Like New Engine Surging / Hunting: Can I Set Choke Higher and Be OK?

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  #1  
Old 10-12-14, 03:38 PM
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Like New Engine Surging / Hunting: Can I Set Choke Higher and Be OK?

Hi Everyone,

I have a like new (2010) Troy Bilt Generator that is surging or hunting where:

* Model # 204412 Briggs and Stratton engine
* Ran flawlessly for 3-4 years when used (very little)
* Only has 26 hours on it (kept records)
* Treated with stabilizer each year
* Sat for 2 years at one point
* The air filter is like new when I checked
* I turned the small screw near the carb both ways, it made no difference

When I move the choke lever towards the "Choke" label almost all the way, it smoothes out nicely. If I run it like this permanently, is it running the way it should and I'm OK, or could I be doing long term damage to it or using a ton of extra gas?

Thanks in advance. -Tony

P.S. Briggs and Stratton website says it can be set like that for the first few tanks of gas since the pollution controls are so demanding. But mine never did that ...and now is, so I feel like it's not the same cause.
http://www.briggsandstratton.com/us/...ng-and-surging
 

Last edited by tony17112acst; 10-12-14 at 05:26 PM.
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  #2  
Old 10-12-14, 03:51 PM
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A normal choke plate puts a restriction in the carb throat, so a lot of your top end would be lost. The fuel that goes through the choke circuit isn't going to be metered very precisely either so getting a predictable mixture would be difficult.

I don't know about the B & S manual reference to doing that for break in. Some of the other guys here may.

The best thing to do, IHMO, would be to clean the carb. I would try Sea Foam first, to make it easy if that gets the job done.

If there are still problems after that, it'll have to be taken off, disassembled and cleaned.
 
  #3  
Old 10-12-14, 05:54 PM
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That info on the B & S site isn't referring to what you have there. The air flow through an engine and carburetor will stabilize as the parts break in to seal the combustion chamber/gases of the engine. During break in there will be additional blowby on the rings and back wash from the combustion chamber into the carburetor throat past the intake valves.

Once that air flow stabilizes it becomes a predictable part of the equation in the design of the air fuel mixture at different rpms. From that engineers can determine and control emissions. With a slight choke setting you can override the variables of the parts that haven't broken in.
 
  #4  
Old 10-12-14, 07:15 PM
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Put a strong dose of SeaFoam or Chevron Techron in the tank and it will take care of itself. Have a good one. Geo
 
  #5  
Old 10-13-14, 05:29 AM
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What does SeaFoam do? ...and how did my engine develop this so I may avoid it next time?

Thanks again!
 
  #6  
Old 10-13-14, 05:55 AM
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You said it sat for two years at one point and has had very little use so I suspect that it's a simple problem of bad fuel. Fuel preservative helps prevent varnish from developing in fuel but it's not magic. I think you just need to disassemble and clean the carburetor. Empty the fuel tank and drain the fuel line and fill with fresh gas.

Sea Foam can help dissolve and break down the varnish deposits left by the old fuel. It does not always work especially if the jets in the carburetor are completely blocked but it can work in areas where fuel can still flow. It's cheap and easy so it's worth a try before pulling the carburetor.

In the future, before long term storage, you'll have to drain all the fuel from the machine. Then try to start and run the engine and nurse the chose to keep it running as long as possible to get any remaining fuel out of the carburetor.
 
  #7  
Old 10-13-14, 05:59 AM
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Sea Foam dissolves varnish from the natural separation of gasoline. Todays fuels are worse than those of twenty years ago and separate more quickly.

When you use the engine weekly you wouldn't need an additive, but when it sits for a month or longer, you can add Sea Foam to clean it up and Stabil to keep the fuel from breaking down.
 
  #8  
Old 10-13-14, 10:33 AM
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There was no gas in it when I put fresh gas in to start it up (to change the oil).

Also, when I try the SeaFoam, should I run it with the engine with it surging, or run it smoothly with the choke almost fully on? Thank you.
 
