Carb won't stop dripping. What am I missing??

[Charlie (KS)]

1949 8N, with original carb. I cannot get the darned thing to stop dripping.

I'm not a newbie. I've had this 8N, and another besides, for more than 17 years. This particular 8n can be finicky but has always run well. Over the last 16+ years I have read literally thousands of posts on this site. Thousands.

First thing I did when I got it (DOA, out of a field) was rebuild the carb, per instructions from Dell, Bruce, Bob, Zane, Hobo, and others smart guys on this site. I've been in and out of it many times to clean it, and occasionally replaced parts, but not often.

Last fall it started dripping. Pulled the carb, and the float had a pinhole in hole in it. Replaced it, and nothing else. Still dripped. Tried another old float. Dripped. I didn't mess with it when it was cold but this spring I've been trying to fix it again and it is still dripping. It happens so fast after I turn the fuel on I don't even have time to turn it over before there's gas on the floor.

At this point I have had it off and on a half dozen times. I have:

Tried two new needles from kits from Asia, and a supposed "Tisco" needle and seat, bought at a ridiculous price from a seller who implied it was USA-made, (and I must say it looks EXACTLY like the ones from the cheapie Asian kits, they even measure exactly the same with a mike).

When I installed the needles, I was sure to give each a little twist, but not too hard, to be sure they were seating, then let the installed float drop a few times to make sure the needle was falling freely and it seemed to be.

Even though the old seat looked fine I put in the new one from the Tisco set, as well as the little ring gasket beneath. Made sure it was, as Dell used to say, "honked down" good and tight.

Set the new float height with a 9/32 drill bit until it seems I could not get closer to being perfect. I have to say, in the past there always seemed to be a lot of wiggle room with this--it just had to be close but this time I've tried a lot harder.

Shaken the carb once assembled to make sure the float was not hanging up somewhere. It moves freely and seems fine.

Checked that the new float has no hole. It is fine.

Banged on the side of the carb with a mallet.

All I can think of is the needle isn't sealing or is misaligning and hanging up on the side of the seat.

So, is there's anything obvious I could possibly be missing, other than in three tries I have not yet gotten a needle that will seal?

I have rebuilt and tuned SU carbs on my 1960 Austin Healey and, despite their reputation, they have never ever kicked my butt like this!

Have read practically every post on this and don't see what I'm missing. Any ideas? I'm tearing my hair out and I don't have much to spare.

Thanks!
Charlie.

This post was edited by Charlie (KS) on 04/28/2023 at 07:15 am.

 

[HFJ]

carb throat, sintered plug or drain plug?

carb throat is above my pay grade. sintered plug can be replaced i think and drain plug can maybe be tightened, unless it's marginally more mangled than mine was prior to replacement.

 

[Charlie (KS)]

(quoted from post at 21:01:01 04/27/23) carb throat, sintered plug or drain plug?

carb throat is above my pay grade. sintered plug can be replaced i think and drain plug can maybe be tightened, unless it's marginally more mangled than mine was prior to replacement.

Hi HFJ. It is dripping from the sintered plug. Doesn't this mean the carb is flooding?

This post was edited by Charlie (KS) on 04/27/2023 at 10:16 pm.

 

[RM-MN]

Carburetors should not be dripping from anywhere. However, it only takes a tiny piece of crud to keep the float valve from sealing completely. Even a hair alongside that valve will allow enough fuel by to make the carb drip. My father solved this by putting a valve inline near the carb that could easily be closed every time he turned the tractor off as the leakage was so small that the running engine would use more than it was leaking. The real answer is to remove the float valve needle and clean it and the seat.

 

[Charlie (KS)]

(quoted from post at 04:01:07 04/28/23) Carburetors should not be dripping from anywhere. However, it only takes a tiny piece of crud to keep the float valve from sealing completely. Even a hair alongside that valve will allow enough fuel by to make the carb drip. My father solved this by putting a valve inline near the carb that could easily be closed every time he turned the tractor off as the leakage was so small that the running engine would use more than it was leaking. The real answer is to remove the float valve needle and clean it and the seat.

RM, not a bad idea on the little valve. I am skeptical that the fuel system and the carb itself is so full of debris that it would instantly clog a brand new needle and seat, but sure, I can soak the carb again and make there's nothing inside it that would do this. Willing to try anything at this point. Thank you for replying!

