No start 8N PLEASE HELP

John.T

Member
I have a side distributor 8N that won't start. it has new plugs, wires, cap, rotor, points, condenser, coil, intake gasket, known good carb, new gas, good spark on all plugs new ign switch. cylinder compression is 100psi on 4,3,2 and 75 psi on #1. tractor cranks fine but wont fire. Any ideas what im missing?
 
(quoted from post at 22:14:47 08/11/20) John,

I have done it before, but could it be 180
out of time?


I would think it would pop and back fire. The distributor does not look like it was removed. It was brought to me like this.
 
6v or 12v?

You could have a spark issue.


You could have a fuel issue.


Don’t guess. Troubleshoot. See tip # 13 at the link below.


You need to answer 2 questions before you do anything else:


With the bolt in the carb bowl removed and the gas on, will the fuel flow fill a pint jar in less than 2 minutes?


Next, get out your adjustable gap spark checker * , open the gap to 1/4", hook it up, turn the key on and crank the engine. Does the spark jump 1/4"? Post back
with the answers.



* Don't own an adjustable gap spark checker? Buy one! Not a test light! Until then, take an old plug, open the gap 1/4" ground it to the head & look for spark.
It’s not the color of the spark that counts; it’s the distance it jumps.

https://www.autozone.com/test-scan-and-specialty-tools/ignition-tester/oemtools-adjustable-ignition-spark-tester/10257_0_0?
cmpid=PLA:US:EN:AD:NL:1000000:TLS:71700000043798748&gclid=Cj0KCQiAovfvBRCRARIsADEmbRKBdAvAmtFfOvYiYXR7T6NYiW57uyv5-
dEKjVT_h2KogQNUUMsRixYaAlU3EALw_wcB&gclsrc=aw.ds
75 Tips
 
Heed the advice from Ron W and Bruce (VA), don't assume anything. Until you prove otherwise, I'm betting on 180 degrees out of time or the firing order is way off.
 
(quoted from post at 08:32:08 08/12/20) Heed the advice from Ron W and Bruce (VA), don't assume anything. Until you prove otherwise, I'm betting on 180 degrees out of time or the firing order is way off.

Thanks for the input. I've tried the carb on my 2n and it runs perfectly also put my 2n carb on the guys 8n. Nothing. I've used a good spark plug to test spark but not a spark tester. In my experience with automotive ign....if the timing is 180 out the engine will pop and backfire. Is that not the case on a 8n?
 
As was said I would think if it had spark and gas it would "pop" regardless of all other issues. But... not always. If you can
see spark, even weak spark, generally my thoughts go to gas. Are the plugs wet after cranking? Have you confirmed gas actually
getting to carb? You have as many as 3 screen filters and a fuel shut off. Does it pour out of the fuel inlet when disconnected?
Is the bowl full? Is the ignition switch on when you are cranking... not just testing? Ha... i've done that before.

And did it run before or did you change all those things and now it won't run.
 
(quoted from post at 09:52:22 08/12/20) As was said I would think if it had spark and gas it would "pop" regardless of all other issues. But... not always. If you can
see spark, even weak spark, generally my thoughts go to gas. Are the plugs wet after cranking? Have you confirmed gas actually
getting to carb? You have as many as 3 screen filters and a fuel shut off. Does it pour out of the fuel inlet when disconnected?
Is the bowl full? Is the ignition switch on when you are cranking... not just testing? Ha... i've done that before.

And did it run before or did you change all those things and now it won't run.

Good flow of fuel to carb. Actually runs out of carb sometimes...odd thing is the plugs are not wet
 
bring number one cylinder up on compression stoke and see if you are seeing the timing mark. it should be at the 4 degree mark with the piston at tdc, then look to see where the rotor is pointed. Remember the 8n has two sets of timing marks on the flywheel. If the wrong set was used, you would have spark abut not at the correct time. Don't assume that you would have backfire problems, make sure it is right. not hard to do.
 
I've done that on old engines myself. To check that theory,move the spark plug wires to number four where number one is
now,then follow the timing order,1-2-4-3. If it runs,you've solved the problem,if not you've eliminated one possible cause.
As Bruce[Va] stated,diagnose the problem before throwing money at it.
 
The plugs are not supposed to be wet. If they are you flooded it and it will not start no matter how good your spark is.

Fuel running out of the carb throat tells me you've flooded it. Leave the choke alone and use starter fluid.

An old spark plug is useless for testing spark unless you opened the gap to 1/4". Did you?

The cap goes on one way......but the wires can go on 4 different ways. LOOK at the cap. #1 should say 1. Make sure #1 wire goes there to # 1 plug. Then, it's 1-2-
4-3, CCW.
75 Tips
 
(quoted from post at 14:58:18 08/12/20) Good tip iha. I like that.
ctually better than thinking/assuming that #1 marking on cap means anything....distributor can be stabbed such that any one of 4 will be #1. With only 4 trials at installing wires,, you will have covered all possibilities.
 