  #9  
Old 10-13-14, 11:20 AM
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Run it with the engine surging so you can hear the change as the SeaFoam works, drain the current gas and put in a mixture of about a pint of gas and 2oz of SeaFoam, start the engine and let it run for about 10 minutes, shut it off and let it set for 30 min then start it and let it run dry, problem should be solved. Have a good one. Geo
 
  #10  
Old 10-13-14, 01:09 PM
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OK, I tried the SeaFoam treatment as recommended above and it did NOT work. The generator came with a fuel line cut off, so I was able to stop the gas from flowing in instead of needing to wait till the tank was empty, but I did let it sit with SeaFoam in it for 30 minutes and then ran it for another 30).

Question #1: I don't know anything about carburetors, so do I just learn, take it apart, and then clean it at this point?

Question #2: Since the generator comes with a gas line cut off - is cutting it off and letting it run out of gas an effective way to storing it long term (1+ years). I'm under the impression that letting gas (mine was treated with Stabil) in the carb is what gave me my problem.

Thanks to everyone!
 

Last edited by tony17112acst; 10-13-14 at 01:38 PM.
  #11  
Old 10-14-14, 04:30 PM
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For what you have in the carburetor, the Sea Foam treatment would be first choice and effective most of the time. There's always a possibility of an obstruction elsewhere, but since you get it to run fine with the choke, that says the problem is in the carb. It having sit for an extended period would say it's a varnish problem and not a solid like trash or dirt. The latter is seldom the problem when the filter is in place.

I would try the Sea Foam again. I usually put 4 ounces in a quart of gas. Then, if the engine will start, let it run on the doctored up gasoline for about ten minutes, let it sit for ten, then repeat. It will draw the SeaFoam into the carb and will work to clean everything. Repeating will work to flush it out.

This about the same thing Geo has told you. I would keep doing it until it cleans up.

I normally would tear it down as a "have to" although a lot of techs here go straight to tearing it down. My philosophy is take the easy way out.

As far as leaving the generator sit for a long period of time, you should run the carb dry and drain the fuel from tank. then when you start it the next time, add a little Sea Foam or a cleaner to the first tank to take out residue.
 
  #12  
Old 10-14-14, 09:23 PM
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I would just open the carb and clean it. Seafoam at 10 bucks a can and your time whatever it's worth... not to mention seafoam can't remove trash like corrosion and dirt... it's just not the correct way to solve the problem. Sometimes it works, sometimes it doesn't. If there is rust and water in the carb, you need it out now before it creates more damage and ruins the carb. A $4 can of carb cleaner and 30 minutes is probably all you need.
 
  #13  
Old 10-15-14, 06:29 AM
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I looked up how carbs work and I'll carefully take it apart and see if there's anything in there. I can't imagine there is since it's stays inside full time and is basically like new, but it IS 4 years old. I'll report back in 2 days; I can't move my neck today.
 
  #14  
Old 10-15-14, 07:47 AM
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Here are some instructions for you. Verify that this is your carb first.

Disassembly, Cleaning and Repair of Briggs and Stratton Intek Single Cylinder OHV Nikki Carb
 
  #15  
Old 10-15-14, 09:37 AM
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I usually do not bother with Sea Foam though if you've got it already you have nothing to loose. I find it quicker and more reliable to disassemble and clean the carburetor. Before you start take detailed photos of how the carburetor linkages (governor, throttle and choke) are connected so you can put it back together correctly.
 
  #16  
Old 10-15-14, 10:12 AM
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Even though it is kept indoors, it can get water either from the gas can, or through condensation that occurs with temperature changes.

I do believe in seafoam, but mostly for prevention or to smooth out slight rough performance fromt he carb. I use it in my motorcycle sometimes when I get a mid-range stumble and it clears it right up. It's good stuff, but there is still no such thing as a mechanic in a can.
 
  #17  
Old 10-15-14, 05:34 PM
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UPDATE

Wow, thanks for that link!! That *IS* my carburetor, but there's no throttle to it (being a generator).

OK, I have removed the bowl from the bottom, and left the carburetor attached to the engine and I:

(1) Cleaned the inside of the bowl completely (to perfection) with a small brass brush;
(2) Made sure the float had no gas in it and inspected the inlet needle;
(3) Made sure all of the holes in the rod (emulsion tube?) were clean with a small wire.

