8n wont start

markman96

New User
1950 ford 8n original 6 volt system sidemount distributor wont start. recently replaced distributer cap and rotor componets and coil. ran fine yesterday then this morning wont even pop. i have spark at the plugs. any ideas
 
yes sir. took the gas line off at the elbo and good flow going throug. took elbo off and cleaned screen still nothing
 
Ah but that is gas to not threw the carb. Pull the drain plug out of the bottom of the carb and make sure you have a good flow there for a few minutes. Catch it to make sure it is not full of water or dirt etc.
Also your spark has to be a good blue/white and jump a 1/4 inch gap or more at all 4 plug wires
 
" recently replaced distributer cap and rotor componets and coil."

Why? Were they defective?

There are two schools of thought when it comes to getting a non-running tractor to start. One way is to just start replacing every part you can get to until it starts or you run out of money. The other way is to take a step-by-step approach to solving the problem, working from most likely to least likely. The trick to fixing these tractors (or trouble shooting any piece of equipment) is to be systematic about it. You need to isolate the problem step by step and work from most likely to least likely.

You do not know if you have a spark or fuel problem.

It takes three things for an engine to run: spark at the right time, compression, & fuel in the right mixture. For the moment, forget about compression & concentrate on narrowing the problem down to spark or fuel.

There are three very important tools you always need to have in your N tool box: a 3 inch piece of wire w/ alligator clips on each end, an old spark plug w/ the gap opened to at least 3/16” ( ¼” is better) and a 7/16 box end wrench. (see tip # 50 at the link below) And, you really do need a working ammeter on the tractor; it is a very important diagnostic tool. With these tools, you can quickly narrow down most N problems to spark or fuel.
First, check for fuel. 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. Let it run for at least 30 seconds. 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. So, next, turn the key on, crank the engine & look at the ammeter. What is the needle doing? Does it show a constant discharge, no movement at all, or does it move back & forth slightly? Next, get the old plug, ground it to a rust & paint free spot on the engine, turn the key on & crank the engine. If the spark jumps the 3/16” gap, you probably don’t have a spark problem. If it won’t jump the 3/16” gap, you have a spark problem. If the ammeter needle shows a constant discharge, or doesn’t move at all, that also tells you that you have a spark problem. Jump the ignition switch w/ your jumper wire & see what happens. If it runs, you found the problem. If it doesn’t have spark after you jump the ignition switch, post back for more info on further troubleshooting. (and do not forget to turn the ignition switch off; see tip # 38)

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. Check the screen in the elbow & 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)

There are ways to check for spark & fuel that work & ways that don't. For example, having gas to the carb is nice, but having it past the float is what counts! That’s why removing the 7/16” bolt in the bottom of the carb is the way to check for fuel. And, same thing w/ spark at the plugs. Some folks think that checking for spark means pulling a plug wire off & looking for one. Well, it's the distance the spark jumps at the plug that gives you the info you want. It takes about 17kv to jump a 3/16" gap & 22kv to jump ¼” in the open air. Remember, it’s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air creates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running. A store bought plug checker will work better than an old plug because it won’t shock the snot out of you like an old plug might!
75 Tips
 
Yes and catch it so you can look for water and dirt in it which will cause problems
 
yes sorry i was called into work. now i have checked flow though carb and it has good flow through. and the gas does not appear to be dirty. so this means it is a spark issue most likley?
 
no they wernet defective. we had to install a radiator on the tractor and figured minus well do a tune up on the old tractor. then when assembled it all ran fine. and now this. keep in mind it is about 10 degrees here
 
Maybe spark but it can also be other problems. This time of year an engine does not like to start well unless every thing is just right. Yes check your spark and make sure it jumps a 1/4 inch gap or more. You also might try cleaning out the air cleaner and make sure it is not full of mud and ice. Also maybe pull the plugs and make sure they are not wet with gas which fouls them
 
will do thanks for the advice. like i said we had it runing just last night. plowing even! this morning wont even fire a single cylinder
 
Ya snow makes water which can short of the spark inside the distributor that is why we say check spark then carb
 
While not the best way to check for a distributor cap that is cracked but works well is hold one hand on the cap and spin it over trying to start it. If you jump 10 feet then you know you have cracked distributor cap
 
so i have good spark at all 4 cylinders. how ever the number 4 cylinder(farthest from radiator) the spark is good bvut it seems to be half as frequent.
 
Did you replace the points when you did the tune up?? If yes what did you set the gap at?? If I remember right you have the side mount distributor which means you should have the points gaped at 0.025. Spark that is hit and miss can be gap set wrong or distributor shaft bushing getting bad etc. Check point gap at all 4 lobes o the distributor and make sure they are the same. Oh and by the way did you buy the good parts or the cheap might be ok China parts
 
i noticed the distributer shaft didnt have any side to side play how ever it did have a little bit of tortion play. and i actualy did only check at one lobe so i will check all right now. but i have good spark at all plugs. jjust a bit unfrequent at the fourth.so shouldent i have been getting some ignition at least? cuase i am still getting none
 
Pull the carb to air cleaner tube off and make sure you do not have a carb full of gas. If you do then it is flooded and you need to clean the plugs by heating them up with a lighter etc. If no gas then try starting it and hold your hand over the carb air intake. It may even try to start. When real cold out I have to do that on my 841 at times
 
well my carb is not flooded. and i put my had over the carvb and it had good sucking but still nothing was firing
 
What plugs do you have in it?? You might try pulling the plugs and make sure they are not fouled out and also make sure each has a blue/white park at the plug them self. If you do not have auto lite 437s you should look into getting a set of them
 
as of now we have champion h12 plugs in the tractor. also when we bought it it had 2 anti foulers on the 2 and 4 cylinders. is that meant to be? or just some ingenuity on the previous owners part
 
Those anti foulers are on just to cover up oil burning problems. I would buy a set of auto lite 437 plugs they are by far better then the chaps and with this newer crap gas seem to work better. By the way if it would help you can send me an e-mail and I'll give you my home number. I have found some times it help a person to be able to talk one on one and have had many call me over the years
 
we have a set of autolite 437 laying around i wiull try those right now. thanks for the helpi wil let you know what i find
 
First, charge the battery.

You need a strong battery to:

1. Close the solenoid

2. Spin the starter

3. Engage the bendix

4. Provide voltage to the coil.

As the battery gets weaker, the first thing to fail is your spark. If the battery is almost totally dead, all you will hear is the solenoid clicking.

The more current you use to spin the starter, the less you have for the ignition.

Next, replace the plugs. If you flooded it, they're fouled & it will be it next to impossible to start. You don't need to toss them; heat the tips for a few seconds w/ a propane torch to burn off the invisible spark-robbing deposits from today's additive filled gasoline........or wash them in lacquer thinner.



While each N has its own starting sequence, none of them will start well by just yanking out the choke rod & holding it out for 5 or 10 seconds while the engine cranks. This is a gravity fuel system on a low compression engine; it is easily flooded by too much choke.

Try this:

Remove the breather hose.

Get a can of starting fluid.

Key on, gas on 2 full turns, clutch in, 3/4 throttle, press the starter button. Let it crank for at least 3 - 4 seconds before you spray the starting fluid in the carb throat.

Post back w/ results.
 
apologies for the late reply as i have been plowing. and after trying the new 437s and playing with the distributer cap i was able tyo get her running. thanks all for help
 
with new plugs and a cxharged battery i got it to start up. also by plkaying with the distributer. and holding in the clutch helped. thanks all
 

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