Briggs & Stratton Experts:Surging ?

[monkeyspunk79]

Okay, so I know little about small engines other than they're...a small engine. I have a 3 or 4 year-old Murray mower with a 3.75 horse Briggs on it. The mower is great except recently it started surging and I can't figure out how to fix it. It doesn't have a throttle adjuster, its one of those carbs that has two springs & a butterfly that seems to 'adjust itself' but something is clearly wrong. I took of the air cleaner and shot some Gumout in there and it helped for about 2 minutes...then the throttle returns to bouncing up and down. Its extremely annoying.

Since it was only a $120 mower I don't think its worth spending $75 on a shop to fix it. Any suggestions on what may be the culprit?

Thanks in advance.

 

[DHG BULLITT]

I sell lawn and garden equipment at Sears. Most places are going to charge you $30-$50 just to look at it. Most small single stroke motors surge a bit to begin with. Try tightening the kill cable that runs to your bail handle it may be lose and trying to cut off power air to the motor.

Try replacing the air filter and spark plug as well.

 

[BuckChoklit]

YouTube - Davidsfarm's Channel

If that doesn't help, search through his other videos. He's got a few on how to fix Briggs engines.

 

[juzlookzfazt]

I sell lawn and garden equipment at Sears. Most places are going to charge you $30-$50 just to look at it. Most small single stroke motors surge a bit to begin with. Try tightening the kill cable that runs to your bail handle it may be lose and trying to cut off power air to the motor.

Try replacing the air filter and spark plug as well.

That makes us technically brothers lol. I do the same, except in O-town, FL.

 

[TERMIN8TR]

take the carb off and open it up and clean it real good.

 

[Junior00]

take the carb off and open it up and clean it real good.

Bingo, it's all in the carb. Remove it, disassemble and soak overnight. Buy a rebuild kit if you need to, but in most cases it's just gummed up.

 

[DHG BULLITT]

take the carb off and open it up and clean it real good.

Bingo, it's all in the carb. Remove it, disassemble and soak overnight. Buy a rebuild kit if you need to, but in most cases it's just gummed up.

If he took the air cleaner off and shot gumout in it he basically did. There isn't much more to cleaning the carb on most briggs. Definitely no point in pulling it off the motor.

 

[DHG BULLITT]

That makes us technically brothers lol. I do the same, except in O-town, FL.

Right on man, it does a decent job of paying off school loans, can't complain.

 

[Junior00]

If he took the air cleaner off and shot gumout in it he basically did. There isn't much more to cleaning the carb on most briggs. Definitely no point in pulling it off the motor.

Gumout is okay, but does not do very well on hard deposits and stubborn build up. Take into account the fact that it is a diaphragm type carb. The screen could have crap in it, the pick-up tube probably has deposits and could even be cracked, the seals have probably dried out and cracked or are non-existant, the orifices are clogged and most importantly the diaphragm needs to be changed along with the springs. Removing it & thoroughly cleaning it as well as replacing all the old parts with a new $7 kit is not only the smart move but the correct one and takes a small amount of time.

OP, you mentioned it is on a murray...22" deck I assume, though there are a few variations this should be close. Double check your model number and order a carb kit.
http://www.briggsandstratton.com/ma...docmanualdetails.aspx?showpdf=MS0235_B_LO.pdf

*And yes I've rebuilt more than my fair share of B&S engines in my time

 

[TERMIN8TR]

If he took the air cleaner off and shot gumout in it he basically did. There isn't much more to cleaning the carb on most briggs. Definitely no point in pulling it off the motor.

No that's wrong. It has to come off disassembled and thoroughly cleaned.

 

[monkeyspunk79]

Thanks for the advice everyone, I think I will start with taking the carb off, cleaning the screens & checking things, and replacing the diaphragm. I think with the owner's manual, and that video from Dave's Farm (great stuff on there BTW) I should be good to go.