However, it still surges or hunts. What else can I do? I don't know what the long rod is for that seems to control the throttle ...but what is telling the arm to pull/push? The link is awesome, but it doesn't tell me what to clean; it just describes everything.

Here are some photos:


Larger Image = http://www.tonytonini.com/carb1.jpg
This is what it looked like when I pulled it ...it's all clean now.


Larger Image = http://www.tonytonini.com/carb2.jpg
I made sure all of the small holes were clear and clean. I didn't remove the carb, so there may be some I couldn't get to.



Larger Image = http://www.tonytonini.com/carb3.jpg

Should I have sprayed everything with carb cleaner? I'm not sure what else to do, but I do have the time to do it.

-Tony
 

Last edited by tony17112acst; 10-15-14 at 07:32 PM.
  #18  
Old 10-16-14, 01:50 PM
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OK, this time I removed the carburetor completely and used carb cleaner on it and it looks to be running fine. I sprayed in every little hole I could find even though I didn't know if it was used or not. Removing the carb on this generator was a breeze ...5 minutes tops.

Thanks SOOOO much to everyone for all the advice. A cheap can of cleaner is all I needed! (versus taking it to a small engine shop)

One last question: How do I prevent this again? I used Stabil in my gas correctly (and followed the directions) and it still got gummed up. I have a built in gas shut off valve; if I put Stabil in, let it run for 10+ minutes, and then cut off the gas supply ...is that what will stop this in the future?
 
  #19  
Old 10-16-14, 08:07 PM
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Even running it dry, there will be a small amount of gas left in the carb that will dry up and/or turn to gum or varnish. Carburetors used to have bowl drains on them to allow complete drainage of the bowl, but not these days. If it is something that you will use a few times a year, then crank it up once a month and let it run 10 minutes or so and that should help keep it from gumming up again. The smaller the amount of gas, the faster it goes bad. That in the carb will go bad much faster than what is in the tank. Let it run and burn it off and get fresh from the tank. If you aren't likely to remember to crank it up this often or don't want the hassle, the best thing to do is shut off the gas and drain the bowl. Keep stabil in the gas tank to keep that gas from going bad so quickly too.
 
  #20  
Old 10-17-14, 07:00 AM
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Thanks a lot Cheese!

This generator will easily sit for 1-2 years at a time since the only time we run it is when we lose electricity for more than 8 hours. So I will remove the carb bowl and discard the gas after cutting the gas off with the cut-off switch and letting it run down ...unless someone here points out that that'll be insufficient.
 
  #21  
Old 10-17-14, 08:38 AM
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If it will sit that long, I'd suggest draining the tank too. Just run it in your car or lawnmower rather than have it separate in the tank. That can be a mess to clean up when gas separates in a tank. It drops a sticky syrup on the bottom of the tank that slowly makes it's way to the carb.
 
  #22  
Old 10-17-14, 02:04 PM
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OK, sounds good. I just ran the tank dry as I had only a pint in there. I'll open the bowl and let things evaporate.

Thanks again for helping me out. I have learned so much and will pass everything on to my family/friends on how easy it is to clean/maintain a carburetor! I have a power washer, snow blower, generator, push mower and a lawn tractor, so I'm set for life!
 
  #23  
Old 10-17-14, 06:29 PM
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I have a large amount of equipment and properly winterizing is a chore. Then, being in the south there always is the warm spell that has me get something out in the middle of winter. Aviation gas (AVGAS, 100LL) works well. It's more expensive as auto gas but it's much more highly refined and contains no alcohol. It has a very long shelf life and I have never seen it develop varnish or other nasties. At the end of the season I switch over and run my small engines on 100LL and don't worry about the fuel.
 
  #24  
Old 10-18-14, 08:25 PM
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What I did to my generator was I put a tri-fuel kit on it, which lets me run on propane or natural gas, in addition to gasoline. You can drain all the gasoline out, and if you only ever use it for backup, keep a cylinder or two handy and you'll never be in the dark.
 
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