I will check all these things. The owner said it shut off and never started again after he installed cap and points. The distributor appears to never been out for many years due to the dirt around the base but I will check the timing to make sure. The cap is properly indexed and so is the rotor. Thata why I'm so baffled. Even with starting fluid it wont even pop
 
(quoted from post at 18:41:56 08/12/20)
(quoted from post at 15:25:05 08/12/20) Do you have the little clip under the rotor? easy to lose!

Yes I have good spark at each spark plug
s much as you have cranked on it, you have likely fouled the plugs. Turn the gas off, fresh plugs, no choke, starting fluid spray into intake & try starting. You can see how very narrow the explosive mixture range is in the chart. Flooding kills that.
8JdOPgr.jpg
 
(quoted from post at 13:23:13 08/12/20)
(quoted from post at 14:58:18 08/12/20) Good tip iha. I like that.
ctually better than thinking/assuming that #1 marking on cap means anything....distributor can be stabbed such that any one of 4 will be #1. With only 4 trials at installing wires,, you will have covered all possibilities.

hmm? the front distributor only goes on one way, as the driving slot is off center, and the rotor only goes on the shaft one way.... or are you talking about a side distributor?
 
(quoted from post at 20:29:11 08/12/20)
(quoted from post at 13:23:13 08/12/20)
(quoted from post at 14:58:18 08/12/20) Good tip iha. I like that.
ctually better than thinking/assuming that #1 marking on cap means anything....distributor can be stabbed such that any one of 4 will be #1. With only 4 trials at installing wires,, you will have covered all possibilities.

hmm? the front distributor only goes on one way, as the driving slot is off center, and the rotor only goes on the shaft one way.... or are you talking about a side distributor?
here have you been? First line of his first post! Pot legal there?
 
(quoted from post at 21:06:28 08/12/20) Where have you been? First line of his first post! Pot legal there?

very, but I've not been partaking. :p

i should have read the whole thread again.

I just got mine started for the first time today since I started hacking on stuff a couple weeks ago as detailed on my various threads, so yay for me. its not done yet (need to get the hood back on right, need to replace the air cleaner and muffler and secure them, and need 2 more gallons of coolant mix, and then I need to dial in the carb).
 
John T. You said, "The owner said it shut off and never started again after he installed cap and points." Interesting, did he shut it off and installed new points and cap or did it just quit running? You have spark to all four plugs, out of the head I take it.
 

I will look when I work on it this evening. If the clip was missing would I still have spark at the plugs? What does the clip do
 
(quoted from post at 16:01:47 08/13/20)
I will look when I work on it this evening. If the clip was missing would I still have spark at the plugs? What does the clip do

update. there is no clip under rotor.... i checked dist timing. its correct. pulled out plugs. they were not wet but I decided to install a new set because everything else checked out. put new plugs in. cranked a few times and fired right up. ran well. seemed a little lean. ran rough and shut off. wont start now. pulled plugs. were not flooded/wet. blew them off just in case put back in. no start. pulled plugs and quit for the evening, makes no sense. i know now the engine can run. still baffled. why the no start now. and ideas?
this is exactly what it did for the owner. that's why he put cap rotor points in it and still wouldn't run.
 
(quoted from post at 22:38:16 08/13/20)
(quoted from post at 16:01:47 08/13/20)
I will look when I work on it this evening. If the clip was missing would I still have spark at the plugs? What does the clip do

update. there is no clip under rotor.... i checked dist timing. its correct. pulled out plugs. they were not wet but I decided to install a new set because everything else checked out. put new plugs in. cranked a few times and fired right up. ran well. seemed a little lean. ran rough and shut off. wont start now. pulled plugs. were not flooded/wet. blew them off just in case put back in. no start. pulled plugs and quit for the evening, makes no sense. i know now the engine can run. still baffled. why the no start now. and ideas?
this is exactly what it did for the owner. that's why he put cap rotor points in it and still wouldn't run.
ell, I hate to have to tell anyone the second time & I won't the third, but turn off the gas and try running the SOB on starting fluid. You might learn something. By the way, even though the rotor clip is nice, they will run for decades without one.
 
John.T,You write Fired right up. ran well. seemed a little lean. ran rough and shut off.
Are you sure the carb is not flooding over and causing the plugs to foul/short from gas deposits (it don't take much )
Is the spark weak ,It needs to jump at least 1/4" or more in open air. CHECK THE SPARK!
 
