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Cub WILL NOT FIRE...Tried Everything!

R

RTR

Well-known Member
Ok, so this guy's Cub I am working on trying to get wired correctly will not run. He told me he couldn't get it to crank after installing new points, etc. That is one reason I was to check the wiring besides checking to see if alternator charged. We have installed a NEW set of points, and I wired the ignition correctly. We are getting fire EVERYWHERE and a good spark at that; but there is no fire coming from distributor cap to spark plugs. We have tried a couple other distributor caps, a couple other rotor buttons, and another set of New wires; and still NO FIRE.

We are scratching our heads!!!! Please HELP. THANKS .
 
"We are getting fire EVERYWHERE"

HOW can you say "we are getting fire EVERYWHERE and then go on to say there's no spark at the plugs???

First of all, is there a good HOT spark at the coil's high-tension terminal? is the coil wire in good condition?
 

I was trying to point out that we were getting it everywhere but the plugs. Yes, there is a great spark at the coil's high tension wire. We changed to another set of plugs and still nothing.
 
(quoted from post at 00:42:34 12/16/10)
I was trying to point out that we were getting it everywhere but the plugs. Yes, there is a great spark at the coil's high tension wire. We changed to another set of plugs and still nothing.
Click to expand...

EDIT: I mean to say "we changed to another set of PLUG WIRES". Apologize for the error.
 
fire at points and none at plugs ---dead condensor. even if you just installed it - change it .
 
Turn the engine to top dead center on the timing pointer. Or by a finger in the #1 plug hole [on compression]. Take the distributor cap off & see where the rotor is pointing inside the cap. It should be pointing to the #1 terminal on the cap. If you have trouble with this procedure, take a pencil & make a mark on the distributor case where #1 plug wire connection is. Sounds like your rotor isn't lining up with the dist. cap contacts when the points are opening [firing]. Incorrect timing is the issue here.
 
"Incorrect timing is the issue here. "

Yeah, but how does that happen with an IH DISTRIBUTOR.... wrong rotor, perhaps?

Or does he have a mag that's been converted with an external coil to battery ignition???
 
sorry, didn't fulley read your post. missed part about new rotor button. agree with post conserning timing being off. good luck, d.coleman
 
Brownie, not a challenge and just for my own education, he says he has NO fire from cap to plugs. Timing would be firing but just at the wrong moment...right? Absolutely no spark coming out of the distributor would have to be a component within the distributor along the path the electricity follows. I have to go with Cowman. Run continuity until you find the break in the circuit. Help me out here if I am wrong.
 
RTR and ALFarmallBoy,

Welcome to the forum. I first noticed your posts in the last couple weeks.
From what you have posted you have 30 some IH tractors and have been buying and selling tractors for some time. From this post you seem to be having a very basic and elementary problem.

Someone told me once, if you are having a problem that doesn't make sense it's probably something you forgot in the first plase, so back up and start from the beginning.

For and engine to run you need 4(four) things:
1. Air
2. Fuel
3. Compression
4. Fire (at the appropriate time)

Start at number one and work to number four.
I might add, make sure the wires are on the cap to the correct plug.

Dell
 
Incorrect timing will not cause no fire at the plugs. If you are out of time the plugs will still fire just not at the right time. I'd vote for bad condenser.
 
Run my Troubleshooting Procedure may help, but if the coils HV output tower is firing good but no fire to ANY OF THE PLUG WIRES SOUNDS LIKE A CAP OR ROTOR PROBLEM or wrong or off index rotor or wrong cap etc. Ive seen rotors that are shorted out ID CHECK THAT !!!!!!!!!!!!!!!!!

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T
John Ts troubleshooting
 
Actually he has told us what's wrong. If he has
spark at the coil and not at the plugs. Either of
about 3 things. The rotor is shorted. The rotor is
not turning. Or the rotor is indexed wrong so it's
not pointing to the tower at point of fire. All he
has to do is fix it.
 
(quoted from post at 03:03:24 12/16/10) Actually he has told us what's wrong. If he has
spark at the coil and not at the plugs. Either of
about 3 things. The rotor is shorted. The rotor is
not turning. Or the rotor is indexed wrong so it's
not pointing to the tower at point of fire. All he
has to do is fix it.
Click to expand...


Thank you all for the quick and helpful responses thusfar. I GREATLY appreciate everyone of you!!

First of all, we have tried just about everything you all have mentioned (as far as trying other parts). The best we could get was a VERY TINY BIT of spark out of the plug wires at the plugs. When the guy wanted us to work on it, he came to the house with the distributor with him (oh no!!), so there is NO TELLING if the timing is correct or not. Who knows, he could have taken the governor off too; BUT we should still be getting spark!! We have not tried another condensor yet, but have a couple extra used ones we can try.

