HELP! = Frustration Sets in...........

[AnvilheadTX]

My 48 8n (front mount) is sounding sick under full throttle and the normal power is not reached. There is NO backfiring, just some of that sick gurgle coming out the exhaust (at full throttle). She idles fine and is blowing no smoke anywhere.

Here is all what I have done in the past few weekends:
New points
New condensor
New rotor
New coil
New coil cap
New spark plugs
4x checked spark plug wires

She is running, so therefore SOME gas is reaching the block. She will idle all day and sounds good at idele.

The only odd ball thing is that when I touch the #4 cylinder sprak plug cap (when running) I take a shock. I touch only the plastic cap. Does this indicate a short somewhere and could this be a problem.

I did the old screwdriver test several times and the sparks were not as bright as I would think...of course it was in the middle of the day. Nonetheless, there is enough sparks to fire and run.

Any thoughts - electical, fuel, air? There are no unusual sounds from the block, no unusual smoke, so I am hoping this is not a valve or pistion issue.

 

[AnvilheadTX]

Oh I forgot to add...12 volts

 

[Paul in MN]

With the diagnosis of a sick gurgling sound at the exhaust, I'd suspect something in the exhaust pipe or muffler. A neighbor did all the things you have already done and then brought it over for me to see if I could make it better. The strange exhaust sound was the tip-off...the exhaust system was jammed with acorns. I thought about taking off the muffler and exhaust pipe, but then an easier way appeared. I just poked a hole (with a steel rod) through the pile of nuts and shells by pushing the rod forward through the exhaust pipe and muffler. With the restriction reduced, I started the motor and just let it idle for about 10 minutes and then reved it up a few times. The nuts were nicely toasted (somewhat burned) and came flying out. Then the engine was perfectly normal.

I think the rodents gottcha.

Paul in MN

 

[Joe (IN)]

Shocked when you touch the cap, lazy, orange sparkies, and it runs like crap above idle. You've changed everything in the ignition system except for the wires, which you've "checked" 4 times. She's got all the classic symptoms, Tex. You're tractor is screaming for a fresh set of plug wires. The resistance is too high through the wires and the insulation is leaky. Your sparkies are looking for someplace else to go. When you grab the cap, they pick you. I bet if you fire it up after dark, it'll look like the 4th of July. You've probably got sparkies going everywhere EXCEPT the plugs and you just don't see it in the day light. Quit wasting your time checking them and just replace them. Use ALL COPPER tractor plug wires. DO NOT put carbon core automotive wires on it. I guarantee your problem will be solved.

 

[teddy52food]

I heard a story the other day about a MF diesel tha wouldn't run right. He took off the inj pump & had it rebuilt but it still wasn't right To make a long story short, mice had filled the muffler with dog food.

 

[old]

I agree with both thoughts on this. Exhaust system maybe clogged up and or the plug wires getting bad. Exhaust system is easy to check with a long rod of some sort and so are the plug wires just by starting it in the dark.
Hobby farm

 

[AnvilheadTX]

They are only 6 months old and mint.....except when she was running good last weekend the fan nicked one and cut into the wire a bit. She ran fine after that and I have covered with electical tape.....but just ordered a new set to be sure. But anyhow, the #3 wire was nicked and I got shocked on #4.

Also, the wiring harness is a rat"s nest. I was trying to get by until I am finished with the tractor in the fall THEN I planned on reqiring her. Guess what I am doing next weekend? The deer plots have to wait.

Also what is the best way of labeling spark plug wires so I never have to play the silly "am I hooking the right plug up" game again. It would be cool if numbers were imprented on the spark plug wire rubber caps like the numbers on the distributor cap itself?

 

[old]

You are using true wire spark plug wires right???????? If not thats part of the problem also since plug wires made for cars don't work well on tractors
Hobby farm

 

[Jerry/MT]

Make sure that you have the correct firing order, 1-2-4-3.

 

[Phil (NJ,Az,Sask)]

(quoted from post at 20:54:22 09/09/07) . It would be cool if numbers were imprented on the spark plug wire rubber caps like the numbers on the distributor cap itself?

That sounds like you think those Numbers on the distributor CAP belong to the Distributor, THEY DO NOT. They are Spark plug Numbers and the # 4 must go to # 4 Plug ETC. These tractors will start & idle with 3 & 4 Swapped (wrong) but you will have no power.

JMHO

 

[souNdguy]

I'd also advise to change the plug wires, and to verify 1-2-4-3 fire order.. it's so easy, especially on the front mount, to confue that.

next I'd look at wiring.. if you have bad connections at the key switch.. you aren't geeting good power to the coil..

use jumper wire clips to help diagnose the problem.

Your indication of a shcok tells me that the insulation is leaky / weak sparks not wanting to jump the gap.

Pull that plug too.. just for a looksee.


Soundguy

 

[AnvilheadTX]

Thanks for the tips. I do have the correct wires (although one is damaged)and I confirmed the firing order (although I agree it is VERY EASY to screw this up).

The wiring system is old and as I said, I beleive I am going to change it out this weekend along with the spark plug wires.

 

[Mo teacher]

No one mentioned carb adjustment. If the main jet is alittle lean it will idle perfect but will not allow enough gas for high speed or a hard pull. My 2 cents.

 

[Anonymous-0]

A problem I had when changing points on my 9n, I got the distributor a half a turn off when reinstalling- pushed the retainer clip and points plate out, but it still bolted down, but mine wouldn't fire at all till I corrected it, then she purred! Makes me wonder if your timing is off.