Red cub vs yellow cub round 2

[Shadow_storm56]

Trying again... hopefully don't lose my post again. I have a later model red cub with the under belly exhaust and a yellow/white cub. Both had engine rebuilds at one point and the red one although it's supposed to have less hp than the yellow it has so much more I am realizing the yellow one has issues. Like if the red has 12hp the yellow may have 7.....

I compared the normal things like compression, I replaced both carbs so they both have the same carb... both have same compression in front 2 cylinders atleast but driving the yellow one down hill it feels like it has low compression so it makes no sense. I checked the plugs to and both show they are running a good mix as well so I'm confused.

Maybe one cylinder has weak compression and it's making it pull less vaccume overall so less fuel in? So either I have the red one tuned so perfectly it's got more than normal hp by alot... which seems unlikely or the yellow one has a severe issue I'm not thinking of.... help? Plzz

[Don McCombs]

Have you checked valve adjustment?

[Shadow_storm56]

Have you checked valve adjustment?

No but shouldn't compression be bad if the valves are adjusted wrong? I mentioned the yellow one runs really hot too right?

[Cubfriend]

Running really hot could be a too lean condition. Make sure it’s getting enough fuel.

[Shadow_storm56]

Running really hot could be a too lean condition. Make sure it’s getting enough fuel.

Going by the plugs it was running just fine, I could make it richer though but like it runs 20-25c hotter than the red one and it's under much less load.

[Gary Dotson]

Check ignition timing, retarded timing will cause both issues. If you don’t have a timing light, borrow one.

[SamsFarm]

B4V6X7 Interesting zip code, where is that at?

[Jim Becker]

Nova Scotia, Canada.

[tst]

you did not say what your compression readings are ? also are the advance weights working in your distributor?

[Shadow_storm56]

I did not know there were advance weights, also the yellow tractor read a compression of 105. Red one was about the same although the starter on that one is weak and slow sooo

[DZG]

My 48 will get a bunch of moisture under the dist cap sometimrs and will run like its on its deathbed

[inairam]

I would adjust the valves and the timing and the governor to carb linkage. If you have a tach or get an induction tach (~20 bucks on amazon) and see what the RPMs are at idle and full throttle for both cubs. Maybe the governor itself ( not just linkage) needs some adjustments but do that very last. It is also never the governor. I would also change the screen in the top of the fuel bowl, and clean the oil bowl in the air filter, check for air leaks between the cab and the manifold by spraying start fluid on the outside and listen for an RPM change. These are little things but if you are going back and forth between tractors they become noticable. I have also been having problems with IH and no names points and condensers. I started using NAPA ( I do not know where to get the equivalent in Canada)

My signature is "When you only have 9 horsepower you need to know the names of all of the ponies!" a difference in HP/performance between the cubs can be a lot of little things that are off just a little. Doing a complete comprehensive tune-up of all systems may help iron this out.

[Pap]

My 48 will get a bunch of moisture under the dist cap sometimrs and will run like its on its deathbed

WD-40 is good for removal of moisture.
I had a truck that would get water under the distributor cap. It sometimes would be soaking in moisture and WD-40 would fit it.

[Glen]

I did not know there were advance weights

Hi,
There are spark advance weights in the Battery Ignition unit.

Below is what it says about it in the 1955 Cub brochure.

"Battery Ignition has automatic spark advance to assure smooth running at all engine speeds and exceptional lugging ability. Coil is oil sealed to keep out moisture."

Below is a page from the Cub parts manual showing the IH distributor, the weights are number 14 in the pic.
The weights advance the spark different amounts at different engine speeds.
At full speed, the spark is advanced to 16 degrees before TDC, that makes the engine have more power than without the spark advanced.

http://www.farmallcub.info/manuals/cub_ ... 012-28.jpg

You can see if the advance mechanism is working freely by removing the distributor cap, and turning the rotor back and forth. The rotor should turn a slight amount.
The shaft that turns can get tight from no oiling.
If the shaft is stuck the advance won't work, then the engine won't have as much power as it should.

Below is a page showing the distributor, oil in the center of the shaft with light motor oil, and turn the shaft back and forth to work oil in the shaft. Use the rotor to turn the shaft both ways.

http://farmallcub.com/rudi_cub/www.clea ... age-12.jpg

Cam number 15 in the parts pic turns a slight amount on shaft number 18, the end of the rotor might turn less than 1/4".

If the shaft is stuck and won't loosen, you may need to take the distributor off, and use penetrating oil to loosen the shaft.
Be careful removing the whole Battery Ignition unit, if you tip the front of it down, the drive can slide out on the floor.

[Shadow_storm56]

I did not know there were advance weights

Hi,
There are spark advance weights in the Battery Ignition unit.

Below is what it says about it in the 1955 Cub brochure.

"Battery Ignition has automatic spark advance to assure smooth running at all engine speeds and exceptional lugging ability. Coil is oil sealed to keep out moisture."

Below is a page from the Cub parts manual showing the IH distributor, the weights are number 14 in the pic.
The weights advance the spark different amounts at different engine speeds.
At full speed, the spark is advanced to 16 degrees before TDC, that makes the engine have more power than without the spark advanced.

http://www.farmallcub.info/manuals/cub_ ... 012-28.jpg

You can see if the advance mechanism is working freely by removing the distributor cap, and turning the rotor back and forth. The rotor should turn a slight amount.
The shaft that turns can get tight from no oiling.
If the shaft is stuck the advance won't work, then the engine won't have as much power as it should.

Below is a page showing the distributor, oil in the center of the shaft with light motor oil, and turn the shaft back and forth to work oil in the shaft. Use the rotor to turn the shaft both ways.

http://farmallcub.com/rudi_cub/www.clea ... age-12.jpg

Cam number 15 in the parts pic turns a slight amount on shaft number 18, the end of the rotor might turn less than 1/4".

If the shaft is stuck and won't loosen, you may need to take the distributor off, and use penetrating oil to loosen the shaft.
Be careful removing the whole Battery Ignition unit, if you tip the front of it down, the drive can slide out on the floor.

It certainly sounds like the symptom but I was investigating the distributor before reading this and just happened to turn the rotor which it does turn the little bit like you said although your talking about a 1955 cub I think this ones 1974, the one that's not working right atleast. I finished checking compression and all 4 cylinders are good there. It's starts and runs far too smooth to think it's actually out of time overall but I may investigate this just incase it's moving but not enough. The red one will lug right down and keep going, this one does a bit but much less and it gets so hot.