9N backfire

[johnchristy]

Thanks to you Bruce, I found the condenser wire was the problem. I now have spark but I get a pop,pop,bang. I have removed the front mount distributor and rotated the tang 180 but it does not make any difference in the backfire. I am guessing it is a timing problem but how do I make an adjustment if the engine is not running?

 

[souNdguy]

front mouints were designed to be static timed fairly easilly.

soundguy

 

[Bob Harvey]

Question?? How did you get the 'front mount distributor' to go back in after a 180 D rotation? The sucker has an offset 'tang' so it CAN'T be installed properly without being right . I think you got it wrong the first (or was it second) time. These machines are SIMPLE for a reason.

 

[Bruce (VA)]

It's nearly impossible to do, but if you did get the distributor in 180* out, chances are you broke something in the process....which might explain why it's backfiring. Like Bob sez, it has an offset tang & would really take some brute force to get it in wrong.

Assuming you haven't busted the distributor, I doubt you have a timing problem. Chances are you crossed the plug wires. Firing order is 1243, CCW.

But if you want to time it, this is right out of the I&T FO4 manual.....which needs to be high on your 'got to have' list:



Fig FO83-Distributor basic timing for front mount distributor. (I&T shop manual, FO-4)

Remove necessary wiring for distributor removal (plug wires from distributor cap and high-tension wire from top of coil). Unsnap the coil bail and distributor cap clips, then remove the coil and cap. Remove the two distributor mounting bolts. Remove distributor and take your assembly to the nearest workbench.

Set distributor points to .015 gap. Next, place a straight edge on the wide side of the tang on shaft as shown in fig. FO83. Rotate the shaft until the straight edge is ¼" away from the outside edge of the distributor mounting hole. At this distance, the distributor points should start to open. If not, loosen the timing plate lock screw and turn to advance or retard the timing. Keep adjusting until you get the proper ¼" setting. As you’re adjusting, eliminate backlash by turning the shaft backwards and bring the shaft forwards to measure your setting. This ¼" setting will get you static timing at top dead center. That’s what you want.

Reassemble in the opposite order. When mounting the distributor back onto engine, the slot in the end of the camshaft (front of motor) is offset. So the tang on the distributor can only mate easily to the slot on the engine camshaft one way. It will slide on easily without force and fit flush to the motor. If the tang is 180 degrees off, the distributor will have to be forced on and as soon as you tighten down the mounting bolts, the casting on the distributor will break. It may be in your best interest to mark the position of the tang with a couple of marks on the back of the distributor upon removal from the engine.
50 Tips

 

[johnchristy]

Thanks for the info. but I have read the manual and when I mounted the distributor I was careful to wiggle it to make sure that the tang fit the slot and did not screw it down until it was flush, no gaps. So I do not think that is the problem.
When I crank on it, it takes quite a few revolutions before it bangs but I hear a few pops before the bang.
I have watched wireing so as not to cross the wires. My manual indicated the cylinder number from front to rear of motor as 4,3,2,1 and the cap has numbers on it. So I do not think that is the problem.

 

[johnchristy]

I was careful not to force it because the manual gave me the warning. Maybe I just thought I had moved it 180. The distributor has a 9N stamp on it next to the tang but other parts of the tractor look like an 8N. Could this be any of the problem

 

[Bruce (VA)]

Nope. You've got it wired totally bassackwards. Number 1 is at the front of the motor, closest to the radiator. Standing in front of the tractor, the bottom left nipple on the distributor should have the plug wire going to #2 cylinder. Remember, firing order is 1-2-4-3, CCW. So, the wire from the top left nipple (facing the tractor) should be going to #1. I think you can figure out the other two wires!
50 Tips

 

[Kenster]

(quoted from post at 20:14:54 02/02/09) few revolutions before it bangs but I hear a few pops before the bang.
I have watched wireing so as not to cross the wires. My manual indicated the cylinder number from front to rear of motor as 4,3,2,1 and the cap has numbers on it. So I do not think that is the problem.

As long as the cap is numbered correctly. Who knows what we'll get from China these days. You have the wires numbered correctly on the motor. The order on the cap should be 1,2,4,3. Counter Clock wise.

 

[Bill M (OH)]

As below, front mount distributor only goes in one way. Looking at cap from front of tractor plug wires are as follows: 10 o"clock is #1 (at the front of the engine), 8 o"clock is #2, 4 o"clock is #4 (Back of the engine) and 2 o"clock is #3. Backfires are usually caused by points not set right
on a front mount - gap is 15 thou - rather than timing being off. If you do need to check the timing, get an I&T FO4 manual - even gots pictures to get"er done.

 

[johnchristy]

Thanks Bill, The .015 is a pretty small gap. My feeler is .016 or .014. How precise do it need to be. I am having a problem getting the gap to close. Do not know if that is because it is old or if some other restriction. The screw on the side to advance or retard, does that have anything to do with the point gap?

 

[Anonymous-0]

You are not reading the manual right.#1 starts at the radiator.Take some time to study then do the work.

 

[Bruce (VA)]

Gap it at .016 & don't worry about it. If you have the correct cap, the timing adjustment screw will not interfer with it. Timing and point gap are related; that's why you set the point gap before you set the timing. But the difference between .015 & .016 on the gap isn't causing it to backfire. Having it wired backwards will; did you think #1 was at the rear of the end as you said earlier, or was that a typo?
50 Tips

 

[GB in MT.]

[b:349cf9b215][i:349cf9b215]
johnchristy;
Read the last two replies from Bruce, then take this picture with you and set up your wires to match.
Should stop the backfire/pop,pop,pop!!!!!!!!!!

Gary [/i:349cf9b215][/b:349cf9b215]

 

[johnchristy]

Thanks to all of you! Yes I had the wireing backwards. The FO 4 was not that much help and page 47 appears to be in error.
Anyway I put the right wires to the right places and she fired the first time. No hard start on this one now. Maybe that will come later. Thanks again!