1948 8N hard to start

[billbill1]

I read some before posting, a friend of mine brought me his 8N to work on. At first, there was no spark, removed the points (new) filed them some and reinstalled. I ran a compression test on all four cylinders and each one has 120 lbs. of compression. It has a brand new coil, has been converted to 12 volt. At first, on the distributor side of the coil, I had constant 12 volt, now it goes on and off as it passes each lobe. It was rebuilt several years ago and the engine is completely spotless. Machine is in very good condition, very clean. My buddy says he could always get it to start by pulling it but has always had problems starting from the starter. He loaned the tractor to a friend of his and it hasn't ran since. I told him to bring it by and I would try and get it going for him. He also told me that it has always burnt the points since he has had it. He is willing to buy a pointless ignition or anything it needs to get it right. I looked online at the pointless ignition and found them for around $85, are they better than the regular point system? I haven't checked the timing yet. I pulled the carb (also new) and it had a small amount of water in the bottom, i cleaned that up and the carb to manifold gasket was shot so I made a new one. He replaced the sediment bowl, it leaks and will need replaced again, I can't get it to stop leaking at the bowl and the rubber gasket looks OK. It spins over fine but doesn't try to fire. I know lots of you guys know all about these tractors and I'm wondering what to do next. Don't want to start throwing money at it until I get it firing at least. Thanks in advance for your help. Each plug is firing but the spark seems weak to me but I know nothing about these little machines.

 

[billbill1]

Something else, it has the distributor to the front on the right side. I gapped the points to 15.

 

[Sgt Maj]

Bill- before you spend on electronic ignition, I recommend you figure out the root cause of the problem. Adding the new parts may not solve the problem, and may add new ones...(some guys love the electronic ignition, and they work fine, but I don't think it is necessary to convert).
It sounds like you previously burned through points, but now you have weak spark. And, you have 12V at the coil when points closed and maybe half or less when points open?
Make sure when tractor is not running you turn the key OFF-- not doing so will burn points quickly. Sometimes even the coil burns out too.
Check the pigtail at the bottom of the coil to make sure it extends far enough to make good contact with the brass screw (concave head) in the distributor. Check the insulator under the screw is not cracked.
Since you have the 12V conversion, check the resistance across the coil is about 2.5 ohms.
Check that the condenser wire isn't grounded to the side of distributor.
Make sure you have both cap and coil gaskets in place. The coil should be tight on the cap, make sure the bail is tight and there is no movement.
There should also be no side-to-side movement of the distributor shaft, otherwise the bushings will need to be replaced. and your points.
You could also re-check the gap, is it still .015?

For the gas leak, make sure the bowl is centered on the gasket, and the screw under the bowl is good and tight. Sounds like you may just need a new gasket though.

 

[Oldtractorfixer]

You noted 12 volt conversion. Most times you need a resister on the 12 volt side of the coil to drop to 6 volts when running or you will burn the points. Sounds like this has been going on for a long time as the owner has to pull it to start. With everything else you have checked I would for sure be checking the timing. I really like pointless conversion, do it once and forget about points forever but you need to find the real problem first. Some of these have a screen in the inlet fitting of the carb. Check you are getting fuel by removing the drain plug from the bottom of the carb. With the fuel on you should get a steady stream of fuel out of the drain hole. If your spark is weak go back to the points and put in new ones even though you filed them they still may not be making good contact. Make sure the ground side of the points has a good ground to the distributor body. Also do your trouble shooting with the air inlet disconnected from the carb. That way you know when it tries to flood. Keep us posted someone here will have the answer.

 

[Soundguy]

if it's buring points, you are doing something wrong.

first.

is this really a front mount with square coil that sets on the distribuitor?

are you using a good napa/echlin point set? not tisco crap?

are you using the oem 3 terminal dash resistor AND a new 2.5 ohm 12v square coil?

filing points ruins them.. you take the micro hard coating off them.

if they are buring, primary current is too high, gap is wrong ( usually too close ), or they are oil contaminated, or they are not striking square.

.015 for front mounts.

also.. plug gap is .025 excessive plug gap will lead to points arcing.

post back

 

[boggen]

gave up on on the old glass bowl screen and filter and gasket on the 1954 allis chalmers ca tractor. and my memory way back when... the glass bowls also been a pain to deal with. i went and got a inline plastic fuel filter with barb ends, and some hose that came as a kit. and never looked back at the stinking glass bowl.

if you looked at the stupid bowl wrong it would leak, if you ran tractor for so many hours it would leak from vibration, if you barely caught the screen on something it would stretch and be junk, the gasket was more prone to damage than anything from cork to rubber, to other gasket materials. if you got just a bit of gas, oil, grease, or hands just plain wet from say wiping sweat off yourself, you have issue trying to even tighten the nut on them (butterfly or small gear looking nut), the glass bowl gas filters to me are complete junk.

i also installed an inline shut off valve. with the inline plastic filter. the old allis chalmers did not have a shut off valve for the gas if i remember correctly and if it did, maybe it was old and worn out and reason for new shut off valve.

 

[billbill1]

Chris, the distributor is mounted front but it has a tube style coil. I haven't been around this tractor, just trying to get it going for a friend. Doesn't say anything on the points as far as a brand name. I didn't mess with it yesterday, going to dive back in to it today, raining here so I have time. He wants me to make this right and I have no timeline, just working on it when I can. Are you a fan of pointless ignition? Several choices online. I will keep you posted and I'm sure I will be back several times. Thanks

 

[billbill1]

OK guys, I got it running. I found out is was a side mount distributor, the guy that owns it also had a front mount at one point and explained the difference. I took the advice you all gave me and it worked. Found several things out of adjustment. Knowing side mount distributor, I adjusted the point to .025, the plugs to .025. I checked the timing and it was close. The air jet on the carb was only turned out 1/2 turn and the gas needle was off as well. After I got it to idle, I was able to fine tune the jets to where it ran the best. It started back up fine after I got everything set but want to check it this morning to do a cold start. Thanks you so much for all of the tips and pointers. This is such a great group and so very helpful. If I still have problems, I will be back.

 

[billbill1]

I was sure I had this going, started fine yesterday morning. Friend was going to come and get it today. Tried starting this morning and no fire again. Don't have time to work on it today but thought I would post back, still something not right.

 

[billbill1]

OK, I checked this out closer, it has 12.64 volts to the primary side of the coil. It has the resistor but it doesn't seem to be doing anything or it wouldn't have 12.64 volts, would it? It also has 12.64 volts to the points that drops to zero when the points close. The coil is 6 volt non resistor type, shouldn't it have a 12 coil as well? I read through the past posts and saw that Soundguy recommended a NAPA coil-non resistor type. I'm going to look back and see what he said it was and get one. I have thought the coil was a problem and think this might be part of the problem. It also has the oil bath air cleaner and it had lots of crude in it, I cleaned it up but is there something better that I could add. Thanks for any help you can give.