fowling plugs

[walki'nstick]

walki'nstick here--I'm new--I pulled my dad's old "49" cub out of the barn abt. a year ago and have been working on it--off and on-- since then. I have rebuilt the carb., all new ignition and fresh fluids. It will start fine, even when dead cold in the shop. No blue oil smoke, very little smoke at all. If I run it for any amount of time(half hour or so) it has fowled out the plugs to the point of not restarting. I'm sure someone out there can tell me what to look at next. Thanks in advance for any help.

[Eugene]

What color is the fouling on the spark plugs?

My first guess is that the spark plugs are being fouled by engine oil passing the piston rings. Piston rings wear out or get plugged.

Suggest SeaFoam in the engine oil and fuel tank. It's a try to see if you can loosen up piston rings. Probably won't work, but a cheap try.

You could try hotter spark plugs and a heavier weight engine oil. These are only temporary fixes.

[Jim Becker]

What heat range are the spark plugs? Too cold will foul with a half hour of idling. Are the plug wires solid core or resistor wires? Resistor wires combined with a magneto (if so equipped) is a combination for ignition problems.

[BigBill]

The float level is too high or the choke isn't fully opening. I've seen the choke hang a tad closed with no smoke but it's running sluggish. Is the needle and seat leaking? Shut off the engine and leave the pedcock open on the gas tank. Pull the house off the carb to see if it drips.

No heavier oil in the winter.

If the top of the float is flat the flat gets parallel to the bowl face surface.

If the float is round set the seam where the float welded horizontal, again parallel to the bowl face surface.

Check it by holding the carb inside down.

[cub.bub]

Welcome! I too had this problem and tried the Sea Foam in the fuel and oil, after the second tank my "smoking" reduced to almost nothing, and it responds better. I also changed to D-21 plugs which helped too.
You'll get plenty of help here.....keep us updated.
bruce.

[Bigdog]

How long had the tractor been sitting? It could have some rings still sticking. I agree with Jim - check the plug wires. If they are resistor wires and you have a magneto you will get a poor spark.

[walki'nstick]

walki'nstick here--Thanks for all of the feed back--hey Bigdog, I find that a little duct tape works well with that hammer! The tractor has been basicly inactive for abt. 15 years. Just started, usually, spring and fall. Sometimes I would run it around the property, maybe 10 min., hasn't been under any real load conditions. Has Fresh gas with a little sta-bil and some sea foam. The ignition is new from the points to the plugs. The wires are not the resistor type; solid wire. And I do have a J4 magneto. BigBill I have thought abt. float adj. Have not checked yet. I recently changed oil, new oil is 10w30. cub.bub, I have added sea foam to the gas but not the oil, I'll do that. The new plugs are autolite 386, just went to the local NAPA and ask for the appropriate plug. What brand are your D-21s.

[Don McCombs]

What brand are your D-21s.

Champions

[Barnyard]

The tractor has been basicly inactive for abt. 15 years. Just started,

Did you prime the oil pump. If not, make sure you do before running it anymore.

[walki'nstick]

walki'nstick here--I think the cub is cured! Have used sea foam in the plug holes, and let that sit overnight. Put sea foam in the oil(8oz.) The rest of the can of sea foam, in abt. 2-1/2 gal. of mid grade gasoline. I have ran the tractor 2-1/2 hours(I timed it), pulling the plugs and cleaning them twice. The last time the plugs came out they were not fowled very bad at all. I believe that with more run time, some of that will clear up. Since it starts good in this cold weather, I won't go to the hotter plugs yet as someone suggested.