B & S 28B707 issues

Bas_NL

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I have a Husqvarna lawn mower with a B & S 28B707 motor. Yesterday I mowed the lawn and after ~20 minutes the motor occasionally started to stutter. I'm not sure but I have the feeling that it became worse after a while. The engine works fine for a little while and then suddenly almost stalls and goes back to functioning normal again. I opened the fuel cap during mowing but I didn't notice any difference.

Today I cleaned the air filter and added little oil. I then started the motor and let it run on "full throttle". At first it ran fine but after a minute or so the same problems occurred. At low throttle / idling it stops running after ~10 seconds. After it stopped I can start it again without any problems.

Any idea what might cause this issue?
 

Born2Mow

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Year model and number of hours would really help.

Suggestions (no particular order):
  • Running too hot. Pull the air cowling and clean off the tops of the cylinder(s).
  • Try fresh gas.
  • Take a spare plug with you and see if the spark goes away right when this event is happening.
  • Have the coil tested.
 

slomo

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I have a Husqvarna lawn mower with a B & S 28B707 motor. Yesterday I mowed the lawn and after ~20 minutes the motor occasionally started to stutter. I'm not sure but I have the feeling that it became worse after a while. The engine works fine for a little while and then suddenly almost stalls and goes back to functioning normal again. I opened the fuel cap during mowing but I didn't notice any difference.

Today I cleaned the air filter and added little oil. I then started the motor and let it run on "full throttle". At first it ran fine but after a minute or so the same problems occurred. At low throttle / idling it stops running after ~10 seconds. After it stopped I can start it again without any problems.

Any idea what might cause this issue?
Are you not checking your oil level prior to every mow? If not you better start. Check the oil and add fuel prior to mowing.

Dump the fuel tank and clean it out like below.

Clean your carburetor in the wife's dishwasher. Remove all plastic and rubber parts. Put on hot pot scrubber mode. Will come out like new.

Have you ever removed the engine cowl and cleaned all the mud, grass, oil, bugs and grit off the cylinder cooling fins? Might want to add this to your yearly maintenance. It's in your engine manual. Clean ALL THE WAY AROUND each cylinder.

Mr-Clean-Logo-600x600.jpg
 

StarTech

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Last time I used pot scrubber mode on a dish washer I about got killed.


Mt mother's iron skillets came out rusted as I also used heated drying. I was dodging the flying frying pans...
 

slomo

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Last time I used pot scrubber mode on a dish washer I about got killed.


Mt mother's iron skillets came out rusted as I also used heated drying. I was dodging the flying frying pans...
You are not supposed to wash a cast iron skillet. Simply wipe out with a cooking oiled paper towel. You remove the black coked oil film that becomes non-stick. Best pan on Earth is the old tried and true cast iron pan. Best durability, heat holding champ, non warping, non-stick and has the best flavor of any pan. I hope your wife beat the snot out of you for doing that. Good for her!!!! (y) :D

slomo
 

Hammermechanicman

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Last time I used pot scrubber mode on a dish washer I about got killed.


Mt mother's iron skillets came out rusted as I also used heated drying. I was dodging the flying frying pans...
Dude! You put a cast iron skillet in a dish washer?????? In some southern states that IS a capital offense. I have a 12" Griswold that is very old but it is warped and won't sit flat on the electric stove so i went to a 12" Lodge that is about 20 years old now. Just about got it seasoned where i want it.
 

slomo

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Last time I used pot scrubber mode on a dish washer I about got killed.


Mt mother's iron skillets came out rusted as I also used heated drying. I was dodging the flying frying pans...
Just think if the wife put your ratchets and air tools in her dishwasher. What a meathead LOL o_O:D

slomo
 

Bas_NL

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Thanks for the answers. It is an Rider 11 Bioclip, no idea about the age/hours but it certainly is an older machine. I guess that it is at least 15 years old.

When I was searching for the coil I noticed a wire were the insulation was was rubbed of. I put some heat shrink around it and tested the engine again. It now runs much better and doesn't stall anymore. But it still stutters a bit.
We put fresh gas in it about two weeks ago, before that the tank was empty. After that we did mow the lawn 2 times without any problems, the 3rd time the problems began.

@slomo, no I don't check the oil every time I mow the lawn. Seen the issues we now face I assume cleaning the carburetor is still a good thing to do?
 

StarTech

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Just think if the wife put your ratchets and air tools in her dishwasher. What a meathead LOL o_O:D

slomo

You know a 10 yr old isn't the sharpest tack in box but we do learn.

Wife? What that? 62 yrs single and out to stay that way. No point getting hen peck now
 
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