Surging

[vipermanz]

i have a 4hp briggs that seems hellbent on surging up and down.

i've: changed gas, spark plug, air filter, and still no change.

i request the help of some one else.
:( :confused: :(

[Turfdude]

Check/clean /replace fuel filter?? Maybe a small hol in gas line somewhere, look at a few other smple solutions.

Bob

[Remo Sid]

I have saw this problem addressed in several different forums, and have did a lot of research. Although some swear by certain remedies none seem to work with all engines. I have sometimes adjusted the carb a little richer and helped some, but with that you are just robbing Peter to pay Paul. Some sugest the Gouernor spring is oscilating; I do see how that could cause it, but it is not the problem with all that does it. I believe it is the newer carbs. In 1997 the govt. mandated emmission control standards the manufacturers had to meet. This surging is a tradoff for cleaner emmissions. Some carbs on the market now are un-adjustable. It looks like we will just have to live with it.:mad:

[Robert Doubrava]

There you go. My grandfather's Toro push mower did that recently. I adjusted the carburator and it helped out a lot. Try that.

[vipermanz]

it's definetly a governer problem, i can push it one way and hold it there and it runs fine, push it another way and it trys to quit (butterfly closes), i don't think it has anything to do with the carb (it's a diaphragm style:( ) that draws straight from the tank:confused: :confused:

[sdwally]

Surging can be cause by a few different things.
1. Carb jet partially plug, not getting the right fuel mixture. Bad carb diaphragm and or pickup tubes(gas tank mounted to carb, no fuel line).
2. Governor out of of adjustment. On the governor arm at the end where the governor shaft goes into the engine, loosen the arm and push the arm to full throttle. Rotate the shaft in the same direction as to cause the arm to open the carb to full throttle. Retighten arm to shaft.
3. Loose carb or intake components and or bad gaskets. Sucking air to cause wrong air/fuel mixture.

Governor spring will not cause this problem, it will only affect top end speed of engine.

[Robert Doubrava]

Oh. I'm familiar with the old fashioned type carbs.How old is the engine? If it is not older than about 5 years, then that is pretty odd that that engine is doing that. It's a B&S Quattro, right?

[vipermanz]

you got, it 2-3 years old

[Remo Sid]

This problem is not caused by the governor adjustment. ( Do not) mess with the governor adjustment unless you are very competent in this area. You will end up with more problems than surging.

If you will think for a minute, the engines referred to here that have surging problems ( do not ) have an adjustable governor. The type engine you referr to with the adjustable ( mechanical ) gov. very seldom have surging problems, and when they do they respond well to making carb settings richer.

The last thing a novice wants to do is mess with the gov. setting.:angel:

[vipermanz]

i'll take it off tomorrow and see if anthing is up in the vane or around it maybe it got chipped:confused:

[Dave]

Give me the model&type,so I can see what ype of carb it uses,One thing you can try is to undue the thottle cable ,run the engine until warm,then hold the thotlle shaft at the carb at midrange,if it hunts then its the carb leaned out, if it doesn.t its the gov or linkage

[vipermanz]

here we go:

model 10a902
type 2291 b1
code 9910125

b&s quattro

if i hold the vane arm it runs normal

[Robert Doubrava]

Your engine was made in October 12, 1999, and assembled at manufacturing plant #5. Thats how to read the code on your engine. First two #'s : Year
Second two#'s : Month
Third two #'s : Day
Last two #'s : Assembly line and manufacturing plant.
That's some good info. I got from www.briggsandstratton.com There's a place on the website that'll even tell you what spark plug you should use in your engine. It says the reccommended plug you should be using is " RJ19LM or J19LM" It's the same one I'm using on my rider, push mower, and edger.

[Dave]

I looked at your motor the screen,If you hold the thottle shaft on the carb while its running ,as I stated before ,it should be the govener spring,I would start there,BS#690251 yellow spring,This is the procedure that briggs tells you do do if the engine is hunting,my gut felling is, if you have not played with the spring is that you have crap in the pickup tube of the carb.From what I have seen this is a plastic carb ,no adjustments ,made to run lean anyway.the carb list for about 20.00.bs498811,if you have the capilbility undu it off the tank and blow it out with air,do not try to clean it out with a wire as you will screw up the main jet let me know how you makeout,you metioned that you removed the flywheel cover and chk the vane???

[lawncare]

After u try the other remedies clean out gas tank and check carb it may have a little water in it you do this by taking off carb bowl and pour gas in clear jar if water n carb it will float to bottom if so rbuild carb and clean gas tank.

[Fish]

Your problem is not gov related, but air/fuel related.
Fish

[vipermanz]

i went along the whole carb and tightened screws on the carb itself, and it helped it Some, it still does it cut i will give it another go-over later.

[John DiMartino]

The carb is adjusted to lean,you have to richen it up slightly,I bet it gets better as it warms up,and it real bad when its cold,this will confirm the carb being lean.Do not touch the governor,it is just trying to keep the engien running a steady speed,but cant because the carb wont run in the midrange,so it gives it more,then less throttle to keep the rpms' up.

[vipermanz]

well, it runs fine for the first 20 seconds on a cold start, then it starts hunting worse and worse:confused:

there also seems to be no needle adjuster either:confused:

[Fish]

Stop by a mower shop and get diaphragm kit #495770 and go
through your carb and clean out the tank. While you have the
carb/tank off inspect the intake tube across the top for cracks
or looseness.
Fish

[vipermanz]

i just got finished rebuilding it now, there was the dirty stuff in the fuel bowl, cleaned it up to perfection and will try again tommorow:)

[Robert Doubrava]

Did you put a carb kit in it? That's what I need to put in my rider and my grandfather's edger. Post back with your results! Hope it worked well.:)

[vipermanz]

i didn't use a kit,(wrong term)?,but i think it was just clogged up in the first place,

Thanks for all you guys help, You led me to another successful end!:)

[Robert Doubrava]

A carb kit contains gaskets, springs, screws, etc. Just curious about it. Glad you got it fixed!!:) :) :)

[big james]

CAN YOU MOVE THE THROTTLE SHAFT BACK AND FOURTH IN THE CARB HOUSING ? IF THERE IS SLACK IN IT YOU WILL NEVER GET IT TO ADJUST RIGHT CAUSE AIR IS PULLED IN AT THIS POINT ,WHICH IS DOWNSTEAM OF WHERE FUEL AIR IS MIXED

[vipermanz]

it's fixed now , it was a gunked up carb, but thank you for the help:)