What to ask when looking at a Jubilee?

[JoeinTX]

Gabe, the NAA/Jubilee is a pretty well bullet proof machine if you get it in good shape. I've used an actual '53 Jubilee (on the farm) for 20 years with one rebuild in that time. Adjusting the points set and the occasional fouled plug are the biggest problems we ever have with it.
I moved to the big city about 5 years (gotta follow the paycheck) but I've been crasy for a little tractor action ever since. For about the last year I looked/shopped/priced/dickered/almost bought/had second thoughts about buying a new compact tractor and using it to piddle around here and had pretty well settled on one of the little Mahindra 42 hp package deals. But, I ran across a very nice looking little 8N one day-it needed a little TLC but for $1000 setting on 4 good tires and no obvious signs of abuse I snapped it up. Right now it's in the shop having a number of odds and ends done to it but it will make a fine little tractor for a long time once it's done. It might be a good idea to let the dealer or a recommended tractor mechanic have a look at it and see how much it'll cost you to make a very productive rig out of it.

 

[GabeTX]

After stopping off at TSC and a couple auto parts store (naturally, TSC only had 3 H12's, and the first auto parts store didn't have any...) I bought a set of plugs.

Replaced all four sparkplugs and all the wires.

Is backfiring like crazy an improvement? /forums/images/graemlins/confused.gif It idles a bit smoother, but now whenever I put any kind of load on it (moving the tractor, even in first, spinning up the rotary cutter while stationary) it starts backfiring like mad. I drove it a couple hundred feet, and afterwards there was oil dripping out of the air intake screen from the air filter and a hole lot seeping out from where the oil container hooks in.. On the positive side, I won't have to lubricate anything on underneath the air filter for a long time.

Checked all the sparks, just to make sure I didn't mess it up, and I was able to draw a good, regular spark from all of them. I did notice something interesting, though.

When I pulled the first wire, I didn't notice any change at all in the engine (same as yesterday). When I pulled the second, it started to struggle. Same with the third. When I pulled the fourth, it got considerably smoother, and got rougher when I plugged it back in.

The valve comment you made earlier is scaring me now...

 

[GabeTX]

Oh I should add--you (jinman) mentioned the governor.

One of the things I noticed as I watched it backfiring through the carb was the throttle rod being actuated whenever there was a big stutter (this was with me off the tractor and not touching the throttle lever).

I assume that was the governor doing its thing and trying to keep the engine running by giving it more gas when it slowed down? If so, hopefully that's one expensive component that can be ruled out as a problem... /forums/images/graemlins/grin.gif

 

[jinman]

Gabe, you are having fun, aren't you? /forums/images/graemlins/crazy.gif /forums/images/graemlins/smile.gif

It sounds to me like there are a couple of possibilities, but they both relate to timing. Are you absolutely positive that your spark plug wires are installed correctly? That can cause severe backfiring. The firing order is 1-2-4-3, so find the wire going to #1 and then proceed around the distributor to see if the wires are connected to the right spark plugs.

Next, you want to make sure your timing is close to correct. It should be about 4.5° before TDC of the #1 piston. The easiest way to check this is to look at the distributor and the position of the #1 plug wire. Mark that on the outside of the distributor (not on the cap) and then remove the distributor cap. Remove the #1 spark plug (#1 is at the front of the engine). Hold your finger in the plug hole and turn the engine over with the starter. Your finger should "pop" off the hole from compression at the exact time the rotor button points at the mark you just made on the outside of the distributor. You can also remove all the plugs and turn the engine over by hand and look for the piston thru the spark plug hole. You just have to make sure the piston is on the compression stroke instead of the exhaust stroke. If you can't see the piston, you can use a flashlight or carefully put a pencil into the spark plug hole to feel the piston coming up to top dead center (TDC).

If your timimg is off you need to loosen the clamp on the base of the distributor and adjust the timing. I doubt that it's that much off. It it looks like it hasn't ever been adjusted, I think I'd just leave it alone until I could get a timing light and check the engine timing.

The only other thing that can effect timing is the flyweights inside the distributor. They are down below the plate the points and condenser mount on. Those weights use centrifugal force to advance the timing as engine rpm increases. If the flyweight springs are defective or the weights are gummed up, that could be a problem, but I think that's pretty rare.

Gabe, the last thing is to make sure your distributor cap is not cracked and/or dirty inside. When there is dirt or moisture, the spark can jump around under load and can cause the tractor to run rough.

The final thing you need to do is to run a compression check. I don't know the pressure off the top of my head, but all the cylinders should be within a few pounds of each other. If you have a compression problem on that cylinder that's not firing, that could be your problem with the miss and could be caused by bad valves, bad piston or rings, or a leaky head gasket. That would also mean that under load when that cylinder fires, you could be getting flashback backfire thru the carb.

I wish I had more time right now to give you more details, but I gotta run. Maybe I've given you a few ideas to check. The most likely in my estimation is the plug wires are installed incorrectly (not in the proper firing order).

 

[GabeTX]

#1 is at the front of the engine? /forums/images/graemlins/shocked.gif

I changed the spark plug wires one at a time to prevent a mix up like this, and I double-checked that the firing order was 1-2-4-3, but since the #1 spark plug wire (as labelled on the distributor cap--the spark plug wire at about 8:00) was going to the rear-most spark plug I assumed that was cylinder #1.

