Weak spark at points

[Jim.ME]

Consistently fires only number 2 cylinder?? You bought a replacement engine, did this distributor come with it? Maybe there is something oddball about that distributor. Not sure what that would be that would allow it to fire at one distributor cap terminal and not the others. Does this use the rotor clip I hear repeatedly mentioned in Ford circles?
Bottom line is have you seen this distributor run an engine?

Good question on the clip.

Does the shaft have a clip the rotor slides on over? Is the rotor tight on the shaft?

 

[560Dennis]

Electronic ignition is fine for above 5000 rpm . Or dual points

 

[TheBartman47]

Another thing to check is whether the distributor lobes are worn down so much that it isn't fully opening the points.

 

[DERM]

Have you checked the insulator in the distributor where the points attach to the wire from the coil ? it could be grounding out

 

[Ray,IN]

We are well down the Rabit Hole. Since we are at "PLAN F" level- check the/any dist cap center Carbon Button. Can jam up, or become Glazed over. When in doubt- bend up the rotor tab up with your thumb-nail. Did you wiggle rotor/ shaft side to side to check for grossly trashed bushings? These are forgiving, but a bit of brass each 1/2 century needs to get swapped sometimes. Lastly, old machines can sometimes wind up with rotors and caps that do not quite match up, even if they look OK. Decades for "LOOKS Good enough" / "what the parts store has.." types of fixes. Hope you get her running.

Exactly my point. I had bought a tune-up kit made in China for my old MF135 and the "new" points didn't fit exactly, then I found out the insulation for the part that fits over the post in the dist was missing/incomplete, so the new points didn't work.
The movable point is the + and the stationary point is the -, if the movable point is not completely insulated it grounds enough the points can have a very weak spark at times.

 

[Ericp351]

Simple suggestion- If not already done- Pull all plugs. Re attach wires- charge bat. Lean plugs against block. Spin engine, ign. on. Look for 4 blue sparks. IF NOT- move any "good"-#2?- wire and plug over/ swap. See if troubles move or not. Good luck. Post script- I say highly unlikely dist cam lobe wore out! Remember- when in doubt--- a narrow gap is a reliable gap. Can go down to 10 thou for testing.

 

[used red MN]

Remember- when in doubt--- a narrow gap is a reliable gap. Can go down to 10 thou for testing.

That would seem to be an unsubstantiated claim. You can set the gap at 30 if you want as long as the rubbing block comes off of the cam in the flat between the lobes the points return spring will apply the same amount of force to close them and establish contact regardless of what you set the gap. Set the gap to the proper spec to test the system properly.

 

[13fx]

You originally posted you were using a timing light to test for spark. That is testing on the high side of the coil, to do that you need to connect it to the coil wire or a plug wire. I suggested using a test light on the primary side of the coil, the small terminal the wire that goes into the distributor body, then the points, hooks to. No where until you posted this did you say you were testing as I described. They are two different methods, which did you actually do?

What is the voltage at the battery terminal of the starter solenoid at rest? What is the voltage at the battery terminal of the starter solenoid When the starter is cranking the engine over? Too much voltage drop during cranking can affect the ignition function.

U apologize, I misread what you posted. I never would have thought about putting the timing light on the low side.

Consistently fires only number 2 cylinder?? You bought a replacement engine, did this distributor come with it? Maybe there is something oddball about that distributor. Not sure what that would be that would allow it to fire at one distributor cap terminal and not the others. Does this use the rotor clip I hear repeatedly mentioned in Ford circles?
Bottom line is have you seen this distributor run an engine?

So I finally got good spark. It was the points after all. I still can't wrap my head around why I was getting spark on #2 and non of the others I'd the points were bad. As for your question about that little metal clip for the rotor yes I use it. I hate having fixed the issue without understanding what was wrong with the part. But at least I'm getting spark so now the rest is cake.

 

[Ericp351]

That would seem to be an unsubstantiated claim. You can set the gap at 30 if you want as long as the rubbing block comes off of the cam in the flat between the lobes the points return spring will apply the same amount of force to close them and establish contact regardless of what you set the gap. Set the gap to the proper spec to test the system properly.

To clarify- I meant PLUG Gap, I may have been unclear. Agree that points should be set to about spec. I go with a thou or 2 wide, as Point-block wear is not linear, that is, rapid wear first interval, then lower wear per interval until wore out. I have measured on my higher performance cars. A narrow plug gap will cover a problem, like weak or hot coil, lean mixture, bad plug, poor wires, et cetera. In short-for me- a narrow gap AT The Plugs- will get ya started, or home. PS> I scrolled up. seams the gentleman fixed it . All good!

 

[Jim.ME]

U apologize, I misread what you posted. I never would have thought about putting the timing light on the low side.

TEST LIGHT, NOT TIMING LIGHT!!



You say it was the points after all. What did you do to fix it?

 

[used red MN]

So I finally got good spark. It was the points after all. I still can't wrap my head around why I was getting spark on #2 and non of the others I'd the points were bad. As for your question about that little metal clip for the rotor yes I use it. I hate having fixed the issue without understanding what was wrong with the part. But at least I'm getting spark so now the rest is cake.

Apparently working through to the point of starting it is still in the works? Did the points basically look brand new or were brand new? If so these guys likely nailed it as my guess.

I agree, I once bought a new set of points, they didn't work. Where they fit over the mounting peg had no insulation, so they were constantly grounded.

Have you checked the insulator in the distributor where the points attach to the wire from the coil ? it could be grounding out

Did you ever try reading the “ignition on” voltage on the coil terminal with the lead from the distributor with both the points closed and open? This would have probably told you a lot and possibly given a clue to your problem. The test light on that circuit while cranking would be the down and dirty version of this test. Inconsistent spark from the secondary requires verifying the function of the primary system first, in a trust worthy Kettering troubleshooting tree.

