Still No Spark 1950 8N 12v conversion.

[Soundguy]

ditto what jj said.

you can do a quick go / no go thumb test on each cyl to see if the valves are opening and closing.

post back

soundguy

 

[J_J]

What is your timing ? Is it TDC or so many degrees before TDC. Timing will prevent you starting and work against you by firing sooner then it should.

I used to set timing and check firing on different engines by using an AM radio. When the plug fires, you will hear a pop on the radio. If the timing should be TDC, then you can perhaps see the cyl at TDC or put a dowle rod in the cyl and when you turn the engine over slowly, if the timing is set correctly, when the cyl is TDC, the points will open and the plug will fire.

You do know the purpose of firing off the plug before TDC, advance timing, and that is to spark the mixture and allow the mixture to ignite and start burning before TDC which will give the most power out of the gas mixture when the cyl is at the top of the stroke. .

I actually had one engine that retarded the spark which was in a turbocharged Corvair.

 

[2LateIWon]

This is what boggles my mind. It was working perfect and supper strong. I was brush hogging a field (I only had about 5 acres left ) and I noticed it start to loose power. By the end of the day it could hardly cut in first gear full throttle. It sounded like it was missing. So I loaded it up took it home put new points and condenser in and haven't got spark since then. (I put new spark plugs on right before I mowed this property) Until just the other day thanks to JJ and Soundguy. So last night I tried changing back to the old cap and rotor to see if that changed but sill no go. So put new cap rotor back on. I took the spark plug out of #4 put my thumb on it and it blew it off. I poured a little gas in the hole and still nothing. So I've never messed with the timing. Theoretically after I got spark it should have started right back up. Now I'm completely dumbfounded. So agin thanks guys for hanging in there with me.

 

[jinman]

Ok Firing order is correct. and gap is good...... after about 5-10 seconds trying to start nothing after the 3rd or 4th try I get a back fire. I don't get it.

Pull your coil wire out of the top of your dist cap and hold it near ground while turning over the engine. If it arcs regularly, then everything is good up to and including the points. If not, then the points and before are still a problem. If the spark from the coil wire is good, put it back into the distributor and pull the No.1 plug wire and look for a spark as the engine turns over. It should spark at 1/4 the rate of the coil wire. If there is no spark, then your cap is not seating properly or the rotor button is not seated properly. Make sure the inside of the dist cap is clean and dry and it is seated all the way down. If you have a points cover under the rotor button, make sure it also is seated properly. It doesn't take much out of position of the dist rotor or cap to cause big problems.

 

[JC-jetro]

Additionally you can buy HF Inline Ignition Spark Checker to figure out if you get spark up to the plugs. It is very convenient to use and needs no tools at all.

JC,

Inline Ignition Spark Checker

 

[2LateIWon]

Good point about the speed of spark from the coil to the #1 cyl.

Thanks I actually bought the spark plug light/tester from HF just for this LOL ( I needed to buy one anyways) It works great

 

[JC-jetro]

Good point about the speed of spark from the coil to the #1 cyl.

Thanks I actually bought the spark plug light/tester from HF just for this LOL ( I needed to buy one anyways) It works great

I had an unreliable feed back from my Jeep's Crank Position Sensor that was totally random and a holy pain in you know where. The tester really helped me to diagnose. Changing the CPS was another lovely experience

JC,

 

[V1Rotate]

Do you think there might be two problems going on at the same time? By that I mean it seems that you have the ignition problem solved (maybe) but what about a fuel problem? Do you think the initial power loss might have been caused by bad fuel or dirt in the carburetor and now that fuel problem might be causing it to not start?

Just taking some shots in the dark.

 

[2LateIWon]

Do you think there might be two problems going on at the same time? By that I mean it seems that you have the ignition problem solved (maybe) but what about a fuel problem? Do you think the initial power loss might have been caused by bad fuel or dirt in the carburetor and now that fuel problem might be causing it to not start?

Just taking some shots in the dark.

I wouldn't doubt that at all. I'll pull the plugs again and actually put fuel down in each cyl and see what I get.

 

[Soundguy]

I had an unreliable feed back from my Jeep's Crank Position Sensor that was totally random and a holy pain in you know where. The tester really helped me to diagnose. Changing the CPS was another lovely experience

JC,

not an apples to apples comparison.. but did make me think about it.. a ford powerstroke diesel has a cps sensor that will up and quit and leave you on the roadside..... the cps ( cam sensor ) on a ford diesel is easy to change.. cut the wheel hard tot he side and a lil tab with 1-2 bolts hold it in.. unplug and plug new one it. like a 20$ part.. yet.. it will elave you walking on the roadside.. most powerstroke owners I know carry one in their glove box just for this reason..

soundguy

 

[jinman]

Most likely you have a drain plug on the bottom of your carb. If you can remove that, it will drain the float chamber and may clear any trash or water that could settle there. With the plug out, open the petcock from your fuel tank to allow fuel to drain through the carb. This will ensure that you are getting fuel out all the way to the carb and that the float valve is opening properly. After draining, replace the plug and wait a few seconds for the float chamber to fill up, then retry starting. I would not try to get the engine to start by pouring raw fuel into the spark plug holes. There's too much of a chance that you will fill the cylinder and get hydraulic lock on the engine. I would use starting fluid in the air intake to see if that gets any ignition response.

