to access all the parts in steps 8 and 9. The plastic intake tube goes from the carburetor to the engine. Make sure it is in good shape and the bolts holding it to the engine are not loose.

You will also be able to see the governor linkage (number 9.) It consists of the parts connected to the throttle. Make sure it's free of debris and moving freely.

Step 10 is the head gasket. It's the gasket between the cylinder head and the engine. The cylinder head is the part that the spark plug screws into. The head bolts are the bolts around the spark plug. Make sure the head gasket doesn't have any obvious leaks or holes in it. Don't take the cylinder head off, just do the best you can with it attached.

Primer,


I have followed all of your steps(except for the inline spark tester-don't have one). Everything looked to be in good shape. I have cleaned up everthing that I could. Unfortunately I can not even get the mower to start now. I sprayed some carb cleaner in the carb and the mower tries to but does not. No carb cleaner, no luck at all attempting to start.

You previously asked when this started to happen, it began last fall, when mowing, but has continued this spring and I decided that it was time to address the problem. You also mentioned, a sheared flywheel key, bad carburetor or valves not seating properly. Are you still leaning toward those issues? If so, other than replacing with a new carb, how do I go about repairing the other two items? Thoughts?

 

[primerbulb120]

If it tries to starts and stalls with the carb cleaner but won't start at all without it, it must be a carb issue. I would replace the carb and see if that fixes it. You really don't want to get into the cylinder to check the valves unless it's absolutely necessary, as you're supposed to have a torque wrench to tighten the head bolts during reassembly. Checking the flywheel key is a difficult job as well.

Don't buy a carb just yet, let me look one up for you. You have to be careful as there are lots of junk Chinese carbs out there.

 

[Kennykenny]

If it tries to starts and stalls with the carb cleaner but won't start at all without it, it must be a carb issue. I would replace the carb and see if that fixes it. You really don't want to get into the cylinder to check the valves unless it's absolutely necessary, as you're supposed to have a torque wrench to tighten the head bolts during reassembly. Checking the flywheel key is a difficult job as well.

Don't buy a carb just yet, let me look one up for you. You have to be careful as there are lots of junk Chinese carbs out there.

Thanks so much!

 

[unluckywithmowers]

Hi, I definitely don't want to divert from this thread, especially since it sounds like you're getting pretty far along, but I think I'm having similar problems.
I submitted my problem as a new post.
I'm also certainly following your thread very closely. If it seems like there might be some overlap or any wisdom, I'd appreciate a look. I do seem to have a bit more success with the starting, but less success with the continued running. Happy to provide any other details anyone thinks might inform this thread in any way.

Thanks!

 

[primerbulb120]

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.)?