Carb baffled newbie with a 1950 8N

SNAL

New User
Hello all! I'm new to the forum, and recently acquired a 1950 8N. It had all sorts of issues from sitting for several years. I built a new wiring harness, new radiator, new points/plugs/wires/cap/rotor/condenser.
She's getting fire, and will run as long as I keep giving her shots of starting fluid, but will not stay running when I stop the spray. Rebuilt the original carb with the exception of the main jet that I don't have the right screwdriver for removal. I did CLEAN the main jet, ran a wire through it, sprayed all passages with cleaner and air.
I'm getting fresh fuel to the float bowl.
Carb has been off/on...opened up and double checked in every possible way that I can check it....but she's still not flowing fuel.
Idle mix has been 1 to 2 turns out, 1.5 to 4 turns out on main mix.
I'm baffled!

This post was edited by SNAL on 07/29/2021 at 10:53 am.
 
(quoted from post at 13:50:17 07/29/21) Hello all! I'm new to the forum, and recently acquired a 1950 8N. It had all sorts of issues from sitting for several years. I built a new wiring harness, new radiator, new points/plugs/wires/cap/rotor/condenser.
She's getting fire, and will run as long as I keep giving her shots of starting fluid, but will not stay running when I stop the spray. Rebuilt the original carb with the exception of the main jet that I don't have the right screwdriver for removal. I did CLEAN the main jet, ran a wire through it, sprayed all passages with cleaner and air.
I'm getting fresh fuel to the float bowl.
Carb has been off/on...opened up and double checked in every possible way that I can check it....but she's still not flowing fuel.
Idle mix has been 1 to 2 turns out, 1.5 to 4 turns out on main mix.
I'm baffled!

This post was edited by SNAL on 07/29/2021 at 10:53 am.
ill gas flow out bowl drain plug? Is venturi installed with correct end up?
 

Hello,

Is your carb a Marvel Scribner TSX33? I assume you checked fuel flow out of the gas line when disconnected from carb. And, I assume you cleaned the inlet screen on the carb. Is your float needle stuck closed? Are the small holes on the sides of the main nozzle open?
 
All internals are new except the main jet, which is clean, I just didn't have a driver small enough to remove it.
Original Marvel carb

This post was edited by SNAL on 07/29/2021 at 11:34 am.
 
NEWBIE: Is your 8N a front mount or side mount unit? Is it 6V POS/GRN or 12V NEG/GRN? Do you have The ESSENTIAL MANUALS? The Main Seat, gasket, and needle valve are probably one of three most important parts to replace on a rebuild. The brass seat requires wide, flat blade screwdriver to insert or remove. Many booger this up attempting with the wrong tool. A standard screwdriver will not work. I use a common chisel tool that has a flat, wide blade and easily will function on the seat without risk of damaging -see the third tool from the right in my picture. I use my old guitar strings for cleaning out orifices and avoid drilling, reaming, or reboring any holes. I set the float using a 9/32 drill as a gage. Many say float is set at 1/4 but the OEM Spec is GO .26 and NO-GO .297 so use the 9/32 as a close enough to mean size. The fuel filter elbow is part of the standard PM and often is the cause of plugged up fuel flow. When carb is assembled after rebuild, set the needle jets to specs and perform the fuel flow test before starting up engine and if it passes, continue with adjusting. This all hinges on having the wiring all correct for whatever system you are using. Lastly, invest in the Essential Manuals and read religiously.


FORD N-SERIES TRACTOR- MARVEL SCHEBLER CARBURETOR & SETTINGS:
DU4UJCMl.jpg
CXupU1bl.jpg
xyove8Il.jpg
IXC1KzMl.jpg
wGCNoCil.jpg
pGzioxLl.jpg

MY MARVEL-SCHEBLER CARBURETOR REBUILD TOOLS NEEDED:
WKXSWDCl.jpg

FORD CARB P/N 8N-9510, M/S TSX-241, MAIN JET NEEDLE VALVE AND SEAT:
3krZSx6l.jpg
*NOTE: For Main Jet Seat and Needle Valve removal, get a standard wide blade chisel tool as shown, 3rd from Right in above pic.


