Ford 8N Starting Problem

[equeen]

I'm back again with the 52 Ford 8N issue. A "mechanic" has the tractor but he's had no better luck than I have. It started and ran well - once for about 15 minutes for him (as it has done for me), then hasn't started again.

Fire to plugs - he says fine blue fire.
Compression around 100 on each cyl.
Removed exhaust pipe, then manifold to check for obstruction - none.
Valves needed some adjustment - done. They go up and down.
Carb rebuilt - and tried pouring bit of gas in each cyl. No ignition.

Checked distr timing against marks on flywheel and watched rotor turn.

What are we missing? Apparently something that allows ignition at times and no ignition at times - mostly no ignition.

Thanks for any and all ideas.
I'm tired of "trying" this and that. And I'm tired of hearing about the "mechanic" "trying" this and that. Next "trying" plan is to remove head and "look at valves". Why????
 

[don t-9n180179]

When it dies, check for spark.
If no spark, jumper around the ignition switch and try to start.
If it works, you know what part to buy(grin).

HTH...good luck...don t. .....
 

[old]

Check to be sure the points open to the same gap or very close on all 4 lobes. Next hot wire it. If it runs when hot wired you have problems from the coil back if it still does not run double check spark at the coil wire and then all 4 plug wires. The color of the spark is worthless if it will not jump a 1/4 inch gap or more at all 5 places
 

[Royse]

I don't remember what you've done up to now, but an intermittent problem is always the worst.
At the moment it quits, do you still have spark? Still have fuel?
Does the distributor shaft wobble side to side at all?
Have you checked the insulator where the wire goes into the distributor to the points?
I don't see any need to pull the head and "look at the valves".
Bruce(VA) has a great step-by-step posted out here numerous times.
If he doesn't chime in, you may want to search the archives for it.
Best of luck!
 

[Bruce (VA)]

You need another "mechanic."

" Next "trying" plan is to remove head and "look at valves""

That should be the reason. If you had a valve problem, it would have shown up in the compression check.

Go get the tractor & fix it yourself.

Next time it stops, check quickly for fuel then spark. When I say quickly, I mean get off the seat, grab the tools & do it right then. Do not wait a minute or two. 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.


Do you have battery voltage across the points when they are open? Verify the gap on the points at .025. Then, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. (I always spray my feeler guage blade off w/ contact cleaner.) Make sure you have voltage across the points, as in past the insulator on the side of the distributor. That is a very common failure point on sidemounts, along w/ the attached copper strip. It's hard to find a short there because it is usually an intermittent . So 'wiggle' the insulator & the copper strip a bit when you are doing your checking. If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all. If you just replaced the rotor & lost spark, put the old one back in. Insure that the rotor fits firmly on the shaft & that the little clip is there. Make sure the distributor cap is not cracked & doesn't have carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. In fact, replace it temporarily w/ a plug wire. Next, remove the secondary coil wire from the center of the distributor cap, turn the key on & crank the engine while holding the end of the wire 1/4" from a rust & paint free spot on the engine. You should see & hear a nice blue/white spark. If not, you have a bad coil or condenser. Just put the old condenser back in to eliminate that as a possibility.



Post back w/ results; I'll be interested in what the problem was.
50 Tips

 

[Royse]

That would be it, thanks Bruce!
Glad to see you online after the storm.
I hope you weathered well!
 

[Dell (WA)]

equeen.........you write......."and tried pouring bit of gas in each cyl".......might as well whipped out the ol'whizzer and peeeeee into the engine. Liquid gasoline does NOT ignite!!! Must be a vapor. That is what yer carby does, create a burnable vapor for the sparkies to sparkle.

The 5-nipple roundcan ignition coil is semi-bulletproof. HOWSOMEVERS; the side plastic feedthru can short out and you will never make sparkies. And when you change points (0.025") ALWAYS polish the INVISIBLE corrosion from between the points. Me? I use a clean $1-bill clamped between the points and pull. Iff'n yer really cheap, tear a strip from HEAVY brown paper grocery sack and use that.

