Sometimes it starts sometimes it doesn't

[Luke470]

Hi All,

Have a 61 cub. When I go to start it I turn the fuel on at the sediment bowel - about 2 turns - I then choke it, turn on the ignition and pull the starter. Sometimes it fires but sometimes it just cranks. If I leave the gas on too long it will start dripping out the drain on the carb. I'm guessing a good cleaning of the carb would probably do wonders but just wanted to check to see if anyone else had any advice.

Thanks!

[Eugene]

When I go to start it I turn the fuel on at the sediment bowel - about 2 turns.

Turn the shut off screw out until it stops. May take 3 or 4 or more full revolutions, out.

I then choke it, turn on the ignition and pull the starter. Sometimes it fires but sometimes it just cranks.

Perhaps the sediment bowl valve is only partially open, restricting, slowing down, the fuel flow.

Starting my Cub, open the fuel valve, check engine oil, shake hands with shifter, attempt to start. Procedure takes a minute or so. Enough time for the fuel to fill the carburetor and fuel line.

If I leave the gas on too long it will start dripping out the drain on the carb. I'm guessing a good cleaning of the carb would probably do wonders.

Wouldn't hurt.

[Lurker Carl]

Maybe you only need to choke it momentarily as the starter turns the engine, dripping gas indicates flooding. Otherwise, it's tune-up time.

Most "carburetor problems" are resolved with a full tune up. Measure/adjust valve lash and look for valves sticking open. Check the fuel tank for water, rust, debris; use fresh fuel. Don't fiddle with the carburetor until the ignition system is up to snuff and you discover trash in the fuel.

[twotone]

I never have to choke my Cubs in warm weather to get them started.

[Bigdog]

I never just open the sediment bowl valve just partially. I always open it fully until it back seats.

[bythepond88]

Try starting it with no choke at first, and then, if she doesn't catch on the first rev or two, add choke. Since I started that sequence, Eddie almost always fires up. Only time she doesn't is when its bitter cold, and even then it's only once or twice that she has refused.

Wish I could remember who first posted that suggestion so I could give proper credit.

[Matt Kirsch]

On the choke: Every tractor is a little different in how much choke it wants to start and how it is applied. Set it and forget it generally doesn't work, and usually floods the engine, causing a no-start and gas dripping from the carburetor.

First experiment: Open the fuel valve all the way, and wait. No crank. No choke. Does fuel start dripping? If so you need to do some carburetor work. The main needle is leaking so odds are things are gummed up.

Second experiment: If no dripping after experiment #1, try cranking without the choke. You may be pleasantly surprised.

Third experiment: If no start with cranking in experiment #2, try "blipping" the choke. Just a quick hit. Keep giving the engine blips of choke until it fires, and keep your hand on the choke as it first begins to run. Add if it starts to die, let off as it starts to run better.

[Luke470]

Thanks for all the info and all the tips.

I should also mention that when it does start it runs like a champ.

[Eugene]

Starting my standard Cub with IH carburetor is as previously described. Not a lot of choke. In cold weather I have to feather the choke a bit until the engine runs smooth.

Zenith carburetor on the 154 is a different story. Takes quite a bit of choke in cold weather and then a bit of choke feathering until the engine smooths out. Warm weather still takes a choke for the first engine revolution or two.

[nwfan1]

I've had a loose wire on the ignition switch that would make my 55 do that. Maybe check your switch- is it always turning the ignition on? I think you should see a slight discharge on the amp meter when the ignition is truly on.

[Bus Driver]

"I think you should see a slight discharge on the amp meter when the ignition is truly on." This is true if the ignition points are closed, as they are most of the time. But it is possible that the engine will stop with the points open in which case the ammeter will not show a reading.