# Briggs & Stratton lopeing/hunts for idle



## evan454 (Mar 17, 2011)

it is a 1995 5HP briggs & stratton model 133202-0124-01. the engine has been starting hard and lopes/hunts. i cleaned and rebuild the carb. gaskets, diaphram. replaced the spark plug, cleaned and adjusted the magnetto, changed oil. engine starts easy now. except it still lopes/hunts. the governor is moving back and forth. it will also run smooth when i put the choke almost all the way on. turn the choke down and it starts loping again. any ideas of what the problem is??. i also cleaned the gas tank out and put fresh gas in with some seafoam and ran it for about 25 mins and no changes. if its a clogged port in the carb hopefully the seafoam will break it down but it looked pritty clean to me since i soda blasted the whole thing and soak it in almost hot water to disolve the baking soda. then i put it near a heater over night to dry it. looks brand new now. maybe something is clogged but i dont think so


----------



## chucker (Mar 18, 2011)

kind of had the same thing with mine... it about drove me crazy re did the carb ignition also ?? thought about taking up drinking but thats only a second hobbie to the first! what i did was to spray down the entire running engin with wd-40 just as a "see what happens" ?? ok !! so come to find out the danged head was lose and drew air to make it lope!! lol tigtened all the bolts to speck and no more problem!! funny as to how something so simple can change so fast... CHECK YOURS!!!!


----------



## evan454 (Mar 18, 2011)

just curious but what does spraying it with wd40 do. does it suck it in and cause it to run different


----------



## chucker (Mar 18, 2011)

yes it can make it pick up on idle speed with the intake stroke, as well as make it bubble around the base gasket on an exhaust stroke... or tell if it has a cracked head.


----------



## evan454 (Mar 18, 2011)

chucker said:


> yes it can make it pick up on idle speed with the intake stroke, as well as make it bubble around the base gasket on an exhaust stroke... or tell if it has a cracked head.


 
i will try that tomorrow since its 130 and everybody is sleeping but me


----------



## Streblerm (Mar 18, 2011)

It could also be valve adjustment or governor adjustment.


----------



## GeeVee (Mar 18, 2011)

The WD 40 is very "explosive" and spraying around gaskets might indicate leakage.

The Hunt and surge can indicate clogs or air leakage-leaning.

It may well be the throttle or shoke shafts have worn, and the air leakage sucking through the worn shaft-through-carb-body is to blame. 

The four stroke small engines with these kind of carbs can shake the shafts holding butterflys bad enough to wear out the interference fit. The carbs are not made with the highest quality pot metal.....

You indicate it has been operating regularly, and not having sat, so a carb cleaning wasn't going to reveal a stuck passage really, the other tune up items you have done are also good items to eliminate. 

I think you may have just worn out that old carb, could this be the case?


----------



## GeeVee (Mar 18, 2011)

Like mentioned above...

You may have crudded up valves that need de-carboned.

This can be done with a spray can of XXXX, but for the cost of the head gasket, you can clean and re-install with proper valve clearance.


----------



## evan454 (Mar 18, 2011)

it is very possible its just old. it is 15 years old and has its first tune up. it started this morning with 2 pulls and it ran good with the choke almost off then when it warmed up a couple mins, it started surging again. it has seafoam in it right no and it has been running at 1/2 throttle since 11:15. choke on of coarse because of the surging. but ill run it out of gas then refill with a stronger dose of seafoam. ive used seafoam in all my engines and have always got good results so hopefully this will be one of them. it ran for about 20 mins last night with seafoam so after it being off i hope it soaked up what ever crud i couldnt get because the kit came with no welch plugs.


----------



## LumberjkChamp (Mar 18, 2011)

I know you said you cleaned the carb. But, it sounds like it could be a simple matter of a clogged main jet. Take the bowl and float off, your main jet is right there. Use a pin to see if its clear.


----------



## evan454 (Mar 18, 2011)

im thinking of trying that. just waiting to let it cool down after running 2 hours. i just need to find something small enough to get in there


----------



## beavis331 (Mar 18, 2011)

I know the surging you are talking about. 9 times out of ten it is a clogged passage in the carb.(I am not saying it couldn't be a leaky intake or head) If checking the main jet as stated earlier doesn't help, I would take the carb back off and get a can of carb cleaner with the straw on it. Then spray through each and every air and fuel passage making sure when you spray in one hole it comes out in the apropriate places. I have rebuilt hundreds of carbs and that is the only sure fired way I know of to make sure all the passages are clear. Hope you get it figured out!