 

[used red MN]

To clarify- I meant PLUG Gap, I may have been unclear. Agree that points should be set to about spec. I go with a thou or 2 wide, as Point-block wear is not linear, that is, rapid wear first interval, then lower wear per interval until wore out. I have measured on my higher performance cars. A narrow plug gap will cover a problem, like weak or hot coil, lean mixture, bad plug, poor wires, et cetera. In short-for me- a narrow gap AT The Plugs- will get ya started, or home.

Sorry I gotcha, not sure how I went from spark plugs in your discussion to points.

 

[kencombs]

Yes, and that's exactly what I have been doing. I will get the light to flash once every 2-3 full crank rotations. When I open the points manually I get a spark at the points every time but it looks really weak.

om

U apologize, I misread what you posted. I never would have thought about putting the timing light on the low side.

So I finally got good spark. It was the points after all. I still can't wrap my head around why I was getting spark on #2 and non of the others I'd the points were bad. As for your question about that little metal clip for the rotor yes I use it. I hate having fixed the issue without understanding what was wrong with the part. But at least I'm getting spark so now the rest is cake.

Post 17. I tried. Guess I wasn't clear. When one sees a 'weak spark' when the points break, there isn't sufficient current flowing to make a big spark. Bad connection, wiring or points.

 

[used red MN]

Post 17. I tried. Guess I wasn't clear. When one sees a 'weak spark' when the points break, there isn't sufficient current flowing to make a big spark. Bad connection, wiring or points.

I think your reply was clear. Sometimes recommendations get stepped over here when troubleshooting tips are coming at the OP fast and furious. I hope you agree that the priority is that the member can solve his problem and move on towards enjoying his machine.

 

[Jim.ME]

I apologize for not understanding you were using a test light, not a timing light, from the way I read your posts.

As for intermittent spark, a couple things might be the ground for the points may have been bad or contact surfaces not always making contact. I had a set of points that didn't move on the arm pivot freely and would hang up at times and not close. Checking them and cleaning them checking for no spark wiggled them enough to free them and they went back to working until the next time they caught.

I may have missed it but how did you fix it? Install new points?

 

[13fx]

U apologize, I misread what you posted. I never would have thought about putting the timing light on the low side.

So I finally got good spark. It was the points after all. I still can't wrap my head around why I was getting spark on #2 and non of the others I'd the points were bad. As for your question about that little metal clip for the rotor yes I use it. I hate having fixed the issue without understanding what was wrong with the part. But at least I'm getting spark so now the rest is cake.

Holy cow, I can't believe I didn't catch that typo. I am sorry that probably came off very offensive that should have been I apologize, not you apologize.

 

[13fx]

Went to test start an engine today and am getting intermittent spark spark. Wanted to see what was happening so I put the timing light on the coil wire and was seeing spark once every 2-3 rotations of the crank. Pulled the cap off and started checking spark at the points. The spark there is weak. I took the condensor off and the spark got weaker. I have checked resistant on the line coming into the coil and it is fine. I checked the coil and it tested ok. I replaced the coil with one off a running tractor and nothing changed. The battery reads 6.8v the coil on the low side reads 6.4 when open, the high side reads 6.2-6.3 when closed. I tested the points for resistance and they tested fine when closed. Tried a new rotor, I've tested the plug wires for resistance and they test fine. The plugs have all been pulled and cleaned. Resistance from the coil to the points tests good. I'm not very good with electrical work and have run out of ideas.

So it seems that I owe a couple of apologies here. First I didn't catch a fat fingered typo that was supposed to say I apologize, but ended up saying u apologize. The second thing I have to apologize for is I misread a reply asking if I was using a test light or a timing light. I don't know how I didn't understand the question or if I just skipped over that, I thought that you were talking about the the testing process not the testing tool. Lastly I had fixed the problem by replacing the points altogether. I still don't understand why they were bad and why I would get consistent spark on #2 cylinder but I have saved the points for a rainy day to mess with and try to understand just what went wrong with them.

 

[Jim.ME]

So it seems that I owe a couple of apologies here. First I didn't catch a fat fingered typo that was supposed to say I apologize, but ended up saying u apologize. The second thing I have to apologize for is I misread a reply asking if I was using a test light or a timing light. I don't know how I didn't understand the question or if I just skipped over that, I thought that you were talking about the the testing process not the testing tool. Lastly I had fixed the problem by replacing the points altogether. I still don't understand why they were bad and why I would get consistent spark on #2 cylinder but I have saved the points for a rainy day to mess with and try to understand just what went wrong with them.

no problem, glad you got it running.

 

[wore out]

So it seems that I owe a couple of apologies here. First I didn't catch a fat fingered typo that was supposed to say I apologize, but ended up saying u apologize. The second thing I have to apologize for is I misread a reply asking if I was using a test light or a timing light. I don't know how I didn't understand the question or if I just skipped over that, I thought that you were talking about the the testing process not the testing tool. Lastly I had fixed the problem by replacing the points altogether. I still don't understand why they were bad and why I would get consistent spark on #2 cylinder but I have saved the points for a rainy day to mess with and try to understand just what went wrong with them.

Thanks for posting back!

I'm not surprised (post #14) that the breaker points were "bad".

 

[John T]

When I get back to my laptop I will post my ignition troubleshooting procedure to help ypu

Often the cause of your problem is dirty corroded carboned up or oiled oxidized or mis gapped ignition points

John T