If you guys can give me until say Friday evening or Saturday; we should be able to get back on it. I actually just got my 1st JOB, and will be starting tomorrow. I am working as an Environmental Engineer with the State Dept., so we will see how that goes!! haha.

What we are going to do is:

1st install and properly torque a new head gasket (long story)
2nd while the head is off, we are gonna check timing
3rd after all of that is done and bolted back down, we will go from there.

For some reason....the owner takes the head off (I didn't ask why), and HE USES THE OLD HEAD GASKET BACK ON THE TRACTOR!!!! (shaking my head), I am about 30 years younger than he, and even my inexperienced self knows better than that. Anyways...despite the head leaking all the way around it, we figured we'd go ahead and try to see why there was NO SPARK at all. I will keep you all updated with what we find, and thank you soooo much for your help and precious time. There really aint no tellin' what he's done to the tractor. HAHA.
 
You either have a bad rotor, bad cap or the rotor isn't turning. I would pull No1 sparkplug near the radiator and bring that piston to TDC on the compression stroke. Then see where the rotor is pointing. If it's not pointing to the No1 plug tower on your cap you need to pull the mag or distributor and rotate the rotor so is pointing there and then reinstall it. Make sure your wires are on the cap in this firing order. Hal

2-1
4-3 as the rotor turns CW.
 
If you have a mag, I would guess that the gears that drive the rotor are timed wrong. If you have a dist, are you sure you have the right points in it. If you have the 6 cyl points installed in a 4 cyl dist it will be out of time too.
 
I am assuming this has a J-4 Magneto, you cant just take the old cap out the cap gear and points out and install new ones. all that has to be re-timed when installing. go to www.brillman.com this is a company out of virginia, they specialize in everthing electrical for the older tractors. I had a cub that was basically doing the same thing. They were more than happy to help troubleshoot the problem and I didnt even have to purchase anything from them. Give them a call or check the website and I think they will be able to help you out. Good Luck
 
Hi! Dave. yes, I'm probably wrong on this one also. He said he had spark from the coil to dist. center contact. So, the spark is lost between the center terminal & the individual plug wire connectors on the cap. About 2 ways to loose spark at this point---grounding out & no continuity through cap &/ or rotor.
 
Could you please enlighten me as to how a set of 6cyl. points would cause it to be out of time, since there are still only 4 lobes on the dist. cam. From what I can see, based on some part numbers, they are the same points for some 6 and 4 cylinders, but those are newer than his Cub.
 
If he brought the distributor over to you, and making sure it was timed properly wasn't the FIRST thing you did when you reinstalled it, that's where you went wrong.

Without being 100% sure that it's in time all other effort is wasted.

That's still not going to fix your no-spark problem.

Have you taken the distributor cap off and cranked the engine to see if the rotor is turning?
 
I don't have a book here in the house but there are different numbers for the points. The ground point is different. the 4 cyl is square & the 6 is offset. & I think the movable point arm is a different length. If you see them side by side, the difference is obvious.
 
Hmmm. Interesting. I see different numbers for different years(but these arent IH numbers, they are some numbers in a book my parts guy gave me.) On most IH dist. systems it shows the same part number for the time frames, and it says 4 or 6 cyl. engines with notations for Cubs, and diesel distributors (MD - 450) showing different number for each. I was just wondering if perhaps this manufacturer has possibly designed a set of points to work in all of them for the time frames it shows. I think Ill do a liitle more digging!
 
I don't have them right here to compare but I think the rubbing block is different and will cause it to break(open the points) at a different time.
 
I don't have them right here to compare but I think the rubbing block is different and will cause it to break(open the points) at a different time.
 

FYI: I've actually purchased replacement points through NAPA, O'Reilly's, etc. and have had the rubbing block to be installed BACKWARDS. Its happened more than 1 time too. All I did was take a screwdriver and spin it around though.

We should be able to get back on the little Cub tomorrow, and I'll let you guys know what we find. THANKS SO MUCH FOR ALL OF YOUR TIME AND HELP!
 
(quoted from post at 10:10:45 12/18/10)
FYI: I've actually purchased replacement points through NAPA, O'Reilly's, etc. and have had the rubbing block to be installed BACKWARDS. Its happened more than 1 time too. All I did was take a screwdriver and spin it around though.

We should be able to get back on the little Cub tomorrow, and I'll let you guys know what we find. THANKS SO MUCH FOR ALL OF YOUR TIME AND HELP!
Click to expand...

