Ford 8N having trouble starting -- many troubleshooting steps take -- suggestions?

[DJ54]

After hearing it run, faltering, then looking back at the pics of the carb apart, I noticed a couple of things. I know you said you blew air through the jets, but I'd be tempted to remove the main nozzle (brass tube with hex nut you can see in the throat of the bottom half) and check the little cross drilled holes for a speck of something in them. Use some spray carb cleaner if there is. Heck, I've pulled a wire, out of a wire brush to clean them. They are small holes..!! Looking at the pic of the fuel filter, there seems to be quite a few particles in it, and some may have passed through at some point.

The other thing I noticed. Maybe it's not that I think, but appear's to be a split/tear in the gasket on the top half of the carb, where the halves join. Look between the venturi, and to the left, to that next little port. Looks like a black line. Either pressed in there, or the gasket is split. I reckon' a small air leak there could give you fits.

 

[94BULLITT]

Unhook the hose between the carb and air cleaner and see how it runs. If it runs good you have a clogged air cleaner or possibly frozen or too much oil in it. If it does not take the carb apart and clean everything very carefully. If you take the carb apart post pics of the dis-assembly and assembly. Something is wrong when you can turn the main jet all the way in and it does not change the running of it. For the preliminary adjustment it should be backed out 1 turn and same for the air/ fuel. It is also idling way too high.

 

[DJ54]

Yeah, I thought about the air cleaner too, just didn't post it. I had a TO-20 Fergie that a mouse packed the oil bath air cleaner full. But not seeing the exhaust, and seeing if it is running somewhat rich was the reason I guess. And running the main in all the way, and not shutting off the fuel, or at least getting some falter there..?? Hmmm... I'd have to take a peek at the needle and seat on that too. Possibly a PO didn't know when to say when, running it in against the seat..?? Is there even a tip left on the needle..?

 

[PorkChopsMmm]

You all offered some good suggestions, but I think I should clear up some of the work that was done/troubleshooting that has already been tried.

After hearing it run, faltering, then looking back at the pics of the carb apart, I noticed a couple of things. I know you said you blew air through the jets, but I'd be tempted to remove the main nozzle (brass tube with hex nut you can see in the throat of the bottom half) and check the little cross drilled holes for a speck of something in them. Use some spray carb cleaner if there is. Heck, I've pulled a wire, out of a wire brush to clean them. They are small holes..!! Looking at the pic of the fuel filter, there seems to be quite a few particles in it, and some may have passed through at some point.

The other thing I noticed. Maybe it's not that I think, but appear's to be a split/tear in the gasket on the top half of the carb, where the halves join. Look between the venturi, and to the left, to that next little port. Looks like a black line. Either pressed in there, or the gasket is split. I reckon' a small air leak there could give you fits.

Thanks for the feedback DJ54. The carb has been completely rebuilt at this point, just a few days ago by the mechanic. He took it all apart, tested different components, we replaced the float (the floats were dented and he just wanted to be sure), and all new gaskets were put in. While it was disassembled we blew carb cleaner out through the jet holes, blew air through the float open/closed, etc. and it all looked good. We also cleaned out the screen from the fuel line at the carb and it all looked good.

The inline fuel filter was removed a long time ago

Unhook the hose between the carb and air cleaner and see how it runs. If it runs good you have a clogged air cleaner or possibly frozen or too much oil in it. If it does not take the carb apart and clean everything very carefully. If you take the carb apart post pics of the dis-assembly and assembly. Something is wrong when you can turn the main jet all the way in and it does not change the running of it. For the preliminary adjustment it should be backed out 1 turn and same for the air/ fuel. It is also idling way too high.

This wasn't in the video, but when I was adjusting the carb I ad the hose off of the air cleaner. It gave me the room I needed to adjust the idle screw without burning my hand on the manifold or exhaust. There was no difference with the hose off of the air cleaner. That being said, it is completely filthy and needs to be cleaned out but I don't think that is the problem here.

I agree with your comments about the main jet. I propose I do the following steps tonight while the tractor is running a) remove the hose from the carb b) dial back the main to one turn to open and the idle needle to open turn open and c) adjust the idle screw down to a more normal idle. I will record this so you can see if doing these adjustments changes anything.

