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Hello,
I am having an issue with an 11HP upright B&S engine on my generator.
It has always surged badly when running, I can add choke and it runs slightly better but still bad so I figured its a fuel issue.

I installed this new carb: https://www.amazon.com/dp/B099PQ7WYQ?ref_=cm_sw_r_cp_ud_dp_06FFVG3FCJ40V9R3NCY7
And this fuel pump rebuild kit: https://www.amazon.com/dp/B000A13FBU?ref_=cm_sw_r_cp_ud_dp_HTTBSA7BN27E06W70P3D

But still the same surging as before. Here is a video of the problem: https://www.dropbox.com/s/lt6ubhmewy6i0ck/IMG_1881.MOV?dl=0
Thanks for any help!
Joe-

get some WD40 in a trigger spray bottle, with the engine running, saturate the area around where the carb bolts to the engine. If the engine, runs better or blows white smoke, or has any change in RPM, you've found your vacuum leak causing a lean running condition.

Thanks! I'll give it a try!

JoeVB said:

It has always surged badly when running, I can add choke and it runs slightly better but still bad so I figured its a fuel issue.

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Fuel delivery issue, yes. Dirty carb, yes. Dirty fuel tank, probably.

Dirty cooling fins, most likely.

Scrubcadet10 said:

get some WD40 in a trigger spray bottle, with the engine running, saturate the area around where the carb bolts to the engine. If the engine, runs better or blows white smoke, or has any change in RPM, you've found your vacuum leak causing a lean running condition.

Click to expand...

No change at all when spraying the WD40. I was hoping that would be it. I am thinking about rigging up a temporary fuel source that will feed that carb via gravity to see if maybe the fuel pump is not pumping enough fuel.

slomo said:

Fuel delivery issue, yes. Dirty carb, yes. Dirty fuel tank, probably.

Dirty cooling fins, most likely.

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I haven't, I never thought about that, I will check.
The carb is brand new and the fuel pump was just rebuilt.

JoeVB said:

I am thinking about rigging up a temporary fuel source that will feed that carb via gravity to see if maybe the fuel pump is not pumping enough fuel.

Click to expand...

Now you are thinking.

New carb means nothing. Especially if it came from Amazon or Ebay. New carb needs to be tested.

JoeVB said:

I installed this new carb: https://www.amazon.com/dp/B099PQ7WYQ?ref_=cm_s

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Chinese carb alert!!

You need to ask Bertsmobile1 about his genius carb boiling method. I think this is the best way to clean these small carbs. I tried it once. Got kicked out of the kitchen by this barely 5 foot tall woman.

slomo said:

Now you are thinking.

New carb means nothing. Especially if it came from Amazon or Ebay. New carb needs to be tested.

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Good to know, thanks. It sure was inexpensive, should have been a clue.

slomo said:

Chinese carb alert!!

You need to ask Bertsmobile1 about his genius carb boiling method. I think this is the best way to clean these small carbs. I tried it once. Got kicked out of the kitchen by this barely 5 foot tall woman.

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Will do, thanks! Hopefully you've been re-admitted into your kitchen!

change the fuel filter if it has one.

I don't have a wife or girlfriend living w/ me to run me out of the kitchen!
I just gave a hot scalding bath to a small carb on a Craftsman Mini Tiller.
Wouldn't hit a lick and was being a problem child. I pulled the carb and
disassembled it completely, washed it and sprayed it off as much as I
could on the exterior. I took a styrofoam cup about 20oz and put a level
tablespoon of Baking Soda in it, added water about half way up the cup
and put it in the microwave to boil after stirring it up. After it boiled I put
the dis-assembled carb in it to soak several hours. I heated the water up
again after removing the carb and boiled the carb again and left it till the
next morning. Then rinsed it under the sink and took it outside and slung
what water I could out of it and laid it in the sun to dry. Then sprayed it
out with carb cleaner and used a fine wire (bread tie wire) with a 90* bend
in it to clean out the 3 venturi fuel orifices just behind the throttle plate. It
works for me every time. On a really tough, dirty carb I may have to boil it
out 2 or 3 times. Usually only once is sufficient.

