Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Sign in to follow this  
aspeltz1

Briggs runs rough at full throttle

Recommended Posts

aspeltz1

OK guys,

The Briggs 300421 engine in my B10 just started to misfire something fierce. It idles ok but at full throttle the engine shakes, misfires, sputters, and eventually stalls. Removed carb, disassembled, cleaned everything especially main jet, and reassembled. No change. Any ideas?

Share this post


Link to post
Share on other sites
BLT

Blow back on fuel line for starts and see if that helps. If it does you probably have crud in the fuel tank. You'd be surprised how many fines sneak in the tank when re-filling.

Share this post


Link to post
Share on other sites
dentwizz

Somehow this year I have spiders in my one fuel tank}:) It was capped too.

Also check with an ignition tester(inline kind) for any coinciding spark miss issues. Sometimes a breakup can be indicated by that, either coil or plug.

Valve lash clearances can limit performance as well if it it does not perform well when warmed up but better cold. Currently fixing that on my B112.

Share this post


Link to post
Share on other sites
lugnard

Doubt it's the carb...my old auto shop teacher, who was one smart guy, told use that 90% of carb trouble is ignition! For the most part he was right. I would give it a good tune up one item at a time and see if that helps. Could be just a bad plug. I've had them spark just fine laying on top of the head but under compression will not fire. That paticular set of plugs got flung far into the weeds!!

Harry

Share this post


Link to post
Share on other sites
RickS

You stated you replaced the fuel filter, what did you replace it with. If you didn't use a filter designed for small engines that would be the cause of your problem.

Rick.......

Share this post


Link to post
Share on other sites
GrincheyOne
quote:Originally posted by dentwizz

Also check with an ignition tester(inline kind) for any coinciding spark miss issues. Sometimes a breakup can be indicated by that, either coil or plug.


id="quote">
id="quote">Briggs sells an excellent inline spark tester (works well in daylight also), $16.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Who's Online (See full list)

    • Groundhog76
    • SmilinSam
    • Tom45
    • abu507
    • tamurmueen
    • PhanDad
    • gwiseman
    • Brettw
  • Today's Birthdays

    No users celebrating today
  • Recent Status Updates

    • SonOfCreepfeed

      SonOfCreepfeed

      Thinkin' about this old girl.

      · 3 replies
    • Dean McFadden

      Dean McFadden

      Good morning peeps! I’m always searching for helpful information with my AC collection. Hope to find out new information and pass on my own experience in restoration. Here are some pics of my babies. I’m still looking for front rims for the 410 so yesterday I put the 310 wheels on took it for a drive. Working pretty good but still needs some carb work. Gotta get the 310 running next. Have a great day!😁
       

      · 1 reply
  • Adverts

×