Briggs 7hp Horizontal Mixture Screw Fuel Leak

["Manic-Mechanic" 1,228]

I have two piece flo jet carb which has been rebuilt and all the leaks stopped besides the one last leak from the metering screw under the emulsion tube. I have reset the emulsion tube repeatedly and even replaced the bottom carb. I have tried two different emulsion tubes so far. I finally have the drip slowed but still is a drip. I don't want to break the emulsion tube inside the bottom half from excessive tightening. I am tired of this ongoing leak issue and about ready to just get another carb. I have combed through all manuals and technical diagrams onlt this one has a small bit of information on this type of leak. However, I have never failed at getting one of these to function correctly, so any input would be greatly appreciated.

 

 

CH_V_Carburetion.pdf

Carburetion_Troubleshooting_Detail_Reference_Guide.pdf

Edited April 14, 2019 by oldman

[classiccat 548]

I assume you saw Zippo's video on it.   (this has worked for me on my Flo Jet from a '69 7hp briggs)

 

Watch in youtube, the 1st comment contains links to some service bulletins (regarding lapping compound & teflon washers).

 

 

[ebinmaine 71,091]

I have very little experience messing with these type of carbs.

Teryl dactyl on YouTube has a video about fixing this, I think.

 

Perhaps @wallfish or @Stepney could comment.

[gwest_ca-(File Mod) 11,281]

One fix for the leaking nozzle is to add a teflon washer to seal the taper on the seat. The washer comes in a small kit that was intended for something else.

I found the Permatex pipe thread sealer with teflon works. Make sure the nozzle is clean and dry so the sealer sticks to it. Use a toothpick to apply a small layer of sealer to the tapered seat only. Sealer comes in small plastic bottle with a brush.

 

https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-thread-sealant-with-ptfe/

 

Garry

["Manic-Mechanic" 1,228]

1 hour ago, classiccat said:

I assume you saw Zippo's video on it.   (this has worked for me on my Flo Jet from a '69 7hp briggs)

 

Watch in youtube, the 1st comment contains links to some service bulletins (regarding lapping compound & teflon washers).

 

 

 

I've seen this and it's great, however, I don't have a leak in the two areas mentioned in this video. I have a leak dripping from the metering screw itself and there isn't a video or instruction on stopping that.. Even the diagram I posted shows the leak coming out and around to the weep hole or air entry, not a leak out the metering screw.

[ebinmaine 71,091]

1 minute ago, oldman said:

not a leak out the metering screw

Keeping in mind that I'm not super familiar with these Carburetors in particular but I do understand how wicking of fluids works, is it possible that it's actually leaking higher up in the system and simply running down that component?

 

["Manic-Mechanic" 1,228]

Just now, ebinmaine said:

Keeping in mind that I'm not super familiar with these Carburetors in particular but I do understand how wicking of fluids works, is it possible that it's actually leaking higher up in the system and simply running down that component?

 

I've addressed that possibility and haven't found a solution, yet. I did notice the leak slowed a bit with a better seal on the emulsion seat, so again I will work on the seat of the nozzle and bottom carb. Problem with tightening back and forth is it gets stuck when it is loosened and breaks inside the bottom carb, then the bottom is junk. Once a nozzle breaks an easy out won't work and drilling an tapping is futile as well. I have two brand new bottoms and each of them are the same, lapping and teflon, not working. At 50-100 a pop it's getting expensive. So I picked up an older carb off a running engine. No more "new old stock", they are not built well at all.I dare say if this was a profit making venture I'd be backwards twice over! Wicked.......

["Manic-Mechanic" 1,228]

1 hour ago, gwest_ca said:

One fix for the leaking nozzle is to add a teflon washer to seal the taper on the seat. The washer comes in a small kit that was intended for something else.

I found the Permatex pipe thread sealer with teflon works. Make sure the nozzle is clean and dry so the sealer sticks to it. Use a toothpick to apply a small layer of sealer to the tapered seat only. Sealer comes in small plastic bottle with a brush.

 

https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-thread-sealant-with-ptfe/

 

Garry

 

I've tried this as well, This stopped the leaks to vent hole, not the leak out the metering screw. Starting to think the "new old stock" bottoms are not a match somehow and no more of those, as they don't mate with the upper either due to the warped pot metal. I had to make a sealer sandwich with the gasket for that issue. Sealer is great but really difficult to keep "neat", also a bear to dismantle later on. The whole tractor has been extremely difficult to correct, not a wheel horse for sure! Challenging is putting mildly.

["Manic-Mechanic" 1,228]

Ok, I followed all the steps listed above and changed the sealant to PTFE. I "think" 567 worked, then melted afterwards. Not counting chicks before the eggs hatch, but it is dry right now. Appreciate the input.

 

 

Edited April 14, 2019 by oldman

["Manic-Mechanic" 1,228]

I had this functioning great, then it started leaking again? I am puzzled. Maybe it is an air leak in the fuel system? I have another carb but hate to just put this one on the shelf. Maybe polishing the seat some more?