Carburetor help needed on an old Briggs

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  #1  
Old 10-07-08, 12:01 PM
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Carburetor help needed on an old Briggs

I have an old B&S 8HP generator. I wore it out during hurricane IKE. I rebuilt the carb, but am having some issues with adjusting the carb and getting the carb body gasket to seal. Here's the particulars: Model #190432 Type 5163-01 Code 90071810
It has the "pipe-type" air cleaner. At the advice of a local shop, I bought carb kit #394693. After I did the rebuild, I used the parts look up to troubleshoot and found that it should have been kit #398235 (used after code date 84100700). Anyway, it seemed to run O.K., at first, using the parts he sold me. All the parts matched up except for a couple that didn't belong to this carb and it seemed as if I had everthing I needed in the kit. After it ran for a few minutes, it started losing power and I notived a little gas leaking from the body gasket...here's my problems/questions:
1) The carb body gasket is not sealing well...I checked the parts look up and found that the gasket in the kit I bought is the gasket that's supposed to be used for this carb (PN#27918)...in fact, it's the same one I pulled off when rebuilding. It leaks gas from the gasket just below the idle mixture valve (PN#292681). Upon further inspection, it looks as if the two surfaces of the upper and lower carb body do not mate up flat. The upper body seems to be bent downward where the assembly screws go and its creating a gap just below the idle mixture valve...What happened??...Any solution other than buying a new upper body assembly?
2) I don't know how to properly adjust the valve needle that goes into the carb nozzle on the bottom of the carb. I also don't know how to adjust the idle mixture valve on the upper part of the carb. Everything about this subject that I've found online so far assumes that there is throttle on this thing...no throttle, just on or off.

Sorry for the lengthy post...this thing is kickin' my @%&# and I need a little help....Thanks in advance

Shane
 
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  #2  
Old 10-07-08, 02:11 PM
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Did you assemble the top and bottom together before or after you installed the nozzle?

If you installed the nozzle first, it could keep the top from fitting correctly to the bottom.
 
  #3  
Old 10-07-08, 09:26 PM
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Yes, I assembled the top and bottom together first. Then I installed the nozzle and the two valves. I noticed when taking it apart that the nozzle had to be remove first, so I figured the reverse was true for installing it. Aren't these carb bodies cast?...I just can't see the thing bending without breaking.
I looked at the parts look up again and found a picture of the gaskets that come with the kit for the carb I have (for after code date 84100700). If the picture is accurate, it shows two identical gaskets. The one I bought had two different gaskets (one obviously for another carb that this kit will work for). I've never heard of this before, but is it possible that this carb requires two gaskets stacked on top of one another and that's the difference between the two carb kits?
 
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Old 10-08-08, 01:22 AM
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The gas should never get high enough in the bowl to even contact that gasket. The fact that it is tells me the needle isn't seating properly. This could be due to a sticking or bad float, dirty seat, etc...
 

Last edited by cheese; 10-09-08 at 12:06 AM.
  #5  
Old 10-08-08, 08:25 AM
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Originally Posted by cheese View Post
The gas should never get high enough in the bowl to even contact that gasket. The fact that it is tells me the needle isn't seating properly. This could be due to a sticking or bad float, dirty seat, sticking float, etc...
Interesting...I pretty sure this carb has been rebuilt before...I'm wondering if the original needle was the aluminum one that requires a viton seat to be installed and whoever rebuilt it put the viton needle in it that doesn't use the seat...I rebuilt it using the same parts that I took out of it (which had the viton needle and no seat).

Is the orientation of the needle hanger critical?...I didn't pay attention to that when disassembling.

Would the motor run with too much gas in the bowl?...because it does run...it just leaks a little gas from the gasket.

I apologize if my terminology is incorrect and questions are off the mark...I'm no mechanic...I just like to tinker.
 
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Old 10-08-08, 10:39 AM
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Does it continue to leak gas while it sits not running?

Yes the position of the little hanger on the float can make a difference.

Even if the carburetor is not flooding, the two halves need to be sealed to prevent dirt from getting into the carburetor and fuel from leaking out while running.
 
  #7  
Old 10-08-08, 02:21 PM
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Does it continue to leak gas while it sits not running?
It's hard to say for sure, but it does still have some gas on the side of the bowl...I figured that would have evaporated by now. I guess the answer is yes, but I'll wipe it down and check it tonight.

Any rule of thumb on which way the hanger is supposed to be oriented?

Even if the carburetor is not flooding, the two halves need to be sealed to prevent dirt from getting into the carburetor and fuel from leaking out while running.
Can I use a couple of stacked gaskets instead of just one to seal it up?
 
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Old 10-08-08, 06:25 PM
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With the carburetor inverted and the float and needle and seat installed the float should sit fairly level with the carburetor body.

I guess stacking the gaskets may be worth a try, but I am unsure if this will affect the operation of the carburetor any, as far as the high and low speed delivery of fuel through the carburetor is concerned.
 
