8N Throttle

hunkydory · Feb 21, 2021

Early 1950 8N with front distributor. The throttle rod goes down into what they call a "lever assy", which connects to the rod to the governor.

The lever assy looks to be a clamp-fit to the throttle rod. Is this correct?

I think I need to adjust mine because the idle position has the lever hitting the battery box and it's impossible for the rod to move that far. The wide-open position doesn't pull the governor arm to its stop.

Thoughts? It appears to have been this way for a while, but since I'm in there...

I wanted to ask the experts before I tear it apart.

Throttle pushed all the way counter-clockwise:

Throttle pushed all the way open to the stop on the quadrant and the governor lever pulled to its stop:

Royse · Feb 21, 2021

It does have a clamp bolt, but the throttle rod is notched for the
bolt to pass through. Unless the rod is worn out, I don't know how
the "lever assy" would spin around the rod very much at all.

hunkydory · Feb 22, 2021

(quoted from post at 19:21:45 02/21/21) It does have a clamp bolt, but the throttle rod is notched for the
bolt to pass through. Unless the rod is worn out, I don't know how
the "lever assy" would spin around the rod very much at all.

That is helpful, thank you!

I call is the "lever assy" because that's what the book calls it.

My set-up has me confused. (not difficult to do....

)

Is it normal for the governor rod to contact the block when closing the throttle? The old rod was deformed from people trying to force the throttle counter-clockwise:

which corresponds to this position on the quadrant:

Looking at the "lever assy" at the wide-open stop (the spring is long gone):

Thank you for your insight!

hunkydory · Feb 25, 2021

I'm having a hard time believing my throttle is right. It doesn't make sense that the hand throttle lever only uses ~5/8's of the quadrant on the dash.

The FO-4 manual says to make sure the governor lever hits its stop when the hand throttle is in the last notch of the quadrant. Is that all we care about? Not how low the hand throttle goes in the quadrant?

soaked · Feb 25, 2021

Hi Hunk, You are correct, your lever
assy is not clocked, or indexed properly
to your throttle control rod.
Here is one of my 8ns at full throttle

The lever assy is a whisker away from
touching the steering box.

At slowest idle setting, the rod to the
gov should not hit the block or the
valve cover

I only see one used lever assy on line.
No new ones.
Lots of hits for new throttle control
rods.
The angle of your handle to the stopper
arm up on the quadrant looks the same as
mine.

Something has twisted.

hunkydory · Feb 26, 2021

The angle of your handle to the stopper
arm up on the quadrant looks the same as
mine.

Something has twisted.

Thank you, Soaked! I'll be pulling it apart to see what's wrong with it.

hunkydory · Mar 6, 2021

Royse and soaked, thank you for your help!

I took the lever off the rod and found the notch in the rod was wallowed. Someone must have yanked the crap out of it in the past. One can only wonder why.

Keeping with the spirit I shimmed the space with a piece of beer can aluminum. :lol: Everything is nice and tight now.

Question: Does the spring (#9827) between the lever and a plate beneath a transmission bolt help with anything? Mine is long gone.

Thanks again.

Royse · Mar 6, 2021

That's the governor compensating spring.
As I understand it, it is to help keep the throttle lever from
moving when the governor compensates for engine load.
I've seen quite a few work fine without it.

soaked · Mar 6, 2021

Better empty another so you have a
spare! 😆

Caryc · Mar 7, 2021

I had a problem on my 8N. The throttle would not stay where I set it. This was due two a worn throttle plate and the ball in the throttle rod being worn.

Below you see a pic of old and new throttle plates. You see how worn the ridges are in the old plate compared to the new one.

The other pic shows the ball in the throttle rod worn just about flat. The ball can be replaced in the throttle rod. It's a 3/8" steel ball. You can pry it out and put a new one in. That ball is standard 3/8" steel sling shot ammo available in most sporting goods stores.

The spring you are talking about pushes the throttle rod down so the ball is snug against the throttle plate.

