8N Fuel Trouble

I am slowly working on redoing all the systems back to the way they are ment to be. This week I endeavored to redo the fuel system. my tractor had the sediment bowl for something else installed on it and a duel line that was comprised of copper, rubber, an additional fuel filter and an extra shutoff valve. in this configuration it ran well. I drove it 10 miles to my brother in-law's and back. tonight after I put the proper sediment bowl assembly, new steel fuel line and new elbow with filter at the carb it started surging. the governor was trying to keep the engine at the set speed and was unable to do it. It is clearly starving for fuel, which confuses me. last weekend I rebuilt the ignition system, cleaned and set the gap on the plugs, and everything ran well. I have good spark. not sure where to start troubleshooting. I have not messed with the carb setting yet either. Maybe I need to follow Dell's carb setup procedure?? your thoughts and advice are greatly appreciated.

-Ben-
 

Did you get the one piece bowl, screen, shut-off and tap assembly that goes directly into the tank?
 
Front or side distributor?

6v or 12v?

Set the points?

Clean the fuel screens?

" I have good spark"

How did you check for spark?

How's the fuel flow out of the bottom of the carb? (tip # 13)
75 Tips
 
I have tried this before when I was fishing to find the problem,

Get the tractor engine running, if it will, about half throttle, engine warm if possible

Now slowly pull out the choke, if carb, fuel system is proper the engine should start to spudder and slow down,
but if the motor starts to run better faster, then the carb is stopped up,

I had to install an in line metal fuel filter on my tractor to keep the crud that lives in the old tank out of the carb, has worked for many years

You get crud in transfer fuel tanks, the old tank could have a rusty spot inside,
Do you always use a screened fuel funnel when adding gas,
 

It is a front dizzy

12 volt system

I went through and redid the entire ignition system last weekend. cleaned plugs and set gap , wires, cap, rotor, points, set points, new coil and ballast resistor.

I have an inline spark tester, all wires show good spark.

I didn't have time tonight to check fuel flow out the bottom of the carb

what gets me is that with the cobbled together parts that were on it when I bought it everything worked properly. ran well, good fuel flow out the bottom of the carb etc. after putting all new parts in with new, clean screens it ran well for a few minutes and then began surging.
 

how far are u opening the shutoff valve on the new sediment bowl, and how much gas is in your tank?
 
If fuel tank is full of fuel , could your tank vent be stopped up ,
After the tractor runs a short while with no air coming into the tank, the vacuum inside the tank will stop the flow of fuel,

Outside chance this is the problem, but
I have seen this happen before and it will give the best of Saturday mechanics a fit finding the problem,
 
" I have an inline spark tester, all wires show good spark."

The kind with a light or an adjustable gap?

" I didn't have time tonight to check fuel flow out the bottom of the carb"

Get a can & put it under the carb. Remove the bolt in the bottom of the carb; as long as the fuel is turned on, you should see gas flowing out of the carb. It should fill a pint jar in less than 2 minutes. If it?s a dribble, or runs for 5 seconds & stops, or none at all, you have solved half the problem: it?s fuel related. If gas flows well out of the carb & only stops when you turn it off at the sediment bowl, chances are very good it?s not a fuel problem. If it does not have gas coming out of the carb at a steady stream w/ the bolt out for at least 30 seconds, you have a fuel problem. First, remove the gas cap. Your vent could be clogged & it vacuum locked. If that doesn?t work, tap the carb bowl w/ a hammer handle in case the float is sticking closed. (don?t whack it w/ the head of the hammer; you can crack the bowl). If you still don?t see gas flowing, the N has three fuel screens; one in the brass elbow, one in the top of the sediment bowl & one on the stem of the sediment bowl in the gas tank. (see tip # 45) Check the screen in the elbow (see tip # 56) & the screen in the top of the sediment bowl. (don?t worry about the one in the tank) Both probably need to be cleaned. If you have the fuel knob turned on all the way, & 1 gallon or less in the tank, it may be trying to feed off of the reserve inlet which is probably clogged. Only open it 2 full turns. Put at least 2 gallons in the tank. (and do not forget to turn the gas off; see tip # 9)
75 Tips
 
(quoted from post at 06:53:27 01/28/17) " I have an inline spark tester, all wires show good spark."

The kind with a light or an adjustable gap?

" I didn't have time tonight to check fuel flow out the bottom of the carb"

Get a can & put it under the carb. Remove the bolt in the bottom of the carb; as long as the fuel is turned on, you should see gas flowing out of the carb. It should fill a pint jar in less than 2 minutes. If it?s a dribble, or runs for 5 seconds & stops, or none at all, you have solved half the problem: it?s fuel related. If gas flows well out of the carb & only stops when you turn it off at the sediment bowl, chances are very good it?s not a fuel problem. If it does not have gas coming out of the carb at a steady stream w/ the bolt out for at least 30 seconds, you have a fuel problem. First, remove the gas cap. Your vent could be clogged & it vacuum locked. If that doesn?t work, tap the carb bowl w/ a hammer handle in case the float is sticking closed. (don?t whack it w/ the head of the hammer; you can crack the bowl). If you still don?t see gas flowing, the N has three fuel screens; one in the brass elbow, one in the top of the sediment bowl & one on the stem of the sediment bowl in the gas tank. (see tip # 45) Check the screen in the elbow (see tip # 56) & the screen in the top of the sediment bowl. (don?t worry about the one in the tank) Both probably need to be cleaned. If you have the fuel knob turned on all the way, & 1 gallon or less in the tank, it may be trying to feed off of the reserve inlet which is probably clogged. Only open it 2 full turns. Put at least 2 gallons in the tank. (and do not forget to turn the gas off; see tip # 9)
75 Tips

My spark tester is one of the adjustable type.

So I spent some time on the tractor today and found that the fuel flow out the bottom of the carb would fill a pint jar in under 2mins, nice steady flow. While running the tractor I found that if I gave it about 1/4 choke wile it was surging it would smooth out right away. This lead me to believe that the surging was caused by a lean condition. I set the carb up per Dell's instructions that I have seen in many threads here and viola... it runs well and doesn't surge any longer. the main jet was only open 1 turn and the mixture jet was open 3.5-4 turns. While I am pleased with how it is running now I am confused as to why it ran as well as it did with all those cobbled together parts and when I put the proper parts on it began to have trouble. Thanks to everyone who responded to this thread.


-Ben-
 

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