Carburator problms on 9n ford

Zookeeper54 · Mar 27, 2023

I cannot figure out if this is a carb problem or not. My 9N will drop rpm sporadically when moving heavy objects, going uphill, or just idling. If I pull the choke out and push it back in, it will pick up rpm. My husband was working on the tractor but he has been in the hospital for the past 5 months, so he can not help right now. I have never worked on a carburetor till now. Can anyone help give ideas or?

Jamisonj1 · Mar 27, 2023

post a picture
Of yourself..& maybe carb, if you like

Jamisonj1 · Mar 27, 2023

post a picture
Of yourself..& maybe carb, if you like

used red MN · Mar 27, 2023

Hello ZK welcome to YT! Quite sorry to hear your
husband is having medical problems!

All your symptoms except maybe the one at idle sound
like you do not have an adequate fuel supply to your
carburetor. There should be a drain plug on the bottom
of the carb get a clean jar. Pull the plug and catch what
comes out. It should also continue to flow steady and
not slow down to just dribbles. To be correct the carb
should drain out a pint of fuel in 3 minutes. The reason
for using the jar is so you can look at the fuel that
drained out after it settles a bit. What ever crud you
see in the jar is also in the carb, should be squeaky
clean for everything to work right. If the gas flow is not
enough then you need to unhook the line at the
carburetor. See if the flow is adequate out of the line, if
it is good you need to check out the screen in the inlet
fitting of the carburetor. The 1st link shows what one
looks like. If the flow is NOT good out of the line you
need check the sediment bowl which is the small clear
glass bowl below the gas tank which includes the fuel
shut off. Originally it would have had a screen in the
top of it that screens the fuel before it can go in the
line to the carb, the 2nd link shows the screen. With
the sediment bowl off. If gas flow is not good there you
need to remove the sediment bowl base out of the tank
and see what is plugging the place where the gas
enters the sediment bowl base to exit the tank.
Carb elbow screen

Sediment bowl screen

DanielW · Mar 28, 2023

The advice from Used Red is spot on. One more thing I might mention: It's pretty common for the tank to get plugged
up right at the sediment bowl - especially if your N has the original filter atop the bowl (in the tank). Often it
allows enough flow for idling & light jobs, but not enough for heavy use. Sometimes it's hard to diagnose -
especially if it's something floating around in the tank that sometimes clears off. The fuel level in the carb will
be fine for the most part, but drop for a quick second and cause the engine to die.

See this thread below and note my post where I mention the old trick of threading a barbed fitting into the carb
drain port and using some clear fuel line in a 'U' shape from the fitting to gauge level in the carb while running.
Also see the original poster's last reply, where he noted that's what the problem was, and how he noticed it. His
tractor wasn't an N, but everything about it would apply to your case.
Carb Diagnosis & Solution

JMOR · Mar 28, 2023

ScottNC · Apr 1, 2023

If I overlooked this is other comments, sorry. There is a vent hole in the top of the tank forward of the fill cap that can, over time clog with dirt. If this hole is clogged, when fuel leaves the tank it will create an ever increasing negative pressure in the tank until fuel flow is reduced or stops. Symptoms vary with the amount of fuel in the tank and match the fuel flow restriction in the tank/sight glass or carb inlet mentioned by others.

Tim PloughNman Daley RIP · Apr 3, 2023

Welcome aboard ZOO! Our thoughts & Prayers are with you for a speedy recovery for your husband. Good advice already given by a few here, but there are a few tests you
can do before pulling the carburetor off for a rebuild. First, I advise never to use rubber, plastic, neoprene, nylon, copper, or aluminum for the fuel line. Always
use the OEM style 1/4 steel lines. Correct lines are made pre-bent for your tractor. Here is the correct info for fuel issues. Next, be sure you have the Sediment
Bulb Valve Knob Turned OPNE 2 FULL TURNS.I have rebuilt many FORDS in my life, used to have my own shop til 2020. I will rebuild your 9N Carb to exact OEM Specs, you
pay for parts and shipping only. My email is open -see LINK in lower RH corner.

