8n wont idel down

[Money Pit]

8n side mount distributor. turn the throttl down all the way but engine keeps running about half of full speed. tractor is 2 hours aay wont be bale to check it until next weekend. hoping for some ideas on what top look for. thanks .

 

[kossuth]

(quoted from post at 10:26:00 05/17/21) 8n side mount distributor. turn the throttl down all the way but engine keeps running about half of full speed. tractor is 2 hours aay wont be bale to check it until next weekend. hoping for some ideas on what top look for. thanks .

eed more info. Wont idle down as in engine basically runs away or will stall out when you attempt to idle it down. Two very different issues.

 

[Jim L WA]

Keeps running at about half full speed doesn't sound like it's dying to me. The throttle plate in the carburetor is controlled by the governor. The governor is controlled by engine speed of course but also by the linkage from your throttle lever to the governor. First thing I would do is remove the link from the governor to the carburetor, start the tractor and with your fingers on the carb. throttle see if it will slow down to an idle. If so then it's not the carburetor. Put that link back on and remove the link from the throttle lever at the governor, start it up and see if you can idle it down using the lever on the governor that you removed the link from. If it will idle down, then I would check for bent or binding linkage. If it won't idle down then it's time to remove the governor and overhaul it.

 

[Royse]

In the linkage on the back side of your carb is the adjusting screw for idle speed.
Push on the head of the screw with your finger. Does it idle down then?
If you can't push it and the screw is touching, it may need an adjustment.
If you can't push it and the screw is not touching, there's a possibility
that the screws holding the throttle plate have come loose and it's binding.

 

[TheOldHokie]

(quoted from post at 21:55:25 05/17/21) In the linkage on the back side of your carb is the adjusting screw for idle speed.
Push on the head of the screw with your finger. Does it idle down then?
If you can't push it and the screw is touching, it may need an adjustment.
If you can't push it and the screw is not touching, there's a possibility
that the screws holding the throttle plate have come loose and it's binding.

You were reading my mind with that throttle plate idea.....

TOH

 

[Smokeonthewater]

(quoted from post at 13:26:00 05/17/21) 8n side mount distributor. turn the throttl down all the way but engine keeps running about half of full speed. tractor is 2 hours aay wont be bale to check it until next weekend. hoping for some ideas on what top look for. thanks .

Need some background info... has it been this way as long as you've had it or was it normal and just suddenly or gradually got this way?

What have you tried so far already?

 

[Money Pit]

thanks for all the replys.

wont idle down: i move the throttle to the lowest / slowest position yet the engine keeps running about half speed. not a ne wproblem just getting tired of dealing with it. sometimes the engine will eventually idle down on its own. i can manually move the governer linkage and get a slower idle but once i let go it revs back up. governer works when under a load; it adds more throttle to try to keep a constant engine speed.

hope the added info helps.

 

[R Geiger]

(quoted from post at 08:32:03 05/18/21) thanks for all the replys.

wont idle down: i move the throttle to the lowest / slowest position yet the engine keeps running about half speed. not a ne wproblem just getting tired of dealing with it. sometimes the engine will eventually idle down on its own. i can manually move the governer linkage and get a slower idle but once i let go it revs back up. governer works when under a load; it adds more throttle to try to keep a constant engine speed.

hope the added info helps.

I would open up the governor and see what it looks like. Or adjust as per the manual.

 

[Smokeonthewater]

(quoted from post at 10:54:21 05/18/21)
I would open up the governor and see what it looks like. Or adjust as per the manual.

Yep sounds like cleaning, and adjusting the governor and linkage is in your future....

 

[Ed S.]

My 1950 frontmount has gradually lost its ability to idle over the years - once it warms up, it "idles" at what seems to be close to full throttle. I can manually pull the governor linkage and slow it down. I've never been able to get it to idle at a lazy 400 RPM, but was definitely a lot slower back in 2009 when I 'restored' the tractor (which did not include a governor overhaul).

I pulled the governor this morning, and sure enough, the balls are flat-spotted as is the flat lower race. I was just putting it back together when we stopped for lunch, so hopefully I'll report back that it runs properly after it's all back together.

es

 

[Ed S.]