----------



## evan454 (Mar 18, 2011)

beavis331 said:


> I know the surging you are talking about. 9 times out of ten it is a clogged passage in the carb.(I am not saying it couldn't be a leaky intake or head) If checking the main jet as stated earlier doesn't help, I would take the carb back off and get a can of carb cleaner with the straw on it. Then spray through each and every air and fuel passage making sure when you spray in one hole it comes out in the apropriate places. I have rebuilt hundreds of carbs and that is the only sure fired way I know of to make sure all the passages are clear. Hope you get it figured out!


 
i just finished cleaning the carb with carb clean and a blow gun. the main jet, the pickup tube that goes to the bottom ofthe tank. cleaned the idle jet hole out. cleaned the 3 holes behind the biggest welch plug on the end of the carb, the best i could with out taking it out. i heated and bent the carb cleaner straw so i could get around the choke plate. all the holes i sprayed threw came out somewhere else on the carb telling me they arent plugged. i also resealed the welch plugs with clear nail polish because i notice a little bit of seepage after it running for 2 hours. hope thins all makes it better other ward it needs a new carb and its not my equipment so it will stay as it is.


----------



## brisawyer (Mar 18, 2011)

Is it this carb Parts and Diagrams for Briggs and Stratton 133202-0124-01

Get it running and try backing screw 173 out 1/2 turn


----------



## evan454 (Mar 18, 2011)

brisawyer said:


> Is it this carb Parts and Diagrams for Briggs and Stratton 133202-0124-01
> 
> Get it running and try backing screw 173 out 1/2 turn


 
it is that carb but it doesnt have the 173 screw. it has the 147 instead, which is an non adjustable screw. its all put back together perfectly clean from what i can see. still hunts. maybe its just worn out. or maybe one of the ports i cant see is plugged, hopefully fuel cleaner will help


----------



## brisawyer (Mar 18, 2011)

I hate non adjustable crap


----------



## LumberjkChamp (Mar 18, 2011)

Another thought that just occured to me is to check the governor spring. Its an old engine, so it could be stretched or otherwise worn beyond its service specs. Lots of times its that too.


----------



## GeeVee (Mar 18, 2011)

I thought you had cleaned it before, hence the worn/leaning theory.....

Hope its rips after this, for sure. 

Testament to using goggles or face mask when using carb spray and compressed air though, right?


----------



## GeeVee (Mar 18, 2011)

brisawyer said:


> I hate non adjustable crap


 
Shh- YAAAH.

Repped for that.


----------



## evan454 (Mar 18, 2011)

After all the work and $40 i put into it the only difference is that it starts right up after 3 pulls cold, 1 warm. runs smoother and doesnt quite as bad at low idle. the governor spring is a little stretched about 1/16th inch inbetween all coils. that could be the problem the the spring is not as strong and short as before. ill get a new one next week. but im all done taking the carb out. the next time i do it is getting a new carb or a whole new engine


----------



## evan454 (Mar 18, 2011)

i even torqued the head back to 140in/lb like spec. about a 1/4 turn on all


----------



## GeeVee (Mar 18, 2011)

evan454;2836955[B said:


> _]it is very possible its just old. it is 15 years old and has its first tune up._[/B] it started this morning with 2 pulls and it ran good with the choke almost off then when it warmed up a couple mins, it started surging again. it has seafoam in it right no and it has been running at 1/2 throttle since 11:15. choke on of coarse because of the surging. but ill run it out of gas then refill with a stronger dose of seafoam. ive used seafoam in all my engines and have always got good results so hopefully this will be one of them. it ran for about 20 mins last night with seafoam so after it being off i hope it soaked up what ever crud i couldnt get because the kit came with no welch plugs.



Now that I saw this and you have established the carb is clean, I would go back to the valves and carbon. Pull the plug and eyball the top of the piston. If it looks like real burnt toast..... 

Even, especially if you wind up with a new motor, cracke the ehad on it and try an figger it....


----------



## evan454 (Mar 18, 2011)

GeeVee said:


> Now that I saw this and you have established the carb is clean, I would go back to the valves and carbon. Pull the plug and eyball the top of the piston. If it looks like real burnt toast.....
> 
> Even, especially if you wind up with a new motor, cracke the ehad on it and try an figger it....


 
i have looked in threw both the spark plug, intake and exhaust ports and it is carboned up. i dont have any feeler gauges to adjust the valves though id if does need it


----------



## bobt (Mar 18, 2011)

You know I hear the "surging" sound all the time from homeowner's riding mowers. I have to assume they have the Briggs motor on them. I even hear it from push mowers with Briggs.

Is there a definitive fix for this? I would love to hear!

Bob


----------



## evan454 (Mar 18, 2011)

i hope i can find a fix it drives me crazy. its like parking driving a classic camaro etc up to a stop light and that stupid little import is revving his engine like he's got more power or something.


----------

