cub 184 power issue

hey guys,my friend's 1979 ih cub 184 has been sitting for about a year,it has a factory rebuilt carburetor and the fuel tank has been flushed,but it still is lacking the power it once had,we were thinking it could be the governor causing this problem.it starts up great and sound good,but when you put it in gear it loses a lot of power,and sort of jumps up and down,and won't keep a steady rpm.any help appreciated.thanks.Rock

Has anyone tried adjusting the carburetor? Most need to be adjusted for the particular engine they're on.

1. Take a thin piece of thin wire and clean out the main jet. Follow with spray carb cleaner and compressed air.

2. Check/set valve lash

3. Set the governor pre-load per the procedure in the service manual

4. Check condition/gap/replace spark plugs, plug wires, and points as needed

I will 2X that. Idle air mix screw, gently turn screw in till it just stops then back it out a little more than one complete revolution. The main jet turn it till seated and then turn it out one and a half turns. That is where you start on your adjustments. The main jet may need up to two turns out depending on the engine. CAUTION. Some carbs have a set metering jet for the run part of your carb and cannot be adjusted. Thus there will be NO main jet needle. That is how my 1977 CUB is set up. Just for s☆☆☆☆☆☆ giggles please drain all of the gas out and then buy a gallon of Hi-Test. Give it a try it may surprise you. Let us see what the others say.

If it ran good before I would try a good dose of sea foam. Randy

The jumping is likely a misfire. Check the spark quality at the plug end of each wire. It should jump 1/4" to ground, blue hot spark. Replace the plugs just to say you did. If it has points, check the gap and check the distributor shaft for side play. A worn distributor or improperly gaped points will do just what you are describing. Check for vacuum leaks.

Check the fuel flow through the carb. Pull the drain plug on the bottom of the carb, it should have a good continuous flow, not slow to a drip or stop flowing. If the main jet is adjustable, it may be too lean, especially if a partial choke helps it run better.

An easy test for the governor, with the engine off, throttle set for fast, the carb throttle plate should be spring loaded in the full open position. Start the engine, set the throttle for idle, suddenly push the throttle lever to full speed, watch the carb throttle plate. It should go full open, then modulate back as the engine speed comes up. If these things are happening, the governor is doing what it should. Surging is usually a symptom of a too lean mixture.

If the jumping persists, run a compression test. Should have 90+ PSI and all cylinders be relatively close to the same.
If any are low look the valve train over, check for stuck valves, tight valve lash, broken springs, bent pushrods, rockers not moving to fully open a valve. If all checks good, could be a leaking valve, blown gasket between cylinders.

hey guys,we only adjusted the carb a half turn,so like you said it probably needs more adjusting.also the igntion system has been recently replaced,but i know that doesn't mean anything,so we will check for spark.thanks.rock

Did you cross the plug wires?

"Jumps up and down"? Could it have moisture inside the distributor cap, or a crack? Start it up after dark and see if any plug wires are sparking.
Loss of power in Cubs is often caused by poor valve sealing. If all else fails it may be time for a compression test.

leroy,we haven't really messed with the spark yet,but we are going to do some trial and error,thanks,rock

Is the "jumping up and down" by chance taking place as the clutch is let out? I agree with carburetor cleaning and adjusting. Was the tank cleaned and flushed before or after the jumping up and down? I'll bet not until after, so your carburetor was fed a good dose of carburetor plug up just before it started running poorly.

hi,we flushed the tank a couple days before installing the carburator,thanks,rock