..I checked the spark. It will not jump that far. So I took my spark tester and put it on my 1947 2n that starts and runs well. That tractor wont jump 14" either. I compared the distance each tractor spark will jump. Neither one would jump 14" but both jump equally. The 8N that has the issue has all new ign parts. Soooooooooooo frustrating
 
John.T,The spark should / must jump 1/4" in open air to start and run reliably.Does it have any kind of resister or resisters inline between the ignition switch and the coil? If it does remove them or by pass them as they are not needed.Then check spark,if it is still weak replace the coil,Burn off contaminates on the new plugs with a propane torch and put them back in,give it a shot of starting fluid and start with the gas shut off.See if it will run untill the carb runs dry.
 
I've ran a jumper wire from battery to +terminal of coil to make sure it was a good source of voltage. Plugs NEVER look bad. but I will burn them off just to make sure. The spark not jumping far enough seems to be the issue but not sure what is causing it
 
(quoted from post at 09:47:24 08/14/20) I've ran a jumper wire from battery to +terminal of coil to make sure it was a good source of voltage. Plugs NEVER look bad. but I will burn them off just to make sure. The spark not jumping far enough seems to be the issue but not sure what is causing it
hat sounds all wrong! If 6v as you said, then it is probably a Positive grounded battery. If that is the case, power should be going to Negative coil post and you applying battery power to Positive coil terminal should rather quickly burn the points crispy.
 
John T. Take a real close look at the terminal on the side of the distributor that the coil primary connects to. There is an insulator there to prevent that terminal from shorting to the distributor body. It may be causing all your trouble.
 
(quoted from post at 12:03:37 08/14/20) JMOR, you are assuming the coil primary was wired correctly, polarity wise.
y all the other BS here, I know that I should assume it was wired wrong!
 
Its wired correct. It actually started last evening for min or so. Does everyone agree I need to be able to jump a 14" air gap with the spark?
 
(quoted from post at 12:27:24 08/14/20) Its wired correct. It actually started last evening for min or so. Does everyone agree I need to be able to jump a 14" air gap with the spark?
4" ( fourteen inches will need >500,000 volts, so don't count on it. 1/4" (quarter inch sounds better). :)
 
(quoted from post at 09:41:49 08/14/20)
(quoted from post at 12:27:24 08/14/20) Its wired correct. It actually started last evening for min or so. Does everyone agree I need to be able to jump a 14" air gap with the spark?
4" ( fourteen inches will need >500,000 volts, so don't count on it. 1/4" (quarter inch sounds better). :)

just need to replace that whimpy ignition coil with a nice 6' tall Tesla coil, woooot!

tesla-coil1.jpg
 
(quoted from post at 16:14:41 08/14/20) So at this point no one has any any constructive ideas?
irtually every time I have suggested that you do a particular thing, the next post from you looks like you didn't do it and either repeats the same old saw that, "I've done everything? and am at wits end" or you are off on some other useless tangent such as rotor clip. "It actually started last evening for min or so. That is about the length of time it will run on a carb bowl full of fuel. Starting fluid that you were so slow to follow up on pretty much should have shouted, "It is a fuel problem", but you just kept on chasing spark, right up until now.". Hopefully by now you have removed the plug from the bottom of the carb bowl & measured the time necessary for the flow to fill a pint container. If not do it. How many minutes? And don't tell me, "I did that test and don't remember time, but it was OK or fine!!!!!" not good enough!
 
wow....i sure learned a valuable lesson. very very slow flow through the carb and out the bottom. After removing the fuel bowl housing from the tank and finding the small hole plugged with junk. cleaned and reinstalled. flow tested and recorded one pint in 2.33 mins.
Looking at the "full" sediment bowl gave the false impression of plenty of fuel flow. but after thinking it through what JMOR said it makes sense. the fuel comes off the top. thank you for keeping after me to check the flow. cranked it and shot a bit of starting fluid to it and it fired for just a moment. I've run out of time this evening. I left the plugs out of it as to hopefully dry out any over fuel mess. THANKS AGAIN JMOR!!!! I hope im on the way to making it run!!!
 
(quoted from post at 19:49:44 08/14/20) wow....i sure learned a valuable lesson. very very slow flow through the carb and out the bottom. After removing the fuel bowl housing from the tank and finding the small hole plugged with junk. cleaned and reinstalled. flow tested and recorded one pint in 2.33 mins.
Looking at the "full" sediment bowl gave the false impression of plenty of fuel flow. but after thinking it through what JMOR said it makes sense. the fuel comes off the top. thank you for keeping after me to check the flow. cranked it and shot a bit of starting fluid to it and it fired for just a moment. I've run out of time this evening. I left the plugs out of it as to hopefully dry out any over fuel mess. THANKS AGAIN JMOR!!!! I hope im on the way to making it run!!!
am ,too! :)
 
Just went through that with my 51N. Air leak. Check manifold and connection of carb to manifold.
 

Mission accomplished!!!!! Faulty condenser. Replaced the condenser and now I have plenty of spark. Thanks for all the input!!!!
 

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