Yeah, I thought about the air cleaner too, just didn't post it. I had a TO-20 Fergie that a mouse packed the oil bath air cleaner full. But not seeing the exhaust, and seeing if it is running somewhat rich was the reason I guess. And running the main in all the way, and not shutting off the fuel, or at least getting some falter there..?? Hmmm... I'd have to take a peek at the needle and seat on that too. Possibly a PO didn't know when to say when, running it in against the seat..?? Is there even a tip left on the needle..?

The exhaust doesn't look sooty, white, or black. This is parked on snow and I didn't see any soot or anything on the snow when I was done with my tests. When the carb was apart just a few days ago I checked all of the needles and they all looked good -- not broken or anything. That could have definitely changed but I hope not. If adjust the idle, air, and fuel doesn't have much of a difference I think it's time to crack into the carb again.

If it didn't cost $25 for a service visit plus $25 an hour I think I would have my "mechanic" back out again with his carb to try on my tractor. It would be interesting to see if there was anything difference.

Thanks for the help guys. Much appreciated.

 

[PorkChopsMmm]

Do you have, or know someone with a compression tester, just think it would be a good idea to make sure (at this point) you don't have a dead or low cylinder. We have dial up so it just takes to long to download thevideos
.

I don't have one but maybe I should buy one or borrow one. I will try to do that today. Do you just take out all of the spark plugs and do one cylinder at a time?

 

[GPintheMitten]

Here's a youtube on compression testing. He also has a leakdown check video. I thought he did a good job explaining.

Compression Testing and What You Can Learn From It - EricTheCarGuy - YouTube

Here's a video on a Model A engine. Model A Ford Compression Test - YouTube

 

[94BULLITT]

I don't have one but maybe I should buy one or borrow one. I will try to do that today. Do you just take out all of the spark plugs and do one cylinder at a time?

Pull the plugs, leave the key off, gas off and open the throttle all the way and screw the gauge in a cyl. Let the motor crank over til the compression hits atleast 3 times. Record your findings. A auto parts store may rent one.

 

[Soundguy]

do a dry test and then a wet test IF you comp test her.

that said.

there is a problem with the carb if you can screw the main needle all the way out OR in.

allt he way out and the needle WILL come out.

that's way, way too rich of a setting.

the sputtering is generally a lean condition...

does it still sputter with a lil bit of choke?


did you moke sur ehte choke flap is installed correctly..

same witht he throttle butterfly.. is it installed well and not loose.. and fit well?

 

[PorkChopsMmm]

I am going to borrow a buddy's compression tester tomorrow and give that a go.

Soundguy, thanks for the advice. Looks like I will be pulling the carb tonight :mur:

I will take pictures and give you guys a look at the main needle. I agree -- it's weird that I can turn it a whole bunch and nothing is happening.

does it still sputter with a lil bit of choke?


did you moke sur ehte choke flap is installed correctly..

same witht he throttle butterfly.. is it installed well and not loose.. and fit well?

I feathered the choke a little when starting her but I didn't touch the choke while she was running. I will try that tonight before pulling the carb. I'll check the choke flap and the throttle butterfly tonight. The "mechanic" was the last guy to touch the carb. I imagine the choke flap is working well because I could hear/feel it working when feathering it just a bit when starting the tractor.

More pics to come tonight. I am dying to buy a 3 point carry all and built it up but I am hesitant until I get this baby running right!

 

[Soundguy]

i wouldn't assume anything that mechanic did was good or correct..

also.. the choke plate can be installed that the air bypass flap is BACKWARDS, and non functional.

when you get the carb off.. engage the choke.. make sur ethe lil flap opens in toward the carb.

anyway.. before you do that. try a lil choke when it's sputtering.


I'm thinking you have a very serious fuel restriction / leaning going on.

assuming ( is it? ) it is getting good fuel flow TO the carb.. then it's IN the carb.

the fact the main adjustment has NO effect means there is a restriction IN that circuit.

if you look at the carb diagram at the bas wher ethat needle goes.. ahead and to the right of it is the jet. there is a cross hole near there too

also make sur ethe venturi is in right side up!