Carb rebuild time or ?

[Barnaby]

Hello fellow forumers!

Can't seem to start Barnaby(1949 cub). Cleaned plugs and it started right up. Next time tried to start and he wouldn't go. Rolled it out of the garage after sitting for two weeks and it fired right up. Ran for 5 minutes . When I tried to restart it wouldn't go again. Any helpful ideas would help. Small gas puddle from leak at carb. Gas drips out of bottom of carb.

Thanks All

[Eugene]

Fuel leak most likely debris stuck in carburetor needle valve.

No restart, check for fire at spark plugs.

I'm one for a complete engine tune up starting with compression tests.

[Glen]

When I tried to restart it wouldn't go again. Any helpful ideas would help. Small gas puddle from leak at carb. Gas drips out of bottom of carb.

Hi,
They have said on here that it's normal for gas to drip out the drip hole on the bottom of the carburetor after trying to start the engine, and it won't start.
The engine sucks gas up the updraft carb, and when you stop cranking the engine, the gas runs back down, and drips out the drip hole.
The dripping should stop in 2 minutes or so after you stop cranking the engine.
If gas drip all the time from the carb, it needs repair. It could be what Eugene said above, or the float level could be too high, and needs setting to the spec in the Cub service manual.
Or the needle and seat could be damaged, or worn out, and need replacing.
If it drips all the time, I would start with cleaning the needle and seat, and check the float height while it is apart. I can send you info about repairing the carb, if you need it.
If the Cub has the IH carb, and you take it apart, pull the halves straight apart several inches. There is a small idle tube that screws into the top half of the carb, it can break if you twist the halves, or don't pull them straight apart.
Hi from another person in Wa.

[Barnaby]

Thanks from Camano. I'll take off the carb and clean first and look for debris. Please any info would help.It also seems to foul plugs.

Tune up new parts or clean and gap. What is compression range?

[Glen]

A 1949 Cub came with a magneto. Some Cubs were changed to a Battery Ignition unit.
If the engine quit running, the spark could have quit.
I would test the power of the spark the magneto is making.
Be sure the Cub doesn't roll while doing the spark test.

Remove the ignition wire from the center post on the distributor cap, and hold the wire by the insulation, with the metal end about 1/4" from bare metal of the engine block.
Be sure the transmission is in neutral, turn the ignition switch to on, and run the starter.
The spark should jump the 1/4" gap, and be blue or white. A yellow spark is weak, and needs improving.
The engine may not run, or run right, with a yellow spark.
Do the test in a building, or not in bright light, so you can see the spark well.
The battery should be fully charged for the spark test. Charge the battery if necessary.
A low output charger is better, it may take several hours to charge it.
If the spark is weak, or no spark, the ignition points may have corroded when the Cub was sitting.
The points may need filing or replacing. They get burned with use.
There are pictures of the points and condenser, inside the magneto in the 1949 Cub operator's manual on here. The points need the right gap also, .013" for a magneto.
The condenser or coil may have quit.
It is sort of common for the old original Cub coils to quit. Some of them work when cold, then quit when warm, then work again when the engine is cold.
The ignition timing can be checked with a timing light when the engine is running.
The Cub service manual says Cubs before serial number 192113, which was made during 1955, should have 107 lbs of compression at 240 RPM.
That is probably for a new engine, some less is ok. They have said on here that 90 or 100 lbs is ok.
I sent you a PM.

[Barnaby]

Well... Barnaby might be a little sick. Great bright blue spark at each plug. Compression #1 115 #2 115 #3 70 #4 110. Plug hole 3 is wet and black. Would you reccomend to do one valve or full valve job? Thanks

[tst]

how do you know its a valve ? use a leakdown tester to determine which valve or cylinderis leaking, or if you can put air in the cylinder see where it leaks out, ever adjust the valves ? if one is not closing can cause low compression

[Barnaby]

Adjusted valves 3 years ago. How does one do a leak down test?

[Glen]

Hi,
Thanks for saying the engine has spark, and what the compression is.
You didn't say if the engine runs again, or not.

If the engine has black oil coming from a spark plug hole, it may have stuck, or wornout, piston rings.
The Cub has a valve in the block engine. They have said on here that oil burning usually isn't caused by the valves.
They have said if the engine is smoking, or has low compression, to put Seafoam oil additive in the engine oil.
They sell it at auto parts stores.
Piston rings commonly get stuck, and then the engine can smoke, or have low compression.
It could help the compression, if the rings are stuck, and the Seafoam loosens them.
Make the engine work doing something when using the additive, so it warms up.
I have read on here of people having good results after using the oil additive.

One of the experts on here said to use the additive for 2 oil change periods.
The 1949 Cub operator's manual says to change the oil every 120 hours of use.
If the piston rings are wornout, the seafoam won't help much.

I would use the oil additive, it's much easier than taking the engine apart.
I have used another brand of oil additive when needed.
I haven't used the Seafoam, but have read people's posts about it on here.
Follow whatever directions there are on the Seafoam package.

[Eugene]

I currently recommend Seafoam because it's available in most auto parts stores.

I really liked Rislone High Mileage Engine Cleaner Treatment, but it's not available in my local auto parts stores.

[Barnaby]

I did get Barnaby to start and run. I'll try seafoam.

[Barnaby]

Well good news. I followed some instructions and it starts easier. I cleaned tightened and adjusted the carb. I used a half of a can of seafoam in the tank. Still smokes a bit but we`ll see after time. Thanks for good advice.