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rfsmith1952

Briggs Carb

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rfsmith1952

Well, I rebuilt the carb on the T-12, and the results were not so good. It leaks at the bottom pretty good, and only starts/runs with the choke control all the way out. I cleaned everything up pretty well, installed the rebuild kit parts, and made some gaskets for where the pipe from the carb meets the engine. I installed new governor springs. I set the carburetor adjustment screws out one and a half turns, and have been trying to get it running right, but no progress. On the other hand, it was the first time I did a carburetor, I learned a lot, and it sort of works! 8D Any guidance would be appreciated!

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fishnwiz

There is a post on leaky Briggs carb in the tips section that may be of help. There are also several vids on YouTube that you may want to view. Just type in carb float adjustment on briggs carb and you will get several informal vids.

You may need to re adjust the float angle in the carb to a slightly lower position in the carb so the fuel bowl does not over fill with gas. Was the needle valve that you removed from inside the carb body attached to the float, the same is the one you had in your rebuild kit? There are two different kinds that sometimes come with the kit. One has a brass tip and one has a rubber tip on the needle...you do not want to mix these up. If orig needle was rubber tip...you need to replace with the same type needle. Rest assured that I am by no means anywhere near an expert on carbs , but I have rebuilt 50+ over the years, and some of mine still leaked after the rebuild so do not get discouraged. Sometimes you may need to go back into the carb for a little fine tuning.

Congrats on making the effort...each time you try, you are sure to learn something new!

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JimH

Bob,one of the causes of leaky Briggs carb after proper float adj and new needle and seat, is fuel seepage where the emulsion tube seats in the carb bowl.

AS fishnwiz mentioned above there is good info in the Techs section on this. Hope it helps you.

Keep us posted on your results.

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rfsmith1952

Thanks. I do believe the needle valves were different. I will double check that. Any reason why it would run ok with the choke on, and stall with the choke off? Pulling in air somewhere?

Thanks, I am learning. A few years ago, it was the equivalent of an 8 mile force march to get into the Shift-Shaft drive/neutral control and repair that. Then it took me a trip from PA to IN and back and a few tries to get the hydro installed and running right. So this 4 pound carburetor is easy compared to that. I even made a gasket. last time I made a gasket was about 1968.:D:D

The big thing is I know you guys will have the answers.

Jim: Early spring according to Phil...

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rfsmith1952

Taking apart the Carburetor was not nearly as intimidating the second time. I think I see now how it works, but I'm a little fuzzy on where it gets it's vacuum, and how the fuel is vaporized. I got it back on - no leaks - and after adjustments, starts and runs good at all rpm. The emulsion tube was not in all the way. Thanks for all your help.

So for those who never took part/rebuilt a flo-jet carburetor:

Watch Zippo's movies

Make the screwdriver tool to remove the tube

Take the tube out first, before taking the carb apart

Be very careful of the governor, its' springs, and it's linkage.

clean, clean, clean

Seat needle valves gently.

Check float valve by blowing air in the carb inlet while carb is upside down. Your breath may not lift the float, but about 90 psi will open it like a champ if it's seated right.

For starting: back the big needle valve out a turn and a half, back the little one out only about 1/2 to 3/4 turn.

Make sure your choke is actually in the position you think it is. I marked the back of the carb and the end of the shaft with the closed position.

When adjusting, remember the positions of the throttle stops, cable stops, and linkage may all be be significantly different if the guy before you adjusted his way to keep the ole girl running.

I have no idea of any easy way to get that hose back in. I poked it, greased it, squeezed it punctured it, and while it's in, it's not right. I think it's just a breather though.

That was fun. I'd like to try it again.

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huffy
quote:Originally posted by rfsmith1952

I have no idea of any easy way to get that hose back in. I poked it, greased it, squeezed it punctured it, and while it's in, it's not right. I think it's just a breather though.


id="quote">
id="quote">Do you mean the tube between the breather and that little pipe between the air filter and carb?

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fishnwiz

AWESOME JOB!!dOd dOd dOd dOd

The more (Carbs) you do, the better you get at it! But be aware that there is always going to be those one or two carbs that are just going to be a headache no matter what you do to them...Just don't let THOSE get you down!

Wiz

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fishnwiz

Just a thought..If you are having a major problem with getting the breather hose back in are you sure that you don't have the ends reversed? It should slide right back in.

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midnightpumpkin

Bob,

I keep a couple of the rubber breather tubes on hand. New ones are not very expensive and are very pliable. Old ones, as you know, get hard and are difficult to install.

Both ends are the same on a new one. After time and heat from the engine, they tend to take on a form.

John U

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rfsmith1952

I was thinking about cutting the hose midpoint between engine and carb, then inserting a smaller diameter plastic or rubber hose inside the two ends and securing with hose clamps if necessary. But John has the right idea..get a new one.

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huffy
quote:Originally posted by rfsmith1952

Thanks, Wiz @Huffy, it's a hose that goes from under the air cleaner to the engine.


id="quote">
id="quote">I just bought one not too long ago. They're only about $4.50.Something I've noticed about the old ones is that once they harden up, they have to be in exactly the same position as when you removed them to get them back in. Sometimes you gotta rotate them to get the angle exactly right before they'll pop in.

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