Ignition Issues Again!

850EV

850 Project
Well... I’m back.

I’m having a heck of a time getting my 68 850 to fire. I have the timing marks lined up, compression stroke. I’ve tried on cylinder 1 and 4. I have fuel visibly going down the Venturi. Strong vacuum coming from the carb also.

My timing light shows the marks lined up when spark travels. I’ve taken each plug out to check for spark. All good. Only thing I notice is the ignition coil gets rather warm to the touch after multiple attempts. It’s a 3.4Ohm resistance coil for my points. Set at a .016 gap. Checked 3 times.

What am I missing? The warm coil insinuates resistance, so is 3.4 too high? Once in a great while it’ll cough back at me but only once.
 

dnudelman

True Classic
Like I mentioned in the youtube comments, I hope you're not still thrashing the starter. I've never set timing using the method in your video.
1. Set the points to correct gap
2. Set static timing at 8BTC
3. Quote "My timing light shows the marks lined up" which tells me you set timing based on TDC. Since you have an 843 not a 903, your timing should be set up at 8BTC
 
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850EV

850 Project
I’ll try that again. May be a dumb question, but how do I know where 8 degrees BTDC is when setting it up initially?
 

Frank L. Di Gioia

True Classic
While cranking try rotating your distributor CW and CCW a small amount and if it's showing signs of "wanting" to start you're getting closer. Don't stare down the carb while doing this and don't crank too long or the starter will cook. Did the plugs show signs of gasoline on them? If dry "pump" it 1/2 dozen making sure accelerator pump is squirting gas down the throat and try again. If wet let them dry and reinstall.
 

kmead

Glutton for punishment
You can set the timing on an 850 without cranking at all using a 12v light bulb wired from the points to the coil taking the place of the wire of the standard wire or inline with it. Turn the ignition on with the bulb connected and then with the ignition on, adjust the distributor until the light just lights as you rotate the distributor.

Set the engine in time with where it should be (#1 or #4 it matters not), in this case 8° btdc which is approximately 1/6 of the distance from TDC to 45° counter clockwise. You can determine this point pretty easily using a sewing measuring tape or other typical means of dividing distance equally. Using the pulley as a guide mark the face of the timing chain over with a light mark or using tape apply a sharpie mark at the correct point.
 

dnudelman

True Classic
Just watched your latest youtube. Some observations.
I didn't see the balast resistor on the coil. Perhaps its mounted elsewere. You might check the wiring, perphaps thats why your coil is warm.
The coolant recovery bottle, there are lots of youtube videos showing how to clean it. It worked well for me.
As for the hose, clear vinyl tubing from the hardware store works.
Radiator fan. Do you have the original shroud and yellow fan? Might be a better solution than an electric fan.
Is the generator too close to your starter? You might want to fit an alternator. Jeff Stitch has some for sale on this board.
 

850EV

850 Project
Just watched your latest youtube. Some observations.
I didn't see the balast resistor on the coil. Perhaps its mounted elsewere. You might check the wiring, perphaps thats why your coil is warm.
The coolant recovery bottle, there are lots of youtube videos showing how to clean it. It worked well for me.
As for the hose, clear vinyl tubing from the hardware store works.
Radiator fan. Do you have the original shroud and yellow fan? Might be a better solution than an electric fan.
Is the generator too close to your starter? You might want to fit an alternator. Jeff Stitch has some for sale on this boar
I do not have a coil resistor installed as I never had one from the beginning. What kind would I need? (a link to it would be helpful) The wiring diagram does not show one. I will be cleaning the bottle to save some money. It has a large crack at the top but luckily they aren't pressurized. I have the original fan and shroud, but I think its cracking pretty bad due to its age. Replacements I have found are well over $100, so if someone has a spare I would love to wheel and deal! As for the generator, it barely touches, but with an alternator I think it requires some other parts, not just a swap.
 

dnudelman

True Classic
1. bottle - epoxy is your friend
2. Shrould - Mothers VLR does wonders.
3. Resistor - right above letter D
1617640624768.png
 

dnudelman

True Classic
The Alternator may bolt on, it has its own bracket so you would remove the generator bracket. You will need an external regulator unless you find a later one with an internal regulator.
The usual parts suppliers don't show a resistor for sale, ebay has some that say they will work. Perhaps there is an answer here.
 
If the coil primary resistance is in the 3 to 4 ohm range, it probably has a built in ballast resistor. If it is ~2 ohms or less, it requires an external ballast and would likely burn up if run without one due to too much current and the resulting power dissipation.
 

850EV

850 Project
The Alternator may bolt on, it has its own bracket so you would remove the generator bracket. You will need an external regulator unless you find a later one with an internal regulator.
The usual parts suppliers don't show a resistor for sale, ebay has some that say they will work. Perhaps there is an answer here.
What is the normal resistance on it? Maybe there is a universal one I could find? Just an idea.
 

Jörg

Low Mileage
Strangely there is no ballast resistor in the diagram in the operating instructions, but you can see one in a photo in the operating instructions.
The original ignition coil was the Marelli BZR202a with resistor.


40940189sl.jpg
 

Jefco

Daily Driver
Turn the ignition on with the bulb connected and then with the ignition on, adjust the distributor until the light just lights as you rotate the distributor
This is only correct if you turn the distributor backwards (ie antirotationally), the ignition fires when the points open (not when they close), so if you turn it forward, it's when the light just goes out.
 

850EV

850 Project
Update:
Got it running! I just had to better adjust my initial timing and no resistor was required. (3.5 ohm coil) Now I just need to adjust my carb screws to lower the idle speed and finer tune with my timing light. It only wants to run with half choke, but once I open it all the way it dies. She wants more fuel apparently! Points got set to .018, which is on the larger side of the recommended setting scale.
 

Jefco

Daily Driver
I ran across my old static timing light the other day; I soldered it up nearly 40 years ago, when I had a '75 124 sport coupe. Thought it was broken years ago!
IMG_2153.JPG
 
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