 

[JMOR]

(quoted from post at 08:42:24 04/28/23)

(quoted from post at 04:01:07 04/28/23) Carburetors should not be dripping from anywhere. However, it only takes a tiny piece of crud to keep the float valve from sealing completely. Even a hair alongside that valve will allow enough fuel by to make the carb drip. My father solved this by putting a valve inline near the carb that could easily be closed every time he turned the tractor off as the leakage was so small that the running engine would use more than it was leaking. The real answer is to remove the float valve needle and clean it and the seat.

RM, not a bad idea on the little valve. I am skeptical that the fuel system and the carb itself is so full of debris that it would instantly clog a brand new needle and seat, but sure, I can soak the carb again and make there's nothing inside it that would do this. Willing to try anything at this point. Thank you for replying!

n your situation, I might try removing top of carb, rigging a fuel line/hose to connect it to tank, hold it upside down, (gravity on float closing needle/seat) and look for fuel flow.

 

[Charlie (KS)]

JOMR, first, please add yourself to the list of many people I've learned a lot from over the years. Every site has its curmudgeons but overall, there are great people here.

I can follow what you are recommending that I do just fine. But I not following exactly what I should accomplish. I am not the sharpest knife in the drawer, I know that, haha.

If don't get any flow when I do this, it seems that this would prove that the needle is capable of sealing, so the problem is not the needle? Or, if I do this, and manipulate it until it does seal, that this will perhaps cure the problem? I mean, I feel it has to be the needle.

Thank you for your help.

This post was edited by Charlie (KS) on 04/28/2023 at 07:16 am.

 

[JMOR]

(quoted from post at 10:14:47 04/28/23) JOMR, first, please add yourself to the list of many people I've learned a lot from over the years. Every site has its curmudgeons but overall, there are great people here.

I can follow what you are recommending that I do just fine. But I not following exactly what I should accomplish. I am not the sharpest knife in the drawer, I know that, haha.

If don't get any flow when I do this, it seems that this would prove that the needle is capable of sealing, so the problem is not the needle? Or, if I do this, and manipulate it until it does seal, that this will perhaps cure the problem? I mean, I feel it has to be the needle.

Thank you for your help.

This post was edited by Charlie (KS) on 04/28/2023 at 07:16 am.

t could be needle to seat seal and if so, you will be able to see it. If not, you may find a hair line crack in the housing, a leak between seat & housing, etc. At least, you ought to see a leak somewhere and that is more than you have been able to find so far.

 

[HFJ]

(quoted from post at 02:15:24 04/28/23)

(quoted from post at 21:01:01 04/27/23) carb throat, sintered plug or drain plug?

carb throat is above my pay grade. sintered plug can be replaced i think and drain plug can maybe be tightened, unless it's marginally more mangled than mine was prior to replacement.

Hi HFJ. It is dripping from the sintered plug. Doesn't this mean the carb is flooding?

This post was edited by Charlie (KS) on 04/27/2023 at 10:16 pm.

sorry, we're over my pay grade again

I am skeptical that the fuel system and the carb itself is so full of debris that it would instantly clog a brand new needle and seat

several times, no less. that's a lot of crud. my tank is rusty, and a PO installed an inline fuel filter. my fuel system plugged the reserve pickup on a new fuel bowl before i could back out of the barn. but it never plugs my carb

 

[Tim PloughNman Daley RIP]

HiYa Charles, its been a while! Is your carb a Marvel-Schebler TSX-241? The early 8Ns still used the TSX-33, same as the 241 carb but the 241 had some revamped
improvements and the TSCO kits are made for all models now. I only use TISCO kits and wont use any other parts. Get the major Kit, p/n C546V, about $40-$50. The
cheaper kit, BK45V doesnt include any smaller parts, just a few such as the throttle and choke shaft. TISCO also has the OEM style Float Seat, Needle, & Valve. Other
brands sold use the newer style Viton Valve with the extra clip. If you get that clip set wrong it will create issues. Why did someone need to re-invent the wheel and
add another part to the mix? Stupid. The needle valve seat has a gasket underneath. Be sure the old gasket is out and any pieces also cleaned up before inserting a new
one. Did you check the float good? You mentioned a pin hole. Any hole or broken solder joint will cause a pontoon on the float to fill with gas, bog down, and thus not
allow the float to set properly. The bowl will then fill with gas and you will see excess fuel collect thru the carb throat port. Remove the short 4 rubber hose
connector from throat to air cleaner tube and there may be fuel in the throat. This can also cause other problems like running too rich and plug fouling. If this is
the case try replacing the float pontoon assembly with a new one or good used one. You can also try to test it observe test diagram and see if you can detect the pin
hole for repair. Float halves are soldered together. The original carb float had a FORD gage for setting the level with. The mean value was about .281 (9/32) but
later FORD & M/S reduced the value to 1/4. That was used after on all models. You would be OK with the value.


