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Inveterate Putterer
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Discussion Starter #1
You can listen to this vid to get a sense of what the symptoms are. When it runs, a little choke makes it run better, but not perfect. That said, I can mow with it just fine.

I have zero experience with this engine. It is a Briggs Vanguard 16 HP V-twin.

 

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Do you have a air adjustment on this carb? Sounds like it's running a little lean, the choke making it run better is a clue to that. A little less air may help it. If you do not have any adjustments, your only hope is to clean the carb out the best you can like the other poster said. If you get it running good, stay away from that ethanol fuel. Hunt high and low, more than likely someone near you sells non-ethanol fuel.
 

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Definitely a carb rebuild is in order.....you may get away with removing the carb and ultrasonicaly cleaning it and trying to use very small drill bits or wire to clean out all the passages I am pretty sure that the carb has been superseded and although the replacements available are expensive, not really an exact fit..there is a guy in Maryland that I dealt with a few years ago that was living in Maryland at the time...he may have moved, but I had gotten his contact info by calling B&S ..this guy can rebuild these older carbs very inexpensively ...PM me if you want his contact info
 

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Inveterate Putterer
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Discussion Starter #5
Franklin2, that's kinda where I got flummoxed. There are two adjustments. one is a simple idle screw that acts on the throttle linkage. The other located very near the bottom of the carb so I'm guessing a high speed adjustment. Turning it has no discernable impact.

This tractor ran well when i got it about a year ago. So logic would seem to suggest crud in the carb.
 

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Inveterate Putterer
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Discussion Starter #6

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Definitely some crud in the carb. The surging is the governor functioning properly and trying to compensate for the lack of the proper amount of fuel going to the engine. Those carbs are very similar to carbs used on later model Onan's in that you can clean them in place by just removing the air cleaner and top of the carb. If you do a full cleaning than you have to remove the intake manifold and then remove the carb from that. I would do an in place cleaning first and see where it gets you, particularly since it's already been run regularly and it's not like it's been sitting for a long time with bad fuel. I've always had good luck with that method.

Rick
 

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Franklin2, that's kinda where I got flummoxed. There are two adjustments. one is a simple idle screw that acts on the throttle linkage. The other located very near the bottom of the carb so I'm guessing a high speed adjustment. Turning it has no discernable impact.

This tractor ran well when i got it about a year ago. So logic would seem to suggest crud in the carb.
Like I said I don't know your carb. But most of the older ones had another adjustment screw higher up on the carb somewhere. It was for idle air.

The one screw you mentioned already is the idle stop screw, which sets the idle speed. The other screw sticking out low is the main jet adjustment screw. This main jet adjustment is made by putting a load on the engine, preferably a mower or something that presents a load on the engine, rev the engine up high and put the load on it. Then adjust this screw in and out till it runs the best.

Look around for another mysterious screw up higher on the carb somewhere. It will usually have a spring behind it to keep it stationary after it's adjusted.
 

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If none of the cleaning works, make sure you closely inspect for any hairline cracks or fractures in the carburetor body and mounting flanges. Also check for a warped flange on both the carb body and the intake base. Either could cause a vacuum leak which could cause the tractor to run better/worse as it warms up and moves around the yard.

Dad still liking the 16G you sold us, too. :fing32:
 

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Inveterate Putterer
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Discussion Starter #10
If none of the cleaning works, make sure you closely inspect for any hairline cracks or fractures in the carburetor body and mounting flanges. Also check for a warped flange on both the carb body and the intake base. Either could cause a vacuum leak which could cause the tractor to run better/worse as it warms up and moves around the yard.

Dad still liking the 16G you sold us, too. :fing32:
Hey, how are you! Glad the 16G is still working for you.

I had planned to get into the carb this weekend but now it wall have to be next week. Do these particular carbs have a problem with cracks in the body? I've worked on a lot of Kohler carbs but this is my first Briggs Vanguard.
 
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