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rich_kildow

*UPDATE/FIXED* 7116 gas flow problems

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rich_kildow

I've been chasing this problem around for the last 2 years or so but my 7116 is still getting to much gas. In the past, she'll run ok for a while but shortly foul out the plug (dark and full of gas) and require it to be brushed off. Lather, rinse repeat. I've always had problems with it leaking gas while sitting, even after overhauling the carb, so I installed a fuel shutoff.

Today I started it up for leaf duty and it would idle good for 5 seconds, then bog for a few seconds, over and over. I pulled the air cleaner and watched down the intake while it did this and fuel is constantly flowing out of the large tube (not the emulsion tube) in the intake area. I've suspected that the bowl was to high and therefore not shutting of fuel, so I pulled it apart and checked that the bowl was sitting on the needle spring wire horizontally, which it was. I figured that if I set the bowl to lower the fuel level, that is angled instead of horizontal to apply more pressure sooner, it would let me know if the fuel level is wrong. Reassemble, and it still flows fuel like mad.

It will run good for a minute if I close the shutoff and it starts to pull that extra fuel out of the carb body. I can keep it going nicely by feather the fuel shutoff to give little bursts of fuel. I'm at a loss with this carburetor and am about ready to throw in the towel...how do I fix this?

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rich_kildow

Please let this be the problem:

Is the float spring supposed to be under the tab on the float, as in the last picture on this page?

http://outdoorpowerinfo.com/repairs/briggs_small_two-piece_flo-jet.asp

If so, this might explain my problems as the tab would have been pressing on the spring, not the end of the needle valve, and therefore not applying as much pressure.

I also stumbled across this is anybody else needs help:

http://www.smallenginerepairs.info/briggs-stratton/briggs-stratton-carburetor-two-piece-flo-jet-service.html

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BLT

Does your float valve have a viton (rubber is shown in instruction sheet) tip or is it a solid metal tip? If it has the all metal tip, is the seat for the valve installed and correctly?

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Tarheel

Years ago, when the trouble with alcohol in fuel first started to become a problem, a rep for one of the engine companies ( Paul berthrong (spelling) from AEA maybe? To many years to recall for sure )

Anyway, he took a plastic gas container and filled it with 10% ethanol fuel. Let it set maybe half an hour and then poured it through a paint filter.

Tapped the filter on a dark piece of paper and there was something that looked like cat hair all over the paper. This, he told us, was plastic that was broken down by the alcohol in the fuel.

This "hair" was so thin that I could not see it unless it was on the dark background but it was enough to hold a needle and seat open.

Big problem for tractors and machines with plastic fuel tanks like the RBTs of that time. A GOOD fuel filter (not a screen) and replacement fuel lines (I use Tygon w/o problems) along with blowing out the carb once more seems to cure this.

There is also a chance that the main jet is leaking. Make sure it is seated tightly.

Good luck with it.

BTW, there are places selling pure gasoline w/o alcohol in it. I am told Stay bill sells a treatment for alcohol as well but I have not used this and can't say.

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Brettw

Could you float have hole in it? Make sure it isn't full of fuel. Other wise, very carefully, adjust the tab on the float just a bit and see if that will seat the valve. Sort of like the float in a toilet tank, sometimes ya gotta "adjust it by bending the rod.

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Multiplicity

.

...I had a weird situation on one carb, where

"The Long Tube" screwed up into the throat of the

carb - beside the hole to the idle circuit it should

be into, that would allow bad idle and leakage too.....

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Burntime
quote:Originally posted by Brettw

Could you float have hole in it? Make sure it isn't full of fuel. Other wise, very carefully, adjust the tab on the float just a bit and see if that will seat the valve. Sort of like the float in a toilet tank, sometimes ya gotta "adjust it by bending the rod.


id="quote">
id="quote">Brett, is that the "big hammer" theory?:D

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rich_kildow

Updates, and weird ones at that.

First, I've checked everything at least 5 times now:

- Rubber needle valve is new and seals well, checked with compressed air. I had the float tab resting on the spring/clip, not on the head of the needle valve.

- Emulsion tube is seated firmly but not overtight and is in its hole in the updraft area of the carb.

- Float is good. No sloshing and held it under water just to be sure and no bubbles. Float is set to be horizontal with the body of the carb.

- Non-ethanol fuel for the year and a half I've been the owner and new lines, filter, and carb rebuild since then. No screen in the bottom of the tank at this point, but again it has a good inline filter that gets changed regularly.

Anywho, she runs great now...at full choke. I made sure the choke cable hadn't somehow gotten reversed at some point or run through the wrong point or ANYTHING, but no, she purrs at full choke and dies with it off. The direction the arm on the carb has to move for choke is indicated in the body, so I know that's right. I've tried taking the choke off slightly and fiddling with the mixture in case it happened to be that far off, but can't get it. Main jet it 2 turns out and idle is 1.5 turn out, by the way.

What's even more puzzling is she only starts (at full choke) if I read forward and give the throttle shaft a twist all the way forward, then it takes right off. You can crank the battery dead and if you don't touch the throttle on the carb, it won't take. Idles great, revs up and down fine, but all at full choke and only if I fiddle with the throttle.

At this point, I wish I had $1300 laying around to just be done with this motor and put the repower kit in it.

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rich_kildow

I'm going to go beat my head against the wall some more...why didn't I think of that?! I wonder if I didn't damage the gasket from carb to manifold. The manifold elbow never came off the motor through all this so I'm sure its fine. Anything wrong with RTV to make a gasket from the carb to manifold since I don't have any gaskets on hand?

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fishnwiz
quote:Originally posted by Ronald Hribar

You must have an air leak either at manifold and carburater or manifold and motor


id="quote">
id="quote">I agree with Ron....Air leak. Best of luck on tracking your issues!

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Rebmo

I had a dirt bike with those symptoms. The primary fuel circuit (in the carb) had a fine metal sliver in it. You said you used compressed air; but did you blow it through the idle and main fuel circuits with jets (if it has jets) removed to make sure the flow is unobstructed. You should feel a good volume of air coming out the venturi openings. If the tiny idle circuit passage is plugged it may idle poorly using the main fuel circuit which poorly meters fuel(active when choked)for idle. As the engine warms it will be running super rich at idle and foul the plug. My dirt bike would die at idle once it warmed up since the idle setting was set extremely high to close the blade enough to create enough vacuum to pull fuel from the main fuel circuit (same as what choke does).

The Suzuki DT250 dirt bike was an 82 and never really used since it had this issue likely when new. Techs rebuilt the carb multiple times. I bought it cheap and found this issue. It looked like when installing the idle circuit jet the installer got ambitious with the install tool and a shaving got loose and lodged in the idle circuit only to be discovered over 20 years later.

I would recommend being absolutely certain the idle circuit is clear using compressed air. Just a thought............... Good Luck!

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rich_kildow

I think things may finally be sorted out with this tractor. The list of problems I've been chasing around are:

- Float installed wrong on the needle valve. The clip wasn't between the tab and body of the float.

- Bad carb to elbow gasket

- WOT RPM was set to just under 3000

This had me chasing around fouled plugs, poor performance, constantly leaking carburetor, and I was never quite able to tune the carb. I'm looking forward to using this the way it was intended and hopefully I finally have it figured out.

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