Fixing Needle In Carb

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  #1  
Old 10-27-07, 06:43 PM
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Talking B&S 15.5 hp Problems

Just recently used 10 yr old craftsman tractor to haul dirt around yard (using craftsman cart). Think I might have put a little too much pressure on the engine. Started marking a banging noise from the front end (originally thought it was the drive pulley/bad belt ). A few days later after the tractor had been sitting in my garage I began to smell gas in the garage but couldn't pinpoint its orgin. I then noticed the strong smell coiming from the air box of the tractor. Never had experienced this before. When I pulled it outside to start (had to jump off my car due to a dead battery) it wouldn't turn over and the flywheel was hesitating (almost as if it was seized). It would turn then stop (I know that I Had a good connection with the cables because I could hear the strain on my car). I then looked in the front and saw gas seeping out of the inside of the muffler. NOT GOOD. I think the cylinder is flooding with fuel and one of the valves is open. Before I even waste my time taking the head off, someone recommended checking compression to see id it's blown. Although she did have a slow leak out of the bottom of the dipstick, it had oil in it.
 
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Old 10-27-07, 07:33 PM
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You didn't tell us what the engine numbers are, so untill the pros get here, run to the garage & post them. It'll help them a lot. I think the float has sank due to a hole in it or dirt between the needle & seat. Grab the numbers & the guys here will get you dialed in in no time!! Roger
 
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Old 10-27-07, 09:18 PM
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Don't pull the head...it's not an engine problem. It's a carburetor problem. The carb is leaking fuel into the engine because the needle is not sealeing in the seat. Repair this, drain the gas-thinned oil and refill with new oil, and you should be set.
 
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Old 10-28-07, 05:36 PM
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The Engine is a Briggs and Stratton 15.5 hp

Model Number: 28N707
Type Number: 0173-01

Carb problem? What I'm worried about is the flywheel not spinning freely when I attempted to jump it. I have read that gas soaked engine oil destroys the lubrication qualities of the engine oil and could lead to a seized engine. I am worried that this is what happened to me (hopefully not the racket that I heard from the engine area!) Hope not. Appreciate all the advice anyone had to offer before I get into this project! Thanks
 
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Old 10-28-07, 07:25 PM
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Yeah, and the gas is what is causing the flywheel to not turn.

I don't know what the banging was...could be a number of things, but you'll need to fix the fuel leak and clear the cylinder before you can find out. The fuel has filled the cylinder, so the piston can't move up the cylinder. (liquid doesn't compress like air does). Fix the leak, pull the spark plug, spin the engine with the plug wire out of the way so it won't spark and the mower outside with a rag in front of the lug hole. Watch out, it will shoot gas out like crazy. Then drain the oil and refill with new, and crank it up. If it makes a noise after this, you can determine where it's coming from. Usually a banging is from engine mounting bolts.
 
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Old 10-29-07, 07:11 AM
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thanks! I'll get going on that this week before the New England temp gets too low! Suggestions on the carb? Just order a needle repair kit or should I go for an entire carb overhaul? Thanks

A guy at work actually just went through the same thing with his mower. I can't remember if he said he just replaced the needle or did a complete overhaul on the carb. Any more suggestions are always appreciated!
 
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Old 10-29-07, 07:50 PM
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Fixing Needle In Carb

Posted a thread earlier about B and S having problems. With much help (by Cheese) I hopefully pinpointed the problem to the needle in the carb. The engine all of a sudden started smelling really badly of gas, and when I attempted to crank it gas came out of muffler. With help from this site I was told that I more than likely the needle wasn't sealing properly. Took the tractor apart today, and after cleaning the whole thing I drained the gas tank and lines. I then pulled the plug and rotated the flywheel by hand and some gas came out. The fun part was draining the oil, or should I say gas! The gas-soaked oil came spilling out and I let it drain for a while. I then refilled the tractor with oil.

My question is, how do I fix the needle problem?? I am pretty mechanically inclined so any advice that will get me started in the right direction is appreciated. Also, does anyone know where there is a Briggs and Stratton repair manual online or does anyone have the PDF??? One my Motorcycle forum someone gave me the entire service manual for my bike. Thanks

Model :28N707
Type: 0173-01
B and S 15.5 hp
Off Craftsman 1996 42"
 
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Old 10-29-07, 11:57 PM
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I merged this thread with your previous thread. In order for us to keep from getting confused, and to keep all info in one place, please use the reply button.

You won't know what kind of repair will need to be done without looking. Remove the bowl and have a look. Most likely you can clean out the bowl, replace the needle and go from there. If it's full of junk or varnished up, you'll want to clean and recondition the whole carb.
 
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Old 10-30-07, 05:29 AM
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Originally Posted by cheese View Post
I merged this thread with your previous thread. In order for us to keep from getting confused, and to keep all info in one place, please use the reply button.

You won't know what kind of repair will need to be done without looking. Remove the bowl and have a look. Most likely you can clean out the bowl, replace the needle and go from there. If it's full of junk or varnished up, you'll want to clean and recondition the whole carb.

Cheese - I am now joining this thread, because I have the same problem exactly on my 18 HP B&S. You pinpointed my problem in another thread about my Tractor not being able to move due to the brake being stuck. You were exactly right!!! And this was going to be my next problem for you to help with!!!

Anyways, Where is this needle that I need to clean? Is it hard to get to??

LostinWork
 
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Old 10-30-07, 11:17 AM
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The carb is WALBRO where the air intake and elbow connect on the sides. How do I get this thing apart so I can get to the float and needle??
 
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Old 10-30-07, 11:41 AM
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The easiest way to work on this carburetor (and any one for that matter) is to remove it from the engine and service it on the bench. Remove the air cleaner cover, remove the air filter, remove one screw in the air cleaner compartment (gold in color) and the two nuts that hold the cleaner to the carburetor body and possibly one screw that holds the choke control cable bracket to the cleaner, if so equipped. Then remove the two stud screws (that the two cleaner nuts came off of) and the carburetor will then be loose from the intake manifold. You will have to twist the carb in order to remove the throttle linkage and you may have to do the same for the choke control, if so equipped.
 
  #12  
Old 10-30-07, 04:45 PM
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ok, pulled the air cleaner off and the carb. kept it as clean as possible. pulled the bowl, float and needle off. pulled the emulsion tube out the needle jet valve. didn't have a carb tool so I had to use a regular flat tip. when i was unscrewing the needle jet valve, i damaged it a little bit due to how soft the brass was. do i need to replace this thing know? should i get one of those carb tools.

lastly, how do i get the brass seat out of the carb. in the manual it says you need a special tool. i have a rubber tip needle that goes in a brass (appears to be pressed fit) seat. someone recommended taking that to a shop to be done? I need to get this thing out.
 
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Old 10-30-07, 08:24 PM
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Very rarely does the brass seat cause a leak, and I always leave them in place. I don't reccomend changing it...just the needle.

When you removed the jet nozzle, I assume you just buggered up the slot where the screwdriver fits? If so, no problem, just take care putting it back in.
 
  #14  
Old 08-14-08, 07:53 AM
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Replace the Seat as well as the needle

If you have a Walbro carb with a brass seat replace the seat as well as the needle. If you can't get the seat out take the carb to a mower shop. They can do it for you for a small fee usually. Call around to see if they have time....
 
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Old 08-14-08, 10:06 PM
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This thread is nearly a year old, but even so, I still maintain that the seat rarely gives trouble and replacing it can cause more problems than leaving it alone. As a last resort, then ok, but for a general overhaul, clean the seat well and leave it there.
 
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