1948 8n front dissy, 12v, will not start.

Tractor will not start. Fresh gas and flowing, float in carb fine, cleaned entire carb 2 times. Little dripping out of drain plug when cranking, but not a lot. 90+ compression. Plugs dry. New rotor, condensor, distrib. cap, points, gqpped right. Great wires, nice spark, new coil. All I can figure at this point is timing. I tried to use the t-square method, and it seemes timed right, but I have to say that the cam tangs are not totally square...so it's not all that easy to check using that method.

Tractor ran last sat, after looooong cranking.

" Little dripping out of drain plug when cranking,
but not a lot." Plugs fouled?? Change plugs and see
what happens. Looks like you've replaced everything
else.

(quoted from post at 09:01:19 07/26/11) Tractor will not start. Fresh gas and flowing, float in carb fine, cleaned entire carb 2 times. Little dripping out of drain plug when cranking, but not a lot. 90+ compression. Plugs dry. New rotor, condensor, distrib. cap, points, gqpped right. Great wires, nice spark, new coil. All I can figure at this point is timing. I tried to use the t-square method, and it seemes timed right, but I have to say that the cam tangs are not totally square...so it's not all that easy to check using that method.

Tractor ran last sat, after looooong cranking.

Click to expand...

don't think timing is the place to look, especially since it ran recently with the same timing.

i'm not thinking timing either. there ain't a whole lot of timing adjustment anyway.

dry plugs = no gas to the cyls

soundguy

Have you tried starting fluid?few things i would check,vacumn leak at carb body or manifold,and it is possible on your carb to get a full flow of gas to bottom of carb and not one drop to engine if the right passage is plugged. one other thing,it can jump fire on a plug every lick and not have enough fire to start.one way is to have your ground wire bonded to sheet metal and not engine,another is to have too much resistance in ignition circuit.try jumping the ignition resistor temporarily as your cranking it.MY 48 had this problem,i would jump the resistor,it would fire right off,i would remove the jumper and it would slowly lose rpms until it died and wouldnt start again.I converted it to TRUE 12v ignition and have not had one seconds trouble since.I never checked to see which resistors were bad or where the problem was though ,I simply ripped all the wire out,rewired and converted,I needed the tractor and it was faster to do that than trouble shoot so i didnt bother checking to see if i had a bad resistor,connection ,or what.i had coil and all ready to anyway so i didnt bother ,takes about 10 minutes after youve done a couple,and you have the coil built.

I got good strong spark on all plugs...

If you indeed have good compression & spark, then it's a fuel problem. Timing isn't an issue now. But, given all the issues you've had w/ the distributor, tell us first how you checked for spark.

Then change the plugs.

Then use starting fluid directly in the carb throat, no choke.
50 Tips

you say you have gas dripping,first this is a sign of flooding so your carbs not right REGARDLESS of how many times youve worked on it.BUT and this is what you need to check,you can drip gass out carb while cranking,IF it doesnt fire or has a vacumn leak.heres what happens,it tries to pull gas Up the intake,it pulls through carb,but it doestnt have enough suction to pull it on through manifold.when that happens it runs back down carb and out carb throat.BUT it only does this while cranking,if its dripping gas just setting needle and float is not set right or not any good.there is however another possibility ,rats nest in muffler wont let air flow through engine.have some one crank engine hold hand over tailpipe to check this.it should try to push your hand off each time exhaust opens if it has 90 lbs of compression.our at least you should feel it blowing.are you positive you have choke put together correctly?

No rats nest, use the tractor often...have tried starting fluid also, and, it's not dripping out the carb throat, just thru the little drain, and not much, which isn't a big deal. Float checked, works fine, and, needle/seat, all, checks out, even did a float check with the bottom of the carb off-needle/seat does stop flow.

The one thing I haven't done is change the plugs-despite their having a good spark. I can try that, despite my insistence that if I see a good spark, it's gotta be fine...

(quoted from post at 11:27:36 07/26/11) No rats nest, use the tractor often...have tried starting fluid also, and, it's not dripping out the carb throat, just thru the little drain, and not much, which isn't a big deal. Float checked, works fine, and, needle/seat, all, checks out, even did a float check with the bottom of the carb off-needle/seat does stop flow.

