My new 40 won't start...

[Nate89]

Here is a pic of the carb:

And one of the truck!

 

[Nate89]

Did you check for spark on the plug wires?

I pulled a plug and rested it on the neg terminal of the batt and cranked the car. I was getting spark, but not the blue spark I expected. It was more of a orange color.

 

[emac]

Pull coil wire off of dizzy and see if it has a strong spark. Also check for corrosion on the rotor and cap contact areas. I assume battery is strong and it is cranking over good. Once you do that and feel comfy you are getting good spark, spray some starting fluid in the carb and see if it fires and runs a second. If it does, move to carb and fuel supply.

 

[Nate89]

Pull coil wire off of dizzy and see if it has a strong spark. Also check for corrosion on the rotor and cap contact areas. I assume battery is strong and it is cranking over good. Once you do that and feel comfy you are getting good spark, spray some starting fluid in the carb and see if it fires and runs a second. If it does, move to carb and fuel supply.

That's the thing, I'm getting a spark at the plugs, but it looks weak. I completely disconnected the coil from the truck, then I hooked up the pos terminal to the batt. I placed the high voltage output wire near a ground, then I connect the neg terminal to the neg side of the batt. From what I've read I should be seeing a nice big spark from the output wire, but all I get is some little blue sparks from the neg terminal (no arcing).

Here is the starter wiring, can anyone confirm this is correct? The pos cable has been replaced. I'm not sure what that yellow wire is for?? I just have it hooked up to the pos terminal.

 

[emac]

I THINK the yellow wire may plug on the oil sensor. You can see the round terminal it may connect to. Its the thing between the two blue pipes in the picture. But the other loose wire may go to the oil sensor. Hard to tell and I am just going from memory.

If you think spark is weak at the plugs, then check spark at coil wire. If it is strong, then check dizzy/point gap, corrosion, etc. Simple thing would be the points/condensor are bad. Not sure you replaced them. Point gap tends to close with wear.

Also, starting fluid will let you know if is enough spark to fire. Is the dizzy tight where it wont rotate?

 

[Nate89]

I THINK the yellow wire may plug on the oil sensor. You can see the round terminal it may connect to. Its the thing between the two blue pipes in the picture. But the other loose wire may go to the oil sensor. Hard to tell and I am just going from memory.

If you think spark is weak at the plugs, then check spark at coil wire. If it is strong, then check dizzy/point gap, corrosion, etc. Simple thing would be the points/condensor are bad. Not sure you replaced them. Point gap tends to close with wear.

Also, starting fluid will let you know if is enough spark to fire. Is the dizzy tight where it wont rotate?

You were right about the yellow wire being for the oil press sensor. I've narrowed the problem down to being a spark issue. I rebuilt the carb yesterday and it works great now. Fuel level is right in the middle and I get fuel through the accelerator pump.

I have cleaned the points and adjusted the dizzy. I'm wondering if the coil is wired correctly/getting enough voltage. How can I go about testing the coil without a multimeter?

 

[edwjmcgrath]

First, buy a cheap multimeter. $20. You can't debug wiring and electrical stuff without one and if you own a 40, you're going to be debugging wiring...
Second, is the new coil you bought meant to be used with an external resistor or is it meant to be fed 12v? If it is meant to be fed 12v then that can cause weak spark.
Third, are you sure that the points are opening and closing and are wide enough apart? That can cause weak spark.
When you cleaned the points, did they look like they needed it? New points cost under $10. I wouldn't spend 5 seconds cleaning old points.
Third, double check your wiring. Turn the ignition to "on" and measure the voltage on the resistor terminal that is NOT connected to coil positive. It should be 12v. Now check the voltage on the other terminal. If the points are open, that should also be 12v. If they are open then have someone tick the engine over until you can see them close. Now measure the voltage on the other terminal (or the coil positive). That should be about half of the full battery voltage. Roughly. Now measure the voltage on the coil negative, that should read zero. If not, the points are resistive and need replacing.

How did you adjust the dizzy if it won't start?

 

[splitshot]

Could be something as simple as a battery cable (been there). They might look ok on the outside...
Corrosion inside will sap any juice to the ignition while the starter is pulling.

 

[sggoat]

That's the thing, I'm getting a spark at the plugs, but it looks weak. I completely disconnected the coil from the truck, then I hooked up the pos terminal to the batt. I placed the high voltage output wire near a ground, then I connect the neg terminal to the neg side of the batt. From what I've read I should be seeing a nice big spark from the output wire, but all I get is some little blue sparks from the neg terminal (no arcing).

Here is the starter wiring, can anyone confirm this is correct? The pos cable has been replaced. I'm not sure what that yellow wire is for?? I just have it hooked up to the pos terminal.

With the coil out of the circuit, I doubt if you would get any but a small, battery induced spark.(BTW-the yellow wire w/black stripe goes to the oil pressure sender)
For the coil checks(and you do need a VOM for this)--
and the wiring for the GR starter--looks like yours is correct--

 

[honk]

Nate, you said:

"Funny you mention the solenoid. I don't hear the click with the key, but when i was testing the coil I touched a jumper wire from the coil to the battery and i heard a click. I tried it again and put my hand on the carb and I could feel the solenoid click. So it does work, but I forgot which wire i jumped since this was a few days ago."

From this it doesn't seem clear that the idle stop solenoid is doing it's thing when it's supposed to do it. You've established that it does work but it's got to work with voltage supplied it when the ignition key is on - any time that the engine is running it is energized and allows fuel to flow. When the key is switched off the solenoid is also switched off, immediately stopping the fuel flow to the idle circuits in the carb. If it is never energized the truck will never run.

So if you did not hear that solenoid when the key was switched on it is likely that the solenoid is incorrectly wired.

Mine is wired directly from the coil positive terminal. I'm not sure it's the OEM way but it is a working way. If it is the OEM way then from your description of the wiring leading into your coil terminals the one to that solenoid is not present.

Put a testlight to your coil positive and verify that it switches on with the key, and switches off with the key. If it does then a simple jumper wire from that same coil terminal to the solenoid on the carb should result it a noticeable click as you turn the key on and off. You've got to have that thing click when you turn on the key (!)

If you then do hear that click turn the key further to the start position and listen to your engine start right up. Smile, and honk the horn.

 

[Captn Conch]

I don't know if anybody mentioned it but I can't tell if your coil wire is new or old... if it's old it could be a good area for weak spark, unless you know it's history, it may look good but be a real weak point through internal deterioration or separation.

 

[mags]

Shout out to Emac for the Spark Plug test, and Nate for the thread! My Old 40 wouldn't start one morning after I just rebuilt the carb and put a new exhaust manifold gasket in. I started thinking carb, but I had also messed with the distributor some. Thankfully I didnt get too far down the carb road before reading this thread! Pulled #1 Sparkplug and held it against the block while my son cranked it. No spark. Coil was old as crap and I had just purchased a Pertronix coil in prep for a points to Pertronix ignitor swap. Put the new coil in, had the wife crank it and got spark! Reinstalled and now I am warming her up to reset the timing as I swapped out the points in this process (still waiting on my Ignitor conversion kit to show up tomorrow). Anyways the point is Mud is awesome Thanks again Emac and Nate!