  #9  
Old 10-08-08, 08:22 PM
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I just checked the carb after I wiped it down a few hours ago and it doesn't appear to have any leakage.

the float should sit fairly level with the carburetor body
I checked that prior to assembly and it was very level, so I guess I got it right...everybody gets lucky sometime.

I'll tear it down again as soon as I get a chance and start from scratch. If I can figure out how, I'll post a picture of the lower and upper carb bodies cleaned up and mated together so y'all can see the gaps I'm talking about. Someone may take a look at it and tell me to junk it before I waste another kit on it...or have another solution.

I guess stacking the gaskets may be worth a try, but I am unsure if this will affect the operation of the carburetor any, as far as the high and low speed delivery of fuel through the carburetor is concerned.
Do you not think that's there's enough room on the thread of the high/low needle to make up the difference?
 
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Old 10-09-08, 12:09 AM
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Ok, I had the impression it was leaking from that gasket all the time. It's just when it's running? If so, then it's not the needle. I think I'd use a straight edge and a file to obtain a flat surface for the gasket to seal against, but the stacked gaskets may do the trick. I never tried it.
 
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Old 10-14-08, 09:53 PM
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Thanks for the help so far folks. I had a little time to tear this carb off again and break it down.

Cheese....after it sat out in the garage a few days, it did appear to have a very small leak. I found more gas on the lower part of the carb before I took it off tonight.

Here's a few pictures...
You can clearly see the gap here (held upside down):

You can see the gap is more pronounced on the right side of the carb here. (This is where the leak is occurring)

You can see how the flanges where the through-holes are for the assembly bolts seem bent upward (downward when assembled)


Any ideas how this could happen? Did I do something wrong during assembly? Can the flanges be bent, or should I just start filing away?
 

Last edited by CaptNasty; 10-14-08 at 09:54 PM. Reason: picture change
  #12  
Old 10-14-08, 11:04 PM
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ouch...that doesn't look right at all. I'd guess that something is bottoming out that shouldn't be. I don't know if I have one of those carbs to look at in the shop or not. Take a close look at the 2 parts and see if you can see what is hitting and keeping the two halves from going together. If there was just a little gas wetness on the bottom part of the carb, I don't think I'd worry much about the needle seating. With a gap like that, I would expect some fuel seepage over the edge. Now if it's dripping, that's another story. Still, you need to fix the gap. Something is more than just "warped" here. Something is interfering with assembly.
 
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Old 10-15-08, 06:25 AM
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Something is more than just "warped" here. Something is interfering with assembly.
That's exactly what I thought too, but there's nothing in the way...I've checked repededly. Here's a little history on the generator: I got it from my next door neighbor who decided to go to his country home that had power when the power went out here during hurricane Ike. When he got back, he had a new generator with him that was powerful enough to run his pool pump and a few other things...must be nice.
He said that he had the generator "serviced" last year to the tune of about $150 and that "he didn't want it back in his garage". I don't know what was done, but the carb could have been rebuilt during that time...it could have happened then. The whole time I used the thing...it leaked a little gas. I didn't notice it until the 2nd or 3rd day, so it was like this before I cracked into it. It was not as extreme as it was after I did my rebuild, but I'm guessing that's because of the new gasket.
Upper carb body part #399443: $47.75...ouch (this is why I'm asking about how to repair).
Assuming nothing is in the way of assembly (nothing is), how would you approach correcting the bends?
 
  #14  
Old 10-16-08, 07:52 PM
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I packed up the disassembled carb and took it to a small engine repair place to get some more ideas and the owner took one look at it and asked if it was leaking. He said that he's seen tons of these carb and that they all have leaks after a rebuild. The flanges with the holes for the assembly bolts are always the culprit. He said they've tried double stacking gaskets, #2 Loctite, and filing the surfaces...nothing works. He said filing the surfaces made it worse. I looked at it pretty good with the idea of filing it down, but decided that the best way is to file the lower assembly to accommodate the bends in the flanges. If it doesn't work...I've ruined a lower assembly.

I will bite the bullet and buy an upper assembly from Briggs and go from there...exactly what I was trying to avoid.

Thanks for the input...I'll probably jump back in this thread when I get the part, assemble the carb, and try and tune it.
 
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Old 10-16-08, 08:44 PM
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If you're set to buy a new top part anyway, go ahead and see if you can bend the flange straight again... if it breaks, you were gonna buy a new one anyway. I've worked on a lot of these and don't ever recall seeing one bent like that.

Thinking about it... how can simply rebuilding the carb cause the flange to bend? (unless they have a gorilla rebuilding carbs for them). I don't buy what the guy told you because I've worked on many of that style carb without problems like that. I don't think filing is the answer for yours either. Your flanges are too bent for that. I'd try to straighten it or replace.
 
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Old 01-04-09, 06:54 AM
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Smile Please post results

Hello Capt, I would really like to know if you got the carb/engine running correctly. These carbs can be a nightmare, if your not familiar with them. It seems that any, and everything that could go wrong did go wrong.
I have the same carb on my "VOLT".. 4400 watt Generator of 20 years ago. Please, update us as to what were the remaining things you did to get it running. Thanks, Nitrojc.
 
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