Leak from drain tube when motor is stopped from running.

hi Patricia.
Overview Toilets haven't changed much in the last 80 years. After a flush, water still fills a tank, lifting a float that shuts off the water when it reaches a certain level. A lever still opens a flapper to cause the flush, falling back into place when the water level drops. So it's no surprise (nor any consolation) that we face the same flush problems today that our grandparents did. Sometimes the flush is too wimpy, sometimes the toilet keeps running, and sometimes the bowl doesn't refill.
Our ace plumbing consultant has a simple four-step strategy to solve 95 percent of these problems. You can complete the first three steps in five minutes. That'll solve most problems. The fourth step is usually easy too, but not always. More on this later. These steps work for most toilets but not for pressure-assist models.
Check the fill tube

Overflow tube problem

Push the fill tube firmly onto the fill valve. Make sure the fill tube sends water into the overflow tube.Remove the tank lid and find the fill tube. It's a small flexible tube that runs from the fill valve to the overflow tube. While the tank refills, this tube squirts enough water down the overflow tube to refill the bowl after the completed flush. If this tube falls off or the water stream misses the overflow tube, the bowl won't fill and your next flush will be wimpy (that is, won't develop a strong siphon). Reattach the fill tube and make sure it perches about 1 in. above the rim of the overflow tube. Flush the toilet and watch the water stream to make sure it goes down the overflow tube.
Adjust the fill height

Check the float

Adjust the float to set the water level. Pinch the clip and slide the float up or down on the rod. Keep adjusting the float until the water shuts off at the proper level.The water level in the tank is controlled by an adjustable float. A float that's set too low produces a weak flush; if it's set too high, water spills into the overflow tube and the fill valve won't shut off. The toilet keeps running. Look for the fill level mark on the inside back of the tank and mark it on the overflow tube so you can see it more easily. If you can't find it, measure down about 1 in. on the overflow tube and make a mark. Then flush the toilet and see if the water reaches and stops at that mark. If not and the toilet keeps running, adjust the float up or down. If you have an old toilet, you'll have to bend the brass rod that connects to the float ball to make adjustments. But with newer toilets you usually turn a screw or slide a clip along a rod. Flush the toilet after each adjustment.
Also make sure that the water level is at least an inch below the C-L (critical level) marked on the fill valve. You can adjust the height of many valves to raise or lower the C-L.
Occasionally the fill valve simply won't shut off, which means that it's defective. If so, turn the water supply off at the shutoff under the tank. Buy a replacement valve (sold at hardware stores and home centers). You don't have to match the old one; many, like the one shown, fit most toilets. It's a 15-minute change-out.
Adjust the flush handle/flapper chain

Flapper chain fix

Adjust the chain to leave a little slack with the flapper closed. Then cut off the excess, leaving about an inch.A chain that's too short or tangled won't allow the flapper to close and water will continue to leak into the bowl. This causes the fill valve to cycle on and off to refill the tank. A chain that's too long, or a flush rod that hits the the tank lid, won't open the flapper wide enough to stay open for the full flush. You'll find yourself having to hold the lever to complete a good flush.
To avoid these problems, adjust the linkage in the chain to leave only a slight bit of slack when closed. Cut the chain at the rod to leave only about an inch extra to reduce the potential for tangles. Then put the tank lid back on and make sure the flush rod doesn't strike the lid when you press the lever. If it does, bend it down slightly and readjust the chain.
Replace the flapper