The one thing I haven't done is change the plugs-despite their having a good spark. I can try that, despite my insistence that if I see a good spark, it's gotta be fine...

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hen you install the new plugs, keep the gas turned off & first try to start it on starting fluid only or even propane....without the gasoline.

Tell me it's possible to have strong spark but, yet, it won't run???

(quoted from post at 11:33:40 07/26/11) Tell me it's possible to have strong spark but, yet, it won't run???

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he question becomes the definition of 'strong'. Assuming that you mean all other conditions for running are met, such as fuel/air mix, compression, timing, etc,

The question: " tell us first how you checked for spark."

Your answer: " I see a good spark, it's gotta be fine... "

Erik, you have plenty of folks here trying to help you. Do you not understand the advice, did you not see it, or are you ignoring it?

As others have said:

Change the plugs
Use starting fluid (or propane) no check

The fact that you "see" a "good" spark doesn't mean spit. It's the distance the spark jumps that defines "good spark".

Touchy touchy...geez. What I gotta do, come with hat in hand begging for mercy?

I see dry plugs with a strong spark and it's hard to imagine they're the problem. But, I'm willing to try it...why not.

Have you made sure you have the plug wires in the correct distributor holes?

" Touchy touchy...geez. What I gotta do, come with hat in hand begging for mercy?"

No, not at all. You just need to answer questions for us to assist you & either accept the advice given or tell us why you didn't. This is a cooperative effort.

Regarding the plugs, you can not see the spark-robbing deposits on the plugs left by flooding the engine. Nor can you see inside the combustion chamber.

You do not need to beg for assistance, but a little less attitude might make your quest for help more productive. As you can't/won't explain how you checked for spark, it's apparent that you do not wish to accept my assistance.

Have a nice day.

Not at all, I was just musing how it seemed impossible that what appeared to be a strong spark, wasn't the problem...but, via text on the internet, you thought I was questioning you, on the contrary, I was just exclaiming out loud how it SEEMED impossible...like, my eyes are telling me I have a good bright spark, how can it be?

Getting new plugs tonight...

if your talking about the sintered bronze plug in bttm of carb that is the carb throat.

No, the little tiny 'drain'...

did it start on starting fluid for a second?have you got the air cleaner unhooked?it could be stopped up, if not.IF you know your getting flow through engine( a old packrat will stop one up overnight if he decides to)and your for sure getting good spark,it almost has to be no fuel.this means vacumn leak, passage stopped up in bottom of carb that ALL fuel must pass through,maybe a stuck intake valve blowing fuel back down manifold.A bad ,improperly installed,or cracked venturi in carb will let it suck air.any carb gaskets bad.vacumn leak on throttle shaft (VERY common)etc etc.I personally would start with changing plugs then on to the dist ,make sure you have it in the slot of cam correctly.Make sure firing order is correct, its easy to mess up.then i would remove hose to air breather and eliminate that,then i would take some heavy oil like 90 wt and using a oil can squirt some around gaskets and throttle shaft.sometimes this will help it if it has a vacumn leak to draw enough fuel and helps to diagnose where your problem may be .it is of course possible for one to jump time,but you would likely hear some backfiring either through carb or exhaust.and its unlikely it would start one day and not the next randomly.thats what i do when i'm stumped.Plugs make a big difference on these ,after 60 years the starters dont turn as fast as they should and that dont help anything either.

You dont understand gas fouled plugs.Spark runs up the insulator in thin streams that wont fire the fuel charge.Make sure the spark is jumping the gap.A little starting fluid will start the engine.I have found a few small engines with kerosene in the tank.

Amazing. 4 new plugs and he fired up on the 2nd revolution. Speechless. I've never had this experience, so, now, my problem is solved, but the problem remains-how DO you tell if you need new plugs? That's the part that bugs me.

What I may do is take 1 new one out and watch the spark, then take 1 old one and check it's spark, and then maybe it'll be obvious...From appearance, they look like 2 yr old plugs.

Thanks for the suggestion Bruce and Dell. It's just something I've never really experienced before, in all my years. Still can't believe it...