JoeVB said:

Will do, thanks! Hopefully you've been re-admitted into your kitchen!

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You need two pots, the bigger the better
Firstly degrease the carb really well
Boil one pot and add a couple o dishwasher tablets into it
When fully dissolved drop the carb into the water & keep it on a rolling boil ( provides agitation ) for as long as you like but 1/2 hour is usually more than enough .
Bring the second pot to the boil and whip the carb out of the wash pot and into the rinse pot.
Boil hard for a couple of minutes
remove carb and blow dry if necessary but usually it will air dry in a couple of minutes .

bertsmobile1 said:

You need two pots, the bigger the better
Firstly degrease the carb really well
Boil one pot and add a couple o dishwasher tablets into it
When fully dissolved drop the carb into the water & keep it on a rolling boil ( provides agitation ) for as long as you like but 1/2 hour is usually more than enough .
Bring the second pot to the boil and whip the carb out of the wash pot and into the rinse pot.
Boil hard for a couple of minutes
remove carb and blow dry if necessary but usually it will air dry in a couple of minutes .

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LOL No wonder you got ran out of the kitchen! I call it 'Making Carburetor Soup'. I'll try your method and see
how it works. Thanks.

Two things I’ve found when working on engines mounted to generators. 1. If it has an auto idle system, engine idles when no load applied, this system is not working properly. It can’t detect load no load. 2. The governed top speed is not set properly. On generators, the governor controls not only engine speed, but this controls voltage, current and hertz output. If a good carb is installed, this is the first thing I check, because being off will cause surging and burn out equipment when customers set the governed top speed too high to reduce surging.

Slomo was lucky he only got kick out. My mother would have used an iron skillet on me.

To OP while the engine is running try holding the thottle assembly steady. If the surging goes away and engine runs smooth then the governor is out adjustment. If the engine accels or dies then it is the carburetor that is the problem. Many China carbs are just junk. I got lucky on the last Chinese Nikki clone that it just need the jets resized.

Rivets said:

Two things I’ve found when working on engines mounted to generators. 1. If it has an auto idle system, engine idles when no load applied, this system is not working properly. It can’t detect load no load. 2. The governed top speed is not set properly. On generators, the governor controls not only engine speed, but this controls voltage, current and hertz output. If a good carb is installed, this is the first thing I check, because being off will cause surging and burn out equipment when customers set the governed top speed too high to reduce surging.

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Good information.. Thanks!

StarTech said:

Slomo was lucky he only got kick out. My mother would have used an iron skillet on me.

To OP while the engine is running try holding the thottle assembly steady. If the surging goes away and engine runs smooth then the governor is out adjustment. If the engine accels or dies then it is the carburetor that is the problem. Many China carbs are just junk. I got lucky on the last Chinese Nikki clone that it just need the jets resized.

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Thanks, I will try that.

I've got a 5500w Troybuilt generator with a Briggs engine. It would surge from the time I bought it new until a couple years ago and decided I would look at the governor. Mine had a spring with different holes to hook it in. I switched holes and it smoothed right out.

As far as cleaning carburetors, I've never tried this, but on a go-kart forum I follow, those guys recommend boiling them in lemon juice. They swear by it.

catman606 said:

I've got a 5500w Troybuilt generator with a Briggs engine. It would surge from the time I bought it new until a couple years ago and decided I would look at the governor. Mine had a spring with different holes to hook it in. I switched holes and it smoothed right out.

As far as cleaning carburetors, I've never tried this, but on a go-kart forum I follow, those guys recommend boiling them in lemon juice. They swear by it.

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Lemon juice , vinegar , both mild acids that will clean zinc & aluminium
Boiling expands the passages so stuck in crud can got back out & the mechanical action of bouncing around in the pot aids this.
I used to do the same thing with dishwasher tablets which actually works better than an acid wash as alkalis break down fats better than acids do .
Now I have an ultrasonic cleaner which does the same job a lot lot quicker with a less corrosive solution.