Change the flapper

Unsnap the old flapper and take it with you to the store to find an exact replacement. In addition to the closest replacement, pick up a "universal" type.If you've completed the first three steps and your toilet keeps running, chances are you have a worn-out flapper. Turn off the water, remove the old flapper and take it to the store to find an exact replacement. (Hardware stores often carry a wide variety.) Most flappers snap over ears on the overflow tube. Others have a ring that slips over the tube.
Now here's the catch. You may not find an exact match. The range of flapper styles has mushroomed over the last 15 years, and you may find 15 to 20 flapper options on the store shelf. Some packages include specific brand and model information (so note yours before you leave home). Others have a "universal" label. If you can't find an exact replacement, try the closest one and pick up a universal type as well. They're cheap, and the extra one just might save you a second trip to the store! (Avoid the "adjustable" types unless you're replacing an adjustable one.)
Install the new flapper and make sure it opens and closes freely. Then test it. If the toilet keeps running or runs intermittently, you're not getting a good seal. Try a different flapper if the toilet won't stop running.
If you just can't find a flapper that seals, consider replacing the entire overflow tube/flapper. On most toilets (two-piece), this means removing the tank. It's not difficult and you don't need special tools. It'll take you about an hour, and you'll avoid that expensive plumber service call.
if you go to this link it will show you step by step on how to fix it. How to Stop Running Toilet Family Handyman

you adjust it by bendng the small tab on the float that presses on the end of the float needle,to check it is right find a length of clear tubing and put it on the small pipe bit that is on the bottom of the float bowl ,then bend it around the carb and point it upward s,then undo the drain screw on the float bowl and the fuel will come up the pipe and when it stops that is the same level as the fuel in the float bowl.its usually about 2/3 of the way up the float bowl.to low and it can starve it of fuel and too high it will flood and leak out.

Its probably the crankcase vent. The carbs have more than likely been pouring gas inside the motor,to the point of overfilling the crankcase oil with gasoline. Drain the oil and change the filter. And while youre draing it,..look inside the carb bodies,and see if gas is still running into the cylinders.If it is,then your float height is not set correctly..(too high)...or the needle valves need to be replaced. (valve that hooks onto the floats).

My first guess would be the float bowl for the carburetor. The fuel level needs to be maintained at a specific height in the bowl. There's a float inside that activates a valve which allows fuel to fill the bowl - once the correct level is reached, the valve closes. On my old Virago there were simply two tangs inside as I recall that needed to be bent manually to make the adjustment. To check the level you would attach a piece of clear tubing to the drain port on the bottom of the bowl.....when the drain was opened the fuel would fill the tube to the same level as is in the bowl. You would need to find the correct spec for that level and adjust if necessary.

Sticking floats or worn float valve needles or incorrect float height, tap float bowls to see it overflow stops (sticky float), remove and clean float bowls and fuel inlet passage with carb cleaner and compressed air, check float valve for wear to the rubber tip. Reset float height by slightly bending the metal tab on the float to adjust the closing height of the valve measure from the carb bowl mating surface to the top of the float when fitted then re adjust 1mm at a time higher untill fuel doesnt over flow.

check your flapper valve. Is it seating corretcly? Check the lenght of the flapper chain is it too long? Make sure the handle is tight so adjustment is correct. Check float to see where water level is. Is it above drain tube? If so move float down to decrease water height.

Is the drip comming from the small fill tube going into the overflow? If so you may need to raise it a little. The nost common leak is from the flapper or seal. On rare occasioms the flush valve itself has a defect that will cause it to leak. Take a close look at the problem and Im sure you will find it. I hope this helps.

YOU CAN ADJUST FLOATS WITHOUT SPECIAL TOOLS. ALL YOU NEED IS A FOOT LONG PIECE OF CLEAR TUBING, SIZED TO FIT THE BOWL DRAIN. SET FLOATS AS CLOSE TO WHAT THEY WERE WHEN YOU REPLACED IT. INSTALL THE BOWL AND PUT THE TUBE ON THE DRAIN. OPEN THE BOWL DRAIN SCREW WHILE HOLDING THE TUBE UP BESIDE THE CARB. WHEN YOU GET THE TUBE BESIDE THE CARB ASSY., THE GAS IN THE TUBE SHOWS YOU THE EXACT LEVEL OF FUEL IN THE BOWL. FROM THIS YOU CAN MAKE ANY ADJUSTMENTS NECESSARY FOR CORRECT LEVEL. THE LEVEL SHOULD BE RIGHT BELOW THE PLANE WHERE THE BOWL MEETS THE CARB BASE.