Here's what I found inside the governor:

I got it back together, and it was still running away at idle. I ended up lengthening the throttle-to-carb rod as long as it would go and repositioning the spring at the base of the throttle quadrant shaft (where the rod to the carb connects) so it had a better pull on the rod. Also loosened the outer shaft spring on the governor itself - it's pretty much hanging loose at idle.

Still won't idle all the way down without a little push. Not sure why it's hanging up, as it doesn't feel tight or anything.

At any rate, it's idling down to a sub-frantic speed now, and I'm happy with that.

es

 

[Money Pit]

OK; got to spend some time with it this weekend.

Without the engine running the throttle is at rest on the stop for the idle adjust.

Start it up and it goes to high idle. Seems like it gets worse higher once it warms up.

Can get it to a slow idle by pushing the carb to governer rod forward. Once released the idle climbs back up.

Can get it to a lower rpm when it has a load on it. Governer seems to act normal increasing throttle responding to a heavier engine load.

Tall arm on the governer has a lot of play in it I can rock it towards and away from the block quite a bit.

 

[1658Dutch]

I had the same problem. 1950 8n, Serial#267611. I had multiple problems simultaneously. Ignition switch was bad and replaced. Insulator (thick piece of paper) inside distributor that connects copper strip from condenser to bolt/wire going outside to coil, was worn and grounding out and replaced with household electrical wiring sheathing. When the tractor did start up after replacing fouled spark plugs (it doesn't take long to permanently foul plugs), carburetor could not be controlled, and the choke had to be pulled to get it to run. The back idle screw was changed to zeroed out; the idle fuel mix screw was changed to fully closed and the main jet screw was left as it was, open one and half turns for it to run. The float was stuck so fuel drizzled out of the air cleaner rubber tube. I took the TSX33 carburetor off and put on an OEM fully rebuilt TSX241B. TSX241B is the best factory version carburetor to put on. The TSX33 didn't even belong to my serial number version anyway. Keep in mind, timing, points, condenser, spark, governor, compression, distributor, coil, battery, fuel quality and flow, air filter flow, wiring, etc. had all been checked prior to the carburetor change out. With the new carburetor on, the back idle screw had to be zeroed out, the idle fuel mix screw was fully closed, the main jet screw was opened four turns and the choke was held open three quarters for successful engine operation. RPM range on tachometer set for 2P:1r (2 pulse per 1 revolution attached to any a sparkplug wire) would give me a perfect 2200 RPM at full throttle but no less than 950 RPM. And with that, the throttle lever could not go to the bottom of the quadrant. It had to stay three clicks higher. Meaning, if something wasn't wrong somewhere else, I could have just dropped the throttle lever to the bottom of the quadrant, I would have achieved 400-500 RPM. With the idle fuel mix screw closed, it meant I was getting air from somewhere else. I tested three times with WD40 and one time with map gas all around the intake manifold where it meets the engine block, the carburetor to intake manifold gasket and all over the new carburetor while the engine was running at best idle and warmed-up. In practice, this will cause the idle to jump higher momentarily when you find/spray the hole in the gasket or manifold causing unwanted vacuum leak. I changed tactics and used an aerosol carburetor cleaner with straw attached to the can to repeat the process of spraying everything. The hope was that the cleaner would clean way some sludge and raise the idle momentarily. I got results from this test, but not what I expected. Not every time but 80% of the time with heavy blasts of carb cleaner on the top of the intake manifold where it meets the engine block where it supports cylinders one and two, the engine bogged down and stumbled momentarily (it didn't jump). I had a bad manifold gasket that was supplying air to my fuel mixture, thus neutralizing any use of my idle fuel mixture screw. The reason the carb cleaner didn't jump-raise my idle was my idle fuel mixture screw was fully closed and I was adding more fuel at the hole in the gasket and with not enough air the engine instead bogged down and stumbled. In conclusion, try using aerosol carb cleaner heavily around the intake manifold to engine gasket repeatedly and look for engine idle bogging or jumping. When everything else is/tested good but can't get a lower idle, it is a vacuum issue and only four locations to test: intake/exhaust manifold gasket, cracks in manifold causing intake/exhaust crossover, carb to manifold gasket and body of carb.

 

[jimtrs]

Read up on governor spring adjustment

 

[Abbby]

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This post was edited by Abbby on 02/18/2023 at 04:47 am.