8n Ford Won't Start

8NJimmy

New User
My 8n won't start!!! I've done all of the normal suggestions to get it to run.. new plugs and wires, points etc., new sediment bowl and shut off, new carb, timed, spark jumping 1/4" gap, 105lbs compression all across, fuel thru carb.. all it does is pop out the carb and won't start.. What am I missing???
 
More info needed for us to be able to help you help your self. Front or side mount distributor?? 6 or 12 volts??
If front mount did you set the points at 0.015?? Have you made sure that the points open to that 0.015 on all lobes of the distributor shaft?? Had one I worked on not long ago and found the points would only open to 0.012 and it would not run and found the distributor shaft bushings where bad so points did not open like they should have.
If it is a side mount are the point set to 0.025?? Do you have a good blue/white spark at ALL 4 plug wires?? Do you maybe have the wires on the cap incorrectly as in out of firing order?
 
It is a 51-52 8n ford.. Side mount dist.. I just checked the distributor lobes and all open the points at .025".. I installed a new coil.. Pos lead to dist.. 6 volt positive ground.. I checked the spark with a plug set at 1/4" and got a good spark snap on all 4 wires... The firing order is 1243 and have double checked at the dist.. Jim
 
If I where you I would set a 12 volt battery in it and see if it fires up. If it does good chance the starter is pulling to many amps from the ignition system. Doing that for a short period of time will not hurt a thing. Ya you do not want to run it for an hour with a 12 volt battery but for 15 or so minutes it will not hurt it
 
I mic'd across the lobes in the dist. and got 0.775" and 0.776".. The shaft doesn't appear to have any slack in it and the centrifugal advance is lose and working ok.. I'll give the 12v battery a try... tks..jim
 
Ya some times the 12 volt battery trick is enough to change the engine attitude so it will then run. Seen where doing that one time then going back to the 6 volt and all is well till it gets hard to start again
 
Ok... Stuck in a 12 volt battery.. All it does is turn over faster.. It continues to pop out of the carb... I pulled the plugs and none of them are wet??? I squirted some marvel oil in each cylinder in hopes it might improve the compression... (105lbs across all 4) I'm not sure it is vaporizing the gas into the intake manifold... I would think that over choking would either flood the carb or at least send raw gas to the cylinders... I squirted some start fluid into the intake manifold with no results.... I'm getting more and more confused...
 
With the air cleaner tube off and 12 volt battery try putting your hand over the intake of the carb. You should get a good suction on your hand plus gas on your hand. Shoot it may even try to start doing that. Or you may have the plug wires on 180 out which will cause them to pop but not start
 
If it's popping through the carb, make sure you put the plug wires on, in the right order, and if you removed the distributor, make sure it's not 180 degrees off.
 
I've performed that test before.. did it again... Good suction, gas in my hand... won't start... Double checked the timing order.. #1 cylinder is next to radiator... The rotation is CCW.. #1 cylinder on the cap is pointing towards #1 cylinder... Firing order 1243 CCW...
 
Pops through the carb isnt good. better check firing order, someone may have moved 2 wires around. just saying. I got a 8N. I'm going to guess and say its 1-3-4-2 (common for many 4 cylinders) and rotor goes counterclockwise. (maybe clockwise) Ive never confirmed this. So remove the cap and turn it over to check direction.
If still no fix,confirm #1 wire is on right spot of cap. (in case someone removed all wires)
Remove sparkplug #1, put finger on the hole, turn over engine, by hand if possible, when you hear or feel the cylinder push air, thats TDC, stop when mark on front crank pully is up. see small notch. Align notch with timing plate for Zero degrees. look for where your rotor is, should be pointing to #1 on Cap. Then next in order around the rotor should be 3 then 4 then 2. Maybe someone monkeyed with it. crossed your wires. Im going to guess you crossed #2 and #3 wires when you did your plugs.
So if firing order is ok, Well, the other diagnosis would be one of your intake valves are burnt out or sticking open. My tractor had acorns in the intake manifold from some small animal living in there.
I suppose that stuff could get into the block where the valve is and obstruct the seating on the intake and cause that carb pops, but, these valves are in the block and thats downwards, so gravity could permit debris to enter this combustion chamber. Suction pulls in crap too. The overhead valve engines worry about water/weather entering the muffler. Goes right into the chambers and ruins exhaust valves. Ive seen this.
But Ford flatheads are different.

If still no start, do compression check. If no compression in any cylinder, on these flat head engines, remove head and observe valves in block. clean them with gas or diesel and wire brush, turn over engine watch if gas leaks by valves when their closed. you may have burned or rotten valves. Todays gas destroys yesterdays valves. No lead in fuel. I always use high octane gas. burns cooler. ok. feel free to let us know how you made out. good luck. Greg
 
TDC is piston at Top Dead Center. You can use a screwdriver inserted into the hole and feel the piston up too. just be sure the exhaust valve isnt open in that cylinder, you would be 180 degress off. Thats why i say, wait for your finger to feel the air pushing out then stop. If no air pushes out ever, you got a bad valve, and possibly more bad valves.
Some people use a lead additive to avoid burning valves out. I use high octane. It helps.
I'm trusting there is gas getting to the plugs and you have spark.
 
About the only ones that used the 1,3,4,2 was Farmall. Ford A/C MH MM and many others used 1,2,4,3. And if you get the 2 firing orders mixed up the engine will not run well if at all
 
popping out the carb is firing while the intake valve is open, that can happen for several reasons, first your firing order is off related to where the dist rotor is pointing when number 1 cylinder is at tdc, hand crank the engine until your sure your at tdc, then pull the cap and see where the rotor is pointing, wire the dist from that position, it may be off, next its rare but carbon holding the intake valve slightly open will cause it to fire thru the carb, but even then it should run on the rest of the cylinders, change plugs and see if it helps
 
someone before me stabbed the dist. about 4 teeth off... I reset the dist. and it started right up... I learned a lesson on this one... Thanks again for all your helpful suggestions.... Jim
 

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