FORD N-SERIES TRACTOR FUEL SYSTEM & POSSIBLE CAUSES OF NO FUEL:
Probable NO-GO fuel issue causes are: plugged vent, plugged screens, plugged sediment bulb, dirty gas tank, dirty carb, and more. There are three OEM screens in the
fuel system. Two are on the Sediment Bulb Assembly; the 3rd is on the brass elbow inside the carb where the fuel line connects to. SEE PICTURES. The gas tank vent is
on the top of the tank. It is a chore to get it unplugged as much needs to be removed first. The tank is attached to the bottom of the hood. It is a a few hours to
remove these parts, and only takes a minute to unplug the vent hole. I suggest you leave this alone for now and do the Fuel Flow Test first. The Sediment Bulb screens
get plugged often and the carb brass elbow fuel inlet is often neglected when doing routine maintenance. Clean the glass jar screen and elbow screen first, leave the
tank/vent and Bulb Assembly attached for now too.

SEDIMENT BULB, SCREENS, & CARB FUEL INLET BRASS ELBOW:

DIRTY, USED BRASS ELBOW FUEL INLET:

CARB & ADJUSTMENT; FLOAT LEVEL POSITION; FORD G0/NO-GO GAGE #9550-D SHOWN:

USE A 9/32 drill to set at mean value. Later manuals say to set float to 1/4 so you can use a 1/4 drill too as a GO gage.

FLOAT w/NEEDLE & VALVE:

M/S TSX CARB INTERNAL OPERATION VIEW:

CARB FUEL ISSUES & ADJUSTMENTS:
The carburetor needs to be properly adjusted when the engine is up to operating temp meaning hot. It takes a few tries and make 1/8-1/4 turns at a time and WAIT til
engine speed catches up. Is the Sediment Bulb Valve Stem open 2 Full Turns when you start it up? Did you remove the brass fuel inlet elbow and clean the screen? A
stuck float or float needle may cause excess fuel to leak out and you will get the gas in the air intake port so pull rubber hose and see if it is wet. Next, perform
the fuel flow test. The Main Adjustment and Idle Air screws are set to 1 turn out. Idle (throttle) initial setting is throttle plate just opening. You need to do this
with carb on the bench you cant see the plate when attached to manifold. Idle speed is set to nominal 400 RPM but unless you have a Proofmeter on later 8Ns and up,
will have to guess or use an RPM tester.

CARB FUEL FLOW TEST:

ENGINE COLD! Find a 1-Pint Mason Jar and place it inside an empty coffee can, then position the can under the carb. Loosen the 7/16 hex nut on the fuel line at the
carb brass inlet elbow and gently lift and slide the fuel line off to the side so it points down into the can and jar. Open the Fuel Sediment Bulb Valve 2 Full Turns.
Observe the fuel flow is a steady stream and you fill the jar in 2 minutes. Any sputtering, hesitation, or failure to fill gas in the Mason Jar indicates the problem
is upstream on the Sediment Bulb, in the carb, or in the gas tank itself. If Test passes, connect the fuel line and repeat using the carb drain plug in bottom. This is
an NPT tapered pipe plug thread; it's not a standard thread size, so do not try to use anything other than that to chase threads or replace. If this portion of the
test passes, reset the drain plug, leave it alone, and move on to carb leaking fuel through the air intake port. Remove rubber hose connecting carb to air cleaner
tube. If it is wet with gas the float may be stuck or the level is not set right. The float is brass and soldered on in two halves. If it gets punctured or sprouts a
leak, fuel can fill it and bog it down. Carb Air Intake Throat should be dry. Either way, wet or dry, it is time to pull the carb and get into a total cleaning and
rebuild.

Tim Daley(MI)

Carburator problms on 9n ford

Zookeeper54

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Jamisonj1

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Jamisonj1

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used red MN

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DanielW

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JMOR

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ScottNC

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Tim PloughNman Daley RIP

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