Busted 8N

bigdeano · Oct 18, 2017

I'd try another new condenser. I've seen new ones that were bad.

TractorGuy · Oct 18, 2017

I would NOT recommend using starting fluid to check for intake leaks. You can actually spray water on the areas under suspicion for greater safety. Anything that gets sucked in where it shouldn't will change the sound. I have used carb cleaner or WD-40 but never ether.

rScotty · Oct 18, 2017

Tractorable said:
Yea true, I'm just hard headed and like to fix things myself. I know if I take it to a mechanic it'll be some little thing that I missed and I'll be kicking myself. But the fields haven't been mowed in a couple months and you're right I may be better off just paying some one to fix it.

OK, I'm going to go way out into left field...because it sounds to me like you've hit all the normal things to look at and without any change.
What if the intake valves to those two cylinders are simply not opening up to allow new charge to come in? Something might have happened to the cam, or valve lifters, or rockers, or the valve clearance. And if you only do a compression test you aren't going to pick that up.

So it it were me, I would take off the valve mechanism cover - not sure which cover it is on the 8N, but it's where you adjust the valve clearance. And then I would crank the engine over and physically watch to see if all the valves are opening up when the engine is cranked over.
If you want to crank it by hand, just take out all the spark plugs and you might be able to turn it with the fan or a wrench on the front crankshaft nut.

And if you don't know the 8N valve sequence then just follow this old rule which works for any engine:
For the valves on any cylinder, adjust the intake when the exhaust valve is just beginning to open....and adjust that cylinder's exhaust valve when the intake has just finished closing. Those are the points of maximum clearance.
Enjoy,
rScotty

mapper · Oct 18, 2017

"I'm about to push the tractor off a cliff and go buy a new kubota."
Even if you fix your problem a new kubota (or any other color) might be tempting. I replaced my 8n which I had owned for 30 years, with a new MF a few years ago. The difference in what I can do with the new tractor is amazing, not to mention how much easier it is on my body to operate it. Keep the 8n as a pet and get something new. Hey we all need someone to ask us what to get so we can help you spend your money

Tractorable · Oct 18, 2017

rScotty said:
OK, I'm going to go way out into left field...because it sounds to me like you've hit all the normal things to look at and without any change.
What if the intake valves to those two cylinders are simply not opening up to allow new charge to come in? Something might have happened to the cam, or valve lifters, or rockers, or the valve clearance. And if you only do a compression test you aren't going to pick that up.

So it it were me, I would take off the valve mechanism cover - not sure which cover it is on the 8N, but it's where you adjust the valve clearance. And then I would crank the engine over and physically watch to see if all the valves are opening up when the engine is cranked over.
If you want to crank it by hand, just take out all the spark plugs and you might be able to turn it with the fan or a wrench on the front crankshaft nut.

And if you don't know the 8N valve sequence then just follow this old rule which works for any engine:
For the valves on any cylinder, adjust the intake when the exhaust valve is just beginning to open....and adjust that cylinder's exhaust valve when the intake has just finished closing. Those are the points of maximum clearance.
Enjoy,
rScotty

Thanks for the insight. When I pull he manifold, I'll pull the valve covers and inspect them for correct operation. I have a service manual and will adjust to spec.

Tractorable · Oct 18, 2017

mapper said:
"I'm about to push the tractor off a cliff and go buy a new kubota."
Even if you fix your problem a new kubota (or any other color) might be tempting. I replaced my 8n which I had owned for 30 years, with a new MF a few years ago. The difference in what I can do with the new tractor is amazing, not to mention how much easier it is on my body to operate it. Keep the 8n as a pet and get something new. Hey we all need someone to ask us what to get so we can help you spend your money

LOL, you're so right. I am going to buy a new Kubota L or Yanmar YT for my eight acres. I bought the property two years ago and the 8N as a short term stop gap until I could afford a new one. The 8N will be for wagon pulling duties and I'll put the new one to work doing everything else.

But first things first, gotta get this 8N running.

jaxs · Oct 18, 2017

Since you are still trying to fix this thing the least you should do is stop throwing things at it and begin a systematic approach. You have repeatly been told to pull plug wires but I don't se where you reported the results of pulling wires. In your original post,you said but it stills runs like its firing on two cylinders.
Is it dead missing on two cylinders? (you can tell by removeing 1 plug wire at a time). Or is it simply running so bad it sound's like only two are hitting? There's a huge difference and each requires intirly different troubleshooting methods.

Tractorable · Oct 18, 2017

jaxs said:
Since you are still trying to fix this thing the least you should do is stop throwing things at it and begin a systematic approach. You have repeatly been told to pull plug wires but I don't se where you reported the results of pulling wires. In your original post,you said but it stills runs like its firing on two cylinders.
Is it dead missing on two cylinders? (you can tell by removeing 1 plug wire at a time). Or is it simply running so bad it sound's like only two are hitting? There's a huge difference and each requires intirly different troubleshooting methods.

I'm actually on a business trip right now but will be back in town soon to verify the plug wire routing. Thanks for your advice.

jaxs · Oct 18, 2017

Tractorable said:
I'm actually on a business trip right now but will be back in town soon to verify the plug wire routing. Thanks for your advice.

Okie Dokie,let us know what you find with wire routing. Hopefuly a couple just got crossed and that will fix it. If not,see if pulling one at a time make's a difference in how it runs. Travel safely.

rScotty · Oct 19, 2017

Tractorable said:
LOL, you're so right. I am going to buy a new Kubota L or Yanmar YT for my eight acres. I bought the property two years ago and the 8N as a short term stop gap until I could afford a new one. The 8N will be for wagon pulling duties and I'll put the new one to work doing everything else.

But first things first, gotta get this 8N running.

If it wasn't in the plug wires, I'll bet you find it when you look how the valves are working.
And I hear you on modern tractors. We bought an old - new in 1958 ! - JD as our "gap filling" tractor and know of two friends who bought old MFs much like the 8N. And another who has an even older massey Harris!
Here's the thing....ALL of us have newer Japanes styel 4wd loader tractors now that we use on a daily basis...but ALL of us kept the old "gap-filling" tractors for just the same reasons you put forward - To pull a wagon and be a backup. We all still have them! After all, those old american-made farm tractors wouldn't bring anything on the used market, but every one of them runs and works just fine. And probably for another 50 years, too if we can find decent gas to put in them. They are family members, now.
Hint: If your old gas tractor sits for months or longer, put aviation gas in the tank. You aren't using much gas anyway, and av gas is the best quality i absolutely no water or alcohol in it.
rScotty