CARB FLOAT TESTER:

OEM STYLE M/S CARB NEEDLE AND FLOAT VALVE, SEAT, & GASKET:

MARVEL-SCHEBLER TSX-33 CARB w/NEW STYLE VITON TIPPED NEEDLE & VALVE, NOTE EXTRA CLIP:

TISCO CARB KIT C546V, FORD N-SERIES/MARVEL SCHEBLER TSX 33, TSX-38, & TSX-241 MODELS:

Tim Daley (MI)

 

[Charlie (KS)]

Thanks, JMOR, that gives me a couple things to try!

Tim, yes, it has been good while, thanks for remembering me. That is very kind, and means a lot. When the tractor is running good I don't tend to write in . Little I could say will ever improve upon the advice you experts give.

It is, in fact, a TSX-241 carb. The old float had the pinhole, so I replaced it with a new one. I have also tested the new one to see that it does not have a hole in it, and it tests good.

I only had a couple of chinesium needles lying around because long ago I'd bought a couple cheap kits to just to get the bowl gaskets. I thought, I've got those needles, why not try em. No they did not work.

A couple weeks ago I bought what was sold as a genuine TISCO needle and seat, (rather than buy a whole $50 kit since I felt, well I don't need the other parts, they were replaced with genuine TISCO parts too long ago).

The supposedly genuine TISCO needle and seat did not fix the drip either. But between your feedback and JMOR's I have a few more things to try. That carb float tester is pretty cool!

Also, Tim, do I correctly understand one should NOT use the needle that comes with the clip?





This post was edited by Charlie (KS) on 04/30/2023 at 02:07 pm.

 

[Joe.S.AK]

Charlie -

Check the old float to find EXACTLY where the hole is. Then check the corresponding surface in the float bowl chamber. If there is a rust bulge it might have "grown" to the point that the float rubbed itself on it - wearing a hole in the old float. Also possible that if there is a rust bulge it could have restricted the float from it's proper movement.

Happened to me.

 

[Charlie (KS)]

Joe, Tim, JMOR, and others

I rigged up a temporary tank and hose, as JMOR suggested and mixed and matched the different needles and seats I had purchased, and finally found the pair that sealed best when the top half of the carb (with float in place) was inverted. Not perfect, and in fact the problem then was that needle would stick a little and not drop instantly.

But figured what the hell, as long as it was sealing. Put it all back together. No drip but I could not get so much as a puff when turning the engine over.

So, took the carb off again and dropped it into the ultrasonic cleaner with a couple tablespoons of Dawn for 30 minutes, blew out the passages with the air compressor and it started right up. No drip for the first time since last fall. Running great now.

By the way, my ultrasonic cleaner does a great job on carbs. You cannot believe the stuff that comes off of them even when they look clean. For me, a little Dawn is preferable to soaking the carb in nasty heterocyclic amine derivative, butoxyethanol, and ethoxylated alkyl amines. Also known as Berryman's. Or spraying carb cleaner all over myself.

Regardless, a trip into the ultrasonic seems, for my carb, to be necessary at least once a year, if not twice.

Thank you everyone, you're great.

 

[Mad Farmer]

(quoted from post at 20:38:58 05/06/23) Joe, Tim, JMOR, and others

Thank you everyone, you're great.

Glad to hear you got it fixed.

While we are talking carbs, it seems a lot of the replacement kit stuff is of poor quality. I tend to reuse whatever original parts appear to be in good shape.

Concerning the floats. They are brass. Anyone repair these with some solder?