I had to order a new throttle plate and the throttle rod was cheap enough so I just replaced both parts.

jimtrs · Mar 7, 2021

The governor compensating spring is there to "compensate" against the governor spring, particularly in the higher rpm range.

As the throttle lever is moved towards higher rpm's, the tension on the governor spring increases to fight against the centrifugal force of the governor. This is what increase the throttle at the carburetor. As the governor spring tension increases, it tends to wanna pull the throttle lever back down to lower rpm's. The compensating spring "compensates" against this, along with the nothes and steel ball at the throttle plate, keeping your throttle lever where you put it.

wore out · Mar 7, 2021

(quoted from post at 11:36:26 03/07/21) The governor compensating spring is there to "compensate" against the governor spring, particularly in the higher rpm range.

As the throttle lever is moved towards higher rpm's, the tension on the governor spring increases to fight against the centrifugal force of the governor. This is what increase the throttle at the carburetor. As the governor spring tension increases, it tends to wanna pull the throttle lever back down to lower rpm's. The compensating spring "compensates" against this, along with the nothes and steel ball at the throttle plate, keeping your throttle lever where you put it.

Sounds good in theory, but in fact when the throttle lever is at maximum and the pull of the governor string is the strongest the "compensating spring" is at it's most relaxed point and not contributing much except due to the geometry of where the spring is hooked on the lever.

The later OHV models had a more complicated linkage system using the geometry of the linkage setup and mechanical advantage to make the compensating spring more effective, IMHO.

Caryc · Mar 7, 2021

Sorry, I got a little confused in my last post. I forgot he was talking about the Governor compensating spring and not the throttle rod tension spring.

hunkydory · Mar 9, 2021

Thanks, all! Great input as usual.

Lots of "spare aluminum" around here. No shortage in sight...

Thanks for that suggestion Cary. The ball on my lever is worn; I'll see about replacing it. It's been bad for a while because the arm itself has grooves from running across the quadrant mounting screws.

I'm going to hold off swapping out the quadrant and the throttle rod because they have character. That sweat/rust patina simply can't be bought.

hunkydory · Mar 28, 2021

Following up on the ball replacement. Why replace? Because I like fixing things. 8)

Cary was spot on about it being a 3/8" ball. I got a stainless one for less than $1 as a replacement.

Removing the old one is a bit tedious. Not quite as simple as prying it out. There's a significant chance of distorting the arm with too much force.

I gently heated the insides of the arm just before the ball's socket with a propane torch then slowly pried them open enough to release the ball. Dress the rough wear spots on the arm, drop a new ball in, pinch the arm in a vise, good as new.

Caryc · Mar 28, 2021

(quoted from post at 14:47:13 03/28/21) Following up on the ball replacement. Why replace? Because I like fixing things. 8)

Cary was spot on about it being a 3/8" ball. I got a stainless one for less than $1 as a replacement.

Removing the old one is a bit tedious. Not quite as simple as prying it out. There's a significant chance of distorting the arm with too much force.

I gently heated the insides of the arm just before the ball's socket with a propane torch then slowly pried them open enough to release the ball. Dress the rough wear spots on the arm, drop a new ball in, pinch the arm in a vise, good as new.

Did you see the little guy in the ball taking a picture of you?

It's a good thing he is only exposed from the waist up. I wonder if he's wearing pants?

Got to be careful when photographing stainless. :wink:

hunkydory · Mar 29, 2021

Did you see the little guy in the ball taking a picture of you?

It's a good thing he is only exposed from the waist up. I wonder if he's wearing pants?

Got to be careful when photographing stainless. :wink:

Word has it the excitement was almost overwhelming....

If you look at the picture closely it looks like a monkey wearing a black mask.

Fins/413 · Dec 28, 2021

Thanks Soaked I had the same issue with throttle position.
I took the air cleaner of to get reasonable access, took it loose and tightened it at the correct position. Everything works as it should the rod to the governor moves straight back and forth and I can set hand feed to the closed position. Somehow it got twisted, many thanks.

8N Throttle

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