So I guess the current firing order is 4-3-1-2 /forums/images/graemlins/crazy.gif

Maybe that's why it's not working too well. /forums/images/graemlins/smile.gif Now I'm gonna be antsy all day waiting to get home and try it out...

 

[jinman]

Gabe, I can take a picture of my distributor and plug wires for reference, but I won't be home until late tonight, so I can't get that to you now. Here's what I'd do. Remove the plugs and distributor cap while your engine is still cold. Hold your finger over that #1 (forward) plug hole and use the the starter to rotate the engine. Look at and mentally note the position of the rotor when the #1 pressure pops your finger off the plug hole. When you put your distributor cap back on, that #1 wire should align very closely to the position you noted. I'm suggesting this because it seems someone has really done a "job" on your timing. Who knows how far off they have the distributor adjusted from TDC. Also, I told you the timing was set for 4.5° before TDC and YTMag says it's at 8° BTDC, so I probably gave you the wrong setting. You need a timing light and to find your timing mark on the flywheel for that level of adjustment anyhow.

I hope it's something simple like the plug wires installed wrong. That would really be nice, but you don't want to assume that's all the problem. There could be other "booby traps" waiting to snap you up at any minute. /forums/images/graemlins/tongue.gif

 

[GabeTX]

Wow!

What a difference correct ignition order makes. /forums/images/graemlins/grin.gif Thanks!

I did the "put your finger on the hole and crank" thing, rewired the plugs and rotated the distributor so that #1 wire was right there. The idle was still rough, but I the backfiring ceased, I could turn the throttle all the way down without stalling it, and there was WAY more power. The mower runs just fine in 2nd (didn't test 3rd yet), and when I raised it and put it in 4th I moved uncomfortably fast without the engine lugging at all (I don't think I'll have much use for 4th on my little 4 acres...).

MUCH better.

A shipment from just8n's with a new proofmeter, new water temp gauge, an oil filter, and some minor missing/rotted bits that I noticed wll be arriving tomorrow or the day after. I already have a timing gun and found the little tab you can swing to look at the fly wheel, so I ought to be able to give it a proper tune-up no problem once I get the proofmeter on (I felt so clever when I figured out I could remove the old one by removing the battery and going in underneath it--no sheet metal removal required /forums/images/graemlins/laugh.gif ).

Of course, I'm assuming that the proofmeter is accurate enough for a tune-up....

The only new problems I noticed today were the gas tank leaking near the front after it'd been either shut-off or idling for a long time. It instantly stopped when I removing the gas cap to let the pressure out. There was a lot of pressure in there when I did that. Maybe I just need to add more gas (the petrochemical) to reduce the volume of gas (the phase of matter) in the tank? It was pretty low.

Also, the throttle lever didn't like staying put after I opened it up. Wanted to creep down.

But those are relatively minor now that the engine is actually developing some power. With an oil change, a working temp gauge, and a working proofmeter (mostly so I keep the PTO at the right speed) I'd feel comfortable mowing with it.

 

[jinman]

Yabba dabba doo! Ain't life grand? /forums/images/graemlins/grin.gif

I think you are definitely getting the hang of things on this tractor. I'm so pleased I could help you get it running. You just don't know how close I came to not mentioning the #1 cylinder was at the front of the engine. I didn't want to insult you. /forums/images/graemlins/blush.gif But then I thought about the fact that many people have never worked on these machines, so they just never have the opportunity to learn like I did as a kid. I'm very proud to have been able to help you. If you need more info, I'll try to help and Soundguy is also a great source. /forums/images/graemlins/cool.gif

 

[djradz]

All this talk is making me jealous! /forums/images/graemlins/frown.gif Someday, I hope to restore a 600 or 6xx series tractor, but in the meantime I'll just have to continue to enjoy your successes. Helped my father restore his old Ford 981 (yes with SelectoShift) and that was sheer joy, well most of the time. /forums/images/graemlins/tongue.gif Glad to hear it's proceeding well.

If you want some really good history on these old Ford Tractors, short of buying a book, and maybe even better than some books, visit: Ford Tractor History

There must be a gas tank vent somewhere, either in the cap or elsewhere - must be!

 

[Soundguy]

I agree with Jinma... deffinately use a 30w oil.. perhaps 40w if you have 95' weather and are working hard.. besides 2 oil changes a year won't hurt a bit.

First get the plugs and wires, cap, and rotor changed.. points to if it hasn't already been done... Then start with why it runs poorly.

Could be as simply as a lean main jet In to lean, out to enrich on the downward pointing main jet. Turn 1/8 to 1/4 turn and then goose throttle. Stumbling is too lean.. sooty black exhaust too righ.

That tractor should mow fairly good in 2nd with a6' cutter. Also.. brush is easir to mow than thick grass. That said.. if you are mowing over 1' tall grass, stay in 1st. Also.. as another option to maink 2 passes at half height.. consider taking less of a bit.. say.. make a 4' pass instead of full width. 4th gear isn't for anything but driving down the road. You can't get pto rpm up to corect levels untill you are going around 10-12 mph.. etc and that's no way to mow on an NAA!

It shouldn't try to stall if you are at about 450rpm or more.. if it does.. it's governor/distribuitor advance.. or carb.

Soundguy