Leave yer frickin' head on, its is NOT yer problem. Ford compression specs: 90psi min, dry; new rebuilt engine is about 125psi. From yer 15-min runtime description, change yer weaksister ignition switch. ($10, cheap) ........Dell, yer self-appointed sparkie-meister
 

[NoNewParts]

all great advice
#1 on a side-mount is the wire pass thru on the distributor.
sooner or later, they all go bad.
a rust 'bridge' there makes it intermittent and tough to find.
also, as said, ignition switches made today are always suspect,
even the toggle switches I use are 50% bad today out of the box
.....or soon after.
Since it has had many hands working on it,
static time it by the book, and lock it down and leave it until
you get it running.(make sure you use the right timing
marks, there are 2)
In the field with no tools, I take the cap and dust shield
off, turn the key on and crank it over
and LOOK at it.
bright point spark on all lobes even when
wiggling thru connector?
ok, no problem here, on to the next.........

edit: just wanted to add, that when you are following Bruce's
good methodical testing write-ups.
Never skip over a part just because it's new.
test everything.
chasing a random miss, on a Ford, and a JD recently,
putting a meter on the new ignition switches on both
1 key, 1 toggle, showed my meter dancing all over the place.
both junk
 

[Bill Bull]

Oh stop !!!

equeen.........you write......."and tried pouring bit of gas in each cyl".......might as well whipped out the ol'whizzer and peeeeee into the engine. Liquid gasoline does NOT ignite!!! Must be a vapor. That is what yer carby does, create a burnable vapor for the sparkies to sparkl


EVERYONE at one time or another has fired a engine by "Priming" the engine by putting "A little" gas in the cylinders !

Put your books away!
 

[Bruce (VA)]

Yea, all is fine here in VA. Thank goodness I'm not further north. What a mess.
 

[Bruce (VA)]

" EVERYONE at one time or another ......"

Which of course makes it a perfectly acceptable action.

It also washes the cylinder walls & fouls the plugs.

Starting fluid doesn't.
 

[William Fissell]

This same symptom happened to my 640. Drove me nuts.

As it turned out for me, the points had been modified to do away with the copper strip and the plastic square and screw, and the wire from coil to points was run through the hole in the distributor directly to the points, as has been described here at length. Well, on mine, the wire was getting flogged by the advance weights, which ripped off the insulation and shorted the coil to ground at inappropriate times. Sometimes a bright blue spark, sometimes no spark. Sometimes start, sometimes start and quit.

Good luck, just passing on a 'gotcha' that drove me nuts for a few weeks.

Bill
 

[Kenster]

[equeen]

Okay, it doesn't matter what has been done before by whom. I have the tractor back here and I'm starting as if nothing has been done/checked. I will NOT be taking the head off to "look at the valves".

Compression is approx 100 (meaning 98-103 or so) on each cyl - cold, dry.

Battery at 6.2v.

Clip jumper from hot at starter to clip on other side of tractor for use as needed when needed. (Points are open on distr.)

Two different coils tested, not attached to distr: 6.2v negative post in, 6.2v from tower, 6.2v positive post out.

(Please confirm that the coil for a positive ground tractor should receive battery power on the coil's negative post and should send power to the side post on distr from the positive coil post..................)

NO voltage reading from either coil when wired positive post to side post on distr.

Points and condenser checked. New points and condenser checked. No voltage reading on side post of distr. (Sounds like a solid short in distr now???)

Points set and checked at each of 4 lobes of distr and steady at .025.

New copper tab and insulator previously installed on side of distr. However I am concerned regarding the paper thin (maybe paper) insulator inside the distributor between the copper tab and inside wall of distributor????
 

[Dell (WA)]

equeen........compression is "O.K.", NOT chur problem.

You ask........"Two different coils tested, not attached to distr: 6.2v negative post in, 6.2v from tower, 6.2v positive post out".......this is NORMAL for roundcan coils. Ittza LAW, Kerchoff's Law. Yer coil is what is classed as "auto-transformer" meaning ALL the turns are connected together. HOWSOMEVERS iff'n you "ohm'ed" between 2-terminals you'd read about 2-3 ohms for the primary (battery) turns and about 1700-ohms fer the high sparkie term (center term)

You complain......."No voltage reading on side post of distr. (Sounds like a solid short in distr now???)" Iff'n yer points are closed, you will NOT read volts at the feed-thru. Ittza LAW. Kerchoff's Law. HOWSOMEVERS, the plastic feed-thru can also SHORT and you will also read NO VOLTS. Points must be OPEN (visually inspect) for volts at the feed-thru. ........Dell, yer self-appointed sparkie-meister