 

[Soundguy]

yep.. and if you do the start fluid deal.. slip the air tube off the carb to keep the start fluid from getting filterd by the oil.

soundguy

 

[JC-jetro]

not an apples to apples comparison.. but did make me think about it.. a ford powerstroke diesel has a cps sensor that will up and quit and leave you on the roadside..... the cps ( cam sensor ) on a ford diesel is easy to change.. cut the wheel hard tot he side and a lil tab with 1-2 bolts hold it in.. unplug and plug new one it. like a 20$ part.. yet.. it will elave you walking on the roadside.. most powerstroke owners I know carry one in their glove box just for this reason..

soundguy

Sorry for going off tangent again but mine was on the bell housing at 11:00 o'clock sensing the crankshaft as you face the front from the driver side between the engine and fire wall. All I could do from top was to barely shine a light on it. I would not bore you with all the hoops I jumped thru just to get a socket on it, remove and install the new... just thinking about it brings cold sweat. My CPS was right under $70.

JC,

 

[J_J]

2LateIWon,

I am not so sure that you have verified that you has a good spark to the plug at the right time. You qre getting spark at some time, but when.

As far as the carb, let enough fuel in the bowl to fill it, then shut off the fuel, then try to start.

Maybe you have voltage to start, but none when in the run position. Check resistor.

Is that a 6 v coil or 12 v coil?

What is your battery voltage when starting?

If you are back firing, I would think the valves are sticking or timing is off.

You should also know that the point gap will change the timing.

Increasing the gap will cause the timing to be delayed . Set point gap before timing.

Set the plug gap, set the point gap, set the timing. Do not assume the plugs come set correctly.

With the right fuel mixture and the above items set, it should fire and keep running.

Let us know the results.

 

[2LateIWon]

Sorry last night was crazy at the 2Late's house hold so I didn't even get a chance to go out and do anything. To nights church but (depending on how tired I am) after church I'll try to check it out. If not my wife and kids will be gone (church camp) Thursday and I will have no excuse after that LOL Plus I'm going to see if I can con a friend of mine over to see if we can make something happen.

 

[Soundguy]

no start / run on that 8n ignition.

it's a key on / off for ignition, and a seperate thumb sized starter button on the trans cover that is neutral safety locked.

soundguy

 

[jinman]

In addition to what Soundguy said about the ignition/starter switch. I would say it is highly unlikely that you've changed the timimg unless the dist looks like it has moved in the clamp. If that clamp is tight on the base of the dist, then it would take a major mechanical failure to change timing enough to cause your problems. You can always run #1 piston up to the top of the cylinder on the compression stroke and then check the dist by looking at the rotor button to see if it is pointing to the #1 wire. in the cap. If it is close, my guess is that your timing has not changed. I believe it was mentioned before that this is also how you tell which wire should be #1 if you get them mixed up on the cap.

 

[J_J]

Looking back over the post, he never did say when the tractor last ran, and if it was running right then. Like Jinman said, turn the engine to #1 cyl at TDC, if that is the timing, and see if it will spark. If it does, that implies that the timing is correct or close and that the failure to run is probably a fuel problem.

One source quoted this.


Static timing is 4-BTDC on non-running engine.

 

[2LateIWon]

I bought this tractor a little over a year ago and have used the crap out of it. Just out of regular maint. I did a complete tune up except for the points and condenser. I've had other issues but never this or anything related. Just hydraulics, flat tires, lights. etc.etc. before this I had #4 spark plug wire short and start missing. So I replaced all the wires. I was brush hogging 40acres (this was about a month ago) was my last job with this. It mowed flawlessly with no problems. I was able to cut about 25 acres came back the next weekend and cut about 10 more acres then is started running rough. And just got worse from there under load. No load it would just miss a little. So I thought since I never changed the points and condenser out I should. So after that I changed them out is when I had all my problems. Before this it never had a problem firing up even in the dead of winter and not being started up for a few weeks. I could go out there and turn the key on pull 1/2 choke and she'd fire right up. That's why I'm so dumbfounded about why it's not running even after WE found out why it had no spark.

 

[Soundguy]

4'btdc at 400 rpm, and 18' max advance at 2000 rpm 27-31 dwell

soundguy

here's a page out of the ford pocket reference.. top line on the chart is the N