Final Idle Adjustments Woes---

Picked up a 49 8N a few months back. Front mount Distributor, 6 volt, new battery, Negative ground. Tractor was used very little the last 10 years.

Starts up on 2nd crank with 1 pull on the choke, hot or cold (needed to be choked when hot. Needed to keep choking her for a few minutes until she warmed up and ran at HIGH Idle. Have 25-28 lbs. oil pressure hot or cold.

Engine falters when throttling from low speed to high speed, when cold or during hard workouts plowing snow, with or without load. Throttle arm had no engine response on lower 1/5 of quadrant from excessive wear/improper adjustment.

Here is what I have done since the snow stopped falling.

Replaced plug wires, put in new plugs gapped at .025, new points gapped at .015, new condensor, distributor cap, reset timing,double checked firing order.

All battery connections, wire connections cleaned "brite and tite".

Replaced all fuel filters, cleaned out sediment bowl. Replace all fluids. Found no thermostat in upper radiator hose (new one is going in tonite).

Rebuilt throttle linkage with new quadrant, new steel ball, new compression spring, added governor compensation spring (was not on linkage). Straightened out bent long throttle arm to governor. Adjusted the high speed setting on governor arm which is connected to long throttle arm.

I now found that I had less (but some)stumbling of the engine when I throttled from the "still high idling" engine to the high speed notch on my quadrant. The engine starts as easily as it did before I began doing these "tweekums" and does not need to be choked after engine warms up.

At this point is where I FIRST started to check on carburetur adjustments. I found that the main needle was turned out CCW 6 full turns. I turned the main needle in until it stopped and backed off 1 1/2 turns CCW for starters.

My second move was turning in CW the side pointing idle mixture screw. This screw was turned out 3 full turns, but when I turned it in expecting the engine to stumble, nothing happened. I closed it all the way and backed it off 1 full turn, with no noticeable change in engine RPM"s.

My third move was to turn the "behind the carb" idle speed adjustment CCW until the engine did idle down to a slow 400-500 RPM. I moved the throttle quickly from idle to high speed and the hesitation/stumbling was gone.

PROBLEM--after returning the throttle lever to the idle position on the lower end of the quadrant, the engine was now idling as fast as it was before I adjusted the idle speed screw. I can take my finger and push this screw down slightly and the engine idles down to where you can almost count the revolutions of the engine.

While holding this screw down with my finger, I try to adjust the side pointing Idle Mixture Screw (for Maximum Idle RPM"s) in to where the engine should stumble and I still get NO response on engine speed. I cant seem to get any change in the speed of the engine to allow me to set the MAXIMUM IDLE RPM"s. My hearing is bad, but not that bad.

The short rod that goes from the carb to the governor seems to be straight and non-binding. I have been spraying solvent on the governor arms for a day now, thinking there might be some restriction/hangup from paint that had been applied years ago. The idle speed screw and linkage appear to be working freely.

Any suggestions on getting the getting IDLE Mixture screw and the Idle Screw functioning so I can set the Maximum Idle RPM"s and reduce the idle speed correctly?

Thanks guys---Tim

I really appreciate all responses, but maybe I need to clear up some things from my original post so that I don't get confused.

Turning a screw in= turning it CW (clockwise)
Turning a screw out= turning it CCW (counter CW)

I write--"main needle" referring to the BIG power adjustment screw at the front of the carb, closest to the front of the engine.

I write--"side pointing idle mixture screw" referring to the adjustment screw that faces the guy doing the adjustment.

I write--the "behind the carb" idle speed adjustment screw referring to the screw closest to the engine.

This info is meant only to clear up what might be some confusion as to what/how I have done to get this issue fixed--I apologize if I am not being clear enough---Tim

"IN"... (CW) is "LEAN"

"OUT"... (CCW) is "RICH"

2.) Clogged passages or a bad gasket between the upper and lower halves of the carb will cause the idle circuit not to function.

Yes, adjust idlemix for MAXIMUM idle rpms NOT SMOOTHEST idle.

Yes, idlemix is only effective at SLOW idle. (thats why they call it idle?)

YES, clogged passages or bad gasket will cause the idle circuit to NOT function.

Much to the dismay of gov't smog bureaucrats, each engine/carb combination must have carb-tweek'ums.

Just for reference, my eazy starting 6-volt '52-8N idles at SLOOOooow 400rpms per proofmeter and side-pointing idlemix is 1/4-turn and down-pointing mainjet is 2-turns. Yours will be slightly different, but should be close..... ...Dell

I posted (correctly) that it operates backwards then typed out (incorrectly) how a more conventional mixture screw operates!

I am a bit stubborn and still don't want to believe there is a problem inside of the carb, so I am going to try 1 thing that has not been mentioned yet---

The tractor idles down, but after speeding up the throttle doesn't hold that slow RPM adjustment, so I am going to take a peek inside the governor and check to see if the thrust balls have any flat spots on them and if so, replace with new ones. Hopefully the races will not need to be replaced too.

If that doesn't fix the problem, I will have to give in and take the carb off and repair/rebuild what needs to be done-----I will let you know what the results are---Tim