UPDATE:

We got the new head gasket on and torqued down to 45 ft-lbs. While it was off we found that the timing was 180 degrees off, and fixed that. Once everything was back together again, we tried to start the tractor. Still having the same problem. No fire through the spark plug wires. It is getting lost somewhere between the rotor button shaft on the distributor and the plug wires themself. The coil is firing excellent. We also checked the rotor to see if it was turning, and yes it is. We have tried new wires, new distributor cap, and a new rotor. Still no luck. What is next?? New distributor??
 
RTR, a couple of quick questions before I respond further. When you say new wires, cap, and rotor. Does that mean brand new or just different, ie. new to the tractor.

Also, the wires are they copper core? has the coil to dist cap wire been replaced? Is the #1 post on the cap at 1:00/2:00 o'clock when installed?

also, try running a plug wire from the coil directly to #1 spark plug (bypassing the dist cap and rotor), and see if you get any fire. then do the same for #2, #3, and #4. That will tell you if the plug wires are good/bad.
 


Tom,

The parts I said we tried were both new and some were just different. We've used both types. THe original wires weren't copper core, but we tried a set that were. We have used both types of plug wires on the Coil to Dist. Cap routing, and both types produce a nice blue spark when grounded to head bolt. I don't know about the 1 o'clock or 2 o'clock position; but I will check tomorrow. I am thinking it was at 1 o'clock when they checked it.
 
Thin king back to the last note I threw onto the other thread, as far as checking out the plug. I think I stopped at checking the spark from the end of the plug wire. If the plugs are then suspect the last, of course, would be to check the plug with it out. You'll need a place to rest the plug so that it's gorunded, then have a look at he aprk with the wire connected. Sometimes I've had difficulty finding a good ground and have been known to clamp the plug into one end of jumper cable, with the other end connected to the grounded terminal on the battery.

Only other thought I'm havin, is what do you have your points set at? Mags are .013", battery ignitions are .020.
 
(quoted from post at 15:11:41 12/18/10)
(quoted from post at 10:10:45 12/18/10)
FYI: I've actually purchased replacement points through NAPA, O'Reilly's, etc. and have had the rubbing block to be installed BACKWARDS. Its happened more than 1 time too. All I did was take a screwdriver and spin it around though.

We should be able to get back on the little Cub tomorrow, and I'll let you guys know what we find. THANKS SO MUCH FOR ALL OF YOUR TIME AND HELP!
Click to expand...

UPDATE:

We got the new head gasket on and torqued down to 45 ft-lbs. While it was off we found that the timing was 180 degrees off, and fixed that. Once everything was back together again, we tried to start the tractor. Still having the same problem. No fire through the spark plug wires. It is getting lost somewhere between the rotor button shaft on the distributor and the plug wires themself. The coil is firing excellent. We also checked the rotor to see if it was turning, and yes it is. We have tried new wires, new distributor cap, and a new rotor. Still no luck. What is next?? New distributor??
Click to expand...
Are you sure that the spring end of the points is not grounding out to the distributor? Happened to me once when the little plastic insulator broke.
 
(quoted from post at 20:05:29 12/19/10)
(quoted from post at 15:11:41 12/18/10)
(quoted from post at 10:10:45 12/18/10)
FYI: I've actually purchased replacement points through NAPA, O'Reilly's, etc. and have had the rubbing block to be installed BACKWARDS. Its happened more than 1 time too. All I did was take a screwdriver and spin it around though.

We should be able to get back on the little Cub tomorrow, and I'll let you guys know what we find. THANKS SO MUCH FOR ALL OF YOUR TIME AND HELP!
Click to expand...

UPDATE:

We got the new head gasket on and torqued down to 45 ft-lbs. While it was off we found that the timing was 180 degrees off, and fixed that. Once everything was back together again, we tried to start the tractor. Still having the same problem. No fire through the spark plug wires. It is getting lost somewhere between the rotor button shaft on the distributor and the plug wires themself. The coil is firing excellent. We also checked the rotor to see if it was turning, and yes it is. We have tried new wires, new distributor cap, and a new rotor. Still no luck. What is next?? New distributor??
Click to expand...
Are you sure that the spring end of the points is not grounding out to the distributor? Happened to me once when the little plastic insulator broke.
Click to expand...

Ahhhhhh!!!! We double checked the timing and still nothing!!!! It must be losing fire through the distributor shaft. The PO could have had the governor off and moved the gears. What do you think??
 
I don't think that's gonna be your answer. Being severely out of time (as in misaligned governor gear) would not reduce the strength of the spark, it would simply introduce the spark at a time that is less than optimum for proper running.
 
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