FORD/MARVEL-SCHEBLER CARB BRASS ELBOW FUEL FILTER 9N-9553:
v8ej8sZl.jpg
*NOTE: One of the three filters in the fuel system that requires frequent cleaning/PM.



FORD 8N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:
2a28IGzl.jpg

Tim Daley(MI)
 
Dist. is side mount. I have all of the manuals.

I'm beginning to think that maybe, possibly, the new main gasket might be blocking a passageway. Dunno, just so baffled that I'm trying to think of anything.
The fuel line elbow on this one didn't have a screen, but, every time I've had this thing off there was never the slightest amount of trash in the bowl.
I'm out of town, and won't be back till Monday to tinker more.

This post was edited by SNAL on 07/30/2021 at 09:24 am.
 
(quoted from post at 12:23:32 07/30/21) Dist. is side mount. I have all of the manuals.

I'm beginning to think that maybe, possibly, the new main gasket might be blocking a passageway. Dunno, just so baffled that I'm trying to think of anything.
The fuel line elbow on this one didn't have a screen, but, every time I've had this thing off there was never the slightest amount of trash in the bowl.
I'm out of town, and won't be back till Monday to tinker more.

This post was edited by SNAL on 07/30/2021 at 09:24 am.
his picture is not your carb, but illustrates that fuel must get thru power adjust needle seat before it can reach main jet & nozzle. Without this flow path, there will be no fuel for idle or main power.
nencuC6.jpg
 

Looks just like my carb.
That jet is the only item that did not get replaced, but I cleaned it, ran a wire through it, and blew out all passageways after an overnight stay in the parts cleaner followed by multiple rinses/sprays with carb cleaner. I did not have a screwdriver small enough to get to that jet. I even put a bore light down the hole above that jet and looked through the small drain plug hole to see that the jet was clear/clean.
 
(quoted from post at 12:50:39 07/30/21)
Looks just like my carb.
That jet is the only item that did not get replaced, but I cleaned it, ran a wire through it, and blew out all passageways after an overnight stay in the parts cleaner followed by multiple rinses/sprays with carb cleaner. I did not have a screwdriver small enough to get to that jet. I even put a bore light down the hole above that jet and looked through the small drain plug hole to see that the jet was clear/clean.
have never seen a power adjust needle seat that screwed in....only pressed in. Main power jet at base of nozzle screws in.
8to0OvS.jpg

tYJea4g.jpg
 
(quoted from post at 13:07:48 07/30/21)
(quoted from post at 12:50:39 07/30/21)
Looks just like my carb.
That jet is the only item that did not get replaced, but I cleaned it, ran a wire through it, and blew out all passageways after an overnight stay in the parts cleaner followed by multiple rinses/sprays with carb cleaner. I did not have a screwdriver small enough to get to that jet. I even put a bore light down the hole above that jet and looked through the small drain plug hole to see that the jet was clear/clean.
have never seen a power adjust needle seat that screwed in....only pressed in. Main power jet at base of nozzle screws in.
8to0OvS.jpg

tYJea4g.jpg

The jet in your previous post/pic is the one that I couldn't reach to change. I think I may have overlooked the jet below the emulsion tube. Is that the main jet?

This post was edited by SNAL on 07/30/2021 at 11:26 am.
 
(quoted from post at 12:31:16 07/30/21)
nencuC6.jpg

So "this" one is pressed in, and not serviceable? I thought this was a screw-in.
I'm thinking that I missed the main completely, and you have brought that to my attention!!!!!
 
(quoted from post at 14:36:43 07/30/21)
(quoted from post at 12:31:16 07/30/21)
nencuC6.jpg

So "this" one is pressed in, and not serviceable? I thought this was a screw-in.
I'm thinking that I missed the main completely, and you have brought that to my attention!!!!!
es. That was my thinking.
 

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