8n won't start

[Mike Dermott]

Hi!
I'm a new member and live near Orangeville Ontario Canada. I'm a commercial air-conditioning mechanic/service manager by trade and I only say this to display that I do have a mechanical aptitude, (but I'm not an automotive or tractor mechanic).
The 8N came with the property, can't read the serial # but it has a front mount distributor and my guess would be circa 1951. I've managed to keep it working for the last 12 years, and had a mechanic convert it to 12 volt, but this year its got me seriously frustrated. It ran OK when I parked it late last fall and now it wont start.
First I had no spark- First installed new 12 volt can, rotor & cap, when I removed the distributor & installed new condenser, points seemed ok, (i didnt notice at the time that the points weren't opening properly - tries to start but no go.
Second installed new multi strand copper plug wires, & plugs- tried to start but no go intermittant & weak spark.
Third removed distributor again and found that the fiber lever on the movable contact was worn out and points hardly opened. This time I thought I pegged it! Installed & gapped new points to 15 thou., and setup opening timing point. Sorta started but couldn't keep it running, sputters, backfires & dies.
Fourth removed carb & cleaned, drained gas & added new "super grade". Again it sorta started but no go.
Fifth removed carb & rebuilt, (if you can call it that), kit only comes with needle & seat, float rod, and some gaskets.) Removed & cleaned jets, ( the one in the bottom doesn't seem removable so I didn;t try. I also installed new ignition switch. Still no go!! really starting to get p o at this point.
sixth try removed carb again removed all but the one jet and blew everything out with carb cleaner in both directions to ensure no blockages. Still no go!!! Lost my sense of humour.
The only thing I can think of now is that the carb is NFG as everything else has been replaced or tinkered with.
If memory serves I have 2.9 ohms from the ignition through the 1.2 ohm resister and 1.7 ohms through the new square can coil. somewhere I read it should be 4 ohms but with what I have should give me a stronger spark
I think I was getting 100 psi on #1, 2, & 3, and 80 psi on #4.
What do you guys think!!
:confused2:
Thanx, Mike

 

[Muhammad]

Welcome to TBN.

 

[SSdoxie]

Have you pulled the plugs and grounded them while cranking engine to see if you have good spark in all cylinders?

To help identify or rule out carb, take off the air intake hose at carb and use a srpay bottle with gas and mist it into the carb while carnking. if it runs while misting the gas and not on its own you carb problem. If it makes no difference and you have spark at all 4 plugs, then I would suspect ingnition timing.

 

[CompactTractorFan]

Welcome to TBN!!! If you need some more help, try the Parts/Repairs section.

 

[Mike Dermott]

thanks, I like the mister idea

 

[mostly_gas]

Pull the float bowel and see if you have good fuel flow and good fuel. If I remember correctly the fuel shutoff had a reserve position that would pull from the bottom. Check plug color/condition after it tries to run. by the way if they are wet I clean them off with a propane torch before continuing.

 

[Egon]

To help identify or rule out carb, take off the air intake hose at carb and use a srpay bottle with gas and mist it into the carb while carnking.

This procedure can get interesting if there is a backfire. More than one person has had serious burns or been killed doing this.

When carburators were king this was a not uncommon incident.