my 8n is slow...

ykp53

Member
I just bought my first tractor. It is a 49 8n that was restored. It has been converted to 12v w/a petronix HEI system. When I am in first at full throttle I think I could speed walk faster than it. in second its faster but bogs down when I start going up hills. It really feels like I am running at about 1/2 throttle. Also there is no noticeable difference between 0 or 1/4 or even 1/2 throttle. Its not until above half that you can hear the engine speed up. What do I need to check?
 
Could be a few things throttle linkage, governor,
fuel flow even a dirty air cleaner. check these
first and post back.
 
How does the engine sound? Is it missing or sputtering or what?

I would first check your plug wires to make sure none of them are burned anywhere or loose at either end.

Next you need to check fuel supply. Remove the plug at the bottom of the carb. The gas should run out in a steady stream filling a pint jug pretty quickly.
 
Since I am new to these what will I need to check with the throttle or governor? plug wires look good?
& engine idles smooth no stumbles or back fires. How fast should the tractor move at full throttle in first?
 
If your linkage is free and not binding, your symptoms sound
like the governor is not functioning. Can you run the throttle
rod connected to the carburetor by hand and get correct results?
Does the governor fight you when you try that? It should.

Engine RPM should be roughly 2000 RPM max. governed.
Throttle response should be fairly linear across the range

We'll talk about "restored" and "converted to 12v w/a petronix
HEI system" another time. To me, they are mutually exclusive.

But that's not your issue, so let's get it running first eh?

Welcome to the forum! :)
 
Sounds like it could be in the governor. Take the throttle linkage
going to the carb and open it up some by hand with the engine
running. See if it will rev up like it should then, also feel to see if
the governor pulls back on the throttle rod to carb as it should.
Just be safe when working on a running engine. Get a copy of the
Ford manual, it has steps to check governor operation.
 
ykp53,At full throttle 2200,RPMs,1st=4.19 mph, 2nd=5.38 mph,3rd= 7.40 mph,4th=15.47 mph
reverse=6.88
 
(quoted from post at 17:58:27 03/20/15)
We'll talk about "restored" and "converted to 12v w/a petronix
HEI system" another time. To me, they are mutually exclusive.

But that's not your issue, so let's get it running first eh?

Welcome to the forum! :)

Your right restored isn't the right word. In the car world it would be a resto mod....
 
Governor methinks..... as several have pointed out...your symptoms were mine to a T on one of my 8ns...the rebuild fixed the issue!!

Post back!!
 
ykp53.......yer 49 8N has the weird 4-nipple front mount dizzy. Check yer firing order......1,2,4,3. #1 is next to radiator. Engine will start EAZY but won't have enny power just as you complain. While yer carbie could be part of yer problem, sparkies are most likely. Recommend AutoLite 437's gapped 0.025". I'm notta fan of Pertronix and the 4-nipple dizzy. you can't fitt the transistor parts inside the dizzy and Pertronix instructions SUCK. There is 'nuttin' wrong with a 12-volt conversion. Points (0.015") and condenser work just fine. 12-volts on 6-volt starter really spins for faster starting and does NOT hurt it. .......electrical Dell
 
(quoted from post at 03:54:16 03/21/15) Check yer firing order......1,2,4,3. #1 is next to radiator.
I will check this. I did notice that my fuel shut off is not working correct and there is no difference with it full off or full on, so I will change that out and check the spark plugs and report back.
 
" I did notice that my fuel shut off is not working correct and there is no difference with it full off or full on, so I will change that out"

No, that's the way it's supposed to work.

It's gravity fed.

Two turns is all you want for normal operation.That gets you 9 gallons.

Open it all the way to get to the one gallon reserve.

All this is in the manuals. If you don't have them, it would be a wise investment. (see tip # 39)
75 Tips
 
(quoted from post at 08:43:23 03/23/15) " I did notice that my fuel shut off is not working correct and there is no difference with it full off or full on, so I will change that out"75 Tips

Bruce, what I was trying to say that even when full closed I am still getting fuel. I can not shut it off and want to make sure I don't drain everything when the tractor is off.
 
(quoted from post at 10:41:21 03/23/15)
Bruce, what I was trying to say that even when full closed I am still getting fuel. I can not shut it off and want to make sure I don't drain everything when the tractor is off.

it will run for a few minutes even after shutting the fuel off - takes a moment to drain the carb.

wally
 
Wally it ran for about 5 mins and showed no sign of slowing down with it in the full off position.

I checked and I do have good gas flow when the lower carb bolt is removed. If you run up the throttle by hand you can feel a resistance and when you hold the brakes and let out the clutch whole in gear the engine will rev up a little so i think the govener is working. I also checked the spark plug wires and they were In The right place. I did notice there was a lot of paint on the governer and throttle rods and it seems that the throttle response is a little better after some use. I am wondering if i had a binding issue due to excess paint on parts? I know it might be a long shot, but you never know....
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