Need some ignition help please

My 62 f1434 has been converted to 12v with 1 wire alt and external ballast resistor. I've had to rebuild engine and marked all wires before removal.

I do not have spark!!

I've been through these troubleshooting instructions twice, all is good, everything checks out fine... I cannot get spark from coil wire if I hold it a bit off ground while cranking. "Points Not Firing Coil" Step 8.

http://mightymo.org/Proj_No_Spark.html

I've checked for significant voltage drops but seem to have full battV where it should be. I've checked for points grounding out to dist plate. I have all new ignition parts and tried another new condenser but no luck. I made a second ground strap from engine to frame.

With the - dist wire connected to coil I get resistance between point arm and dist housing. Is this normal? I checked the dist wire to be sure it wasn't grounding to housing at the insulator an all is good. Is this resistance coming from the coil?

Any ideas??? I've spent a couple hours digging around using the Search function.

 

Okaaayy, took plug wire and put into coil output. Spark plug grounded to head bolt. Jumper wire from point screw touched to ground.

Ign off = no spark
Ign on = spark

 

So that is all good. Are your points clean? I mean filed then white-paper-pulled-between-them clean. Even "all new" points can be contaminated, from the factory.

Seems like they are not grounding for some reason.

 

I made sure to have continuity between point point mounting plate and dist housing. I'll file them a bit tomorrow...thanks

 

Are they opening and closing properly?

 

Yes, I made sure they were completely closing.Gapped at 20 thou.... LOL, I'm telling ya...I know in the end it will be something simple but I might be bald from scratchin my head.

What do you think the minimum voltage is required to fire the ignition? My batt is showing 12.35 volts now.

 

If you open and close the points manually, you should be able to get a spark from a grounded sparkplug - just as you did with the jumper. Which also proved you have adequate voltage.

12.35V is plenty. Don't over-think this yet.

 

So if there is no spark then the points are grounding elsewhere correct?

I hope to have a bit of barn time tonight....fingers crossed. I'll double check that.

So something I thought of today was that I dont remember if I was using a 6v coil or 12v before the engine rebuild. Pretty sure I would have changed that as well when I did the conversion 25 years ago. Naturally I pitched the old coil. What I have now is a 12v coil with external resisitor. I got this part right...right?

My dad said it ran when he parked it 10 years ago so I don't think anyone had their hands in the wiring during that time.

Thanks for the help everyone!!!

 

"So if there is no spark then the points are grounding elsewhere correct?"

Depends. The spark is generated by the alternation of a ground/no ground cycle.
The spark occurs at the instant when the energized coil is de-energized.
The coil is energized (hot) as long as the points are closed and the coil circuit thus has a ground leg.

When the points open, the circuit is interrupted, and the coil "fires" a spark.

Since it worked with a jumper, it seems your issue is located somewhere between the coil and the distributor-to-block ground.

SO... Question - when you got a good spark with the jumper and ignition on, was the distributor and point system wiring from the coil still hooked up too, or did you disable that connection?

If it was still still in the circuit, it would seem that the points were open at the time, or are not providing a ground when closed as they should, or the circuit has an "open" somewhere and not carrying voltage to ground.
If it was not hooked up, then it suggests that part of the circuit is somehow grounding continuously, even when the points open.

Man - it would be quicker to actually fix this than to write it!

 

PeteL, taking the time to type that is much appreciated. What I'm really thankful for is the "filing the points" suggestion. Made a few passes and whaalaaa!!!!!!!!!!!!!!! finally have spark. Now if I can get fuel tomorrow...then engine break in will be achieved!!!!!

Whoooohooo!!!!

 

Okaayyy!!!

Always start with the simple stuff... and the "new" stuff.

 

Update: after many,many attempts at adjusting the float level (not even close to what the rebuild notes said) its running really nice. Stumbles a bit off idle but I think a little ignition timing will fix that.

Turned out the knucklehead that assembled my engine didn't bother to get the camshaft gear/oil pump properly aligned with the dist. My rotor was pointed at #4 cylinder. Anyway I'll have a oddball firing order for a bit but at least its finally running. Only took me all day...LOL...on to the brakes...weehaaa!!

 

There are different variants of float needle and valve, and they require different float settings. Some generic carb kits do not have the rough-service Jeep-type needle.

 

What setting did you wind up using for the float? PeteL is correct in that if you use a solid brass spring loaded needle the setting is one measurement and if you use the VITON tip needle it's another. By the way, if the stumble is just off idle your problem is probably the metering rod setting.

 

Welp, I had a solid needle which matched my original. When I replaced it the adjustments were way off from the rebuild kit specs. I set it to the specs suggested and the float dropped so far that the needle snagged the float and stuck wide open. I didn't measure my final adjustment but I took some float drop out( enough to keep it off the bottom of the bowl about 3/4) and bent the center tab enough to allow a bit better than a 1/4 inch of needle drop. I put a slight L into the center tab to help get a straight shot at pushing the needle up.

I suppose I'll wait to see how it drives... I might need to do more adjusting.

This Jeep will barely ever see the road other than plowing out the neighbors.

 

From your description, you may have fixed it. You may also have set it to flood severely and cause an engine fire. Details my young padowan. Really do need to know what model YF you are running because settings are slightly different from one to another. A loose rule of thumb is to have the float at least level with the cover when inverted (minimum 9/32" measured without the gasket in place) with a maximum float drop of 1 1/4" when upright. Keep a fire extinguisher handy. Don't guess. Too critical.

 

The float valve orifice size also is a factor. Jeep applications used a smaller opening than other YF equipped vehicles, to reduce the fuel pressure on the float.

You need to know exactly what parts you are using, and research the correct specs for them.

http://www.jeepsurreygala.com/?page_id=979
http://CJ3B.info/Tech/Carter.html
http://CJ3B.info/Tech/Carburetor.html
http://www.carbkitsource.com/carbs/tech/Carter/Y-index.html

 

My engine has no timing marks at all (unless the flywheel is marked, but there is no way to tell without dropping the trany/tc and pulling the clutch assembly and the flywheel.)

Made my own timing marks by determining TDC on number one and setting the mark 5 degrees before that for firing.

Timing light shows the mark to be right if timed from number 4 instead of number on. Doesn't really matter much as long as it will time up and run from one of them. You just have to determine which one by moving the timing light connection from one plug wire to the next until you get a reading at idle. Which is what I did, then fine tuned it with a vacuum gauge.