Silver Series 6.5hp Tecumseh runs for 5 seconds and quits. Any ideas?

[FuzzyDriver]

You could also use a piece of wire from a wire brush.

 

[Rivets]

I also use micro drills, but the largest I think I’ve ever used is a #76 which is about .018”. Bought a pin vise hand drill about 15 years ago for about $5.00.

 

[JohnFrancis]

Hello, and thank you in advance for any help you may have. I have a Silver Series Lawn Boy with a 6.5hp Tecumseh engine and electric start. There is no throttle control or choke. I runs for about 5 seconds when I spray it with starting fluid and then quits. This morning it did run for 5 seconds on it's own fuel, but then quit too. I took the carb apart and cleaned it carefully. It is now the cleanest carb on the planet. I put it all back together, and I get the same problem. The fuel tank is clean and fuel flows properly, and the gas is new premium. Oil level is full. So with my limited (carpenter by trade) knowledge, I'm stumped. Can anyone suggest anything to look into ? Thanks!

Pull the spark plug. If it’s dry, then it’s likely fuel starved. Either a clogged fuel cap vent or a misadjusted fuel float/needle valve. If it’s wet, then the fuel bowl is probably adjusted too low.
Beyond that, could be a bad coil or ground.

 

[Rick42wood]

Does this carb have a shut-off solenoid?

 

[QuantumLeap]

Cleaning out the jet could be helpful but most likely the bad gasoline that most likely sat in it has hardened the rubber components. It would be best to replace the needle and seat inside the carburetor and give it a good cleaning.

The engine is running on the fuel that you are forcing into it through the primer and then it can't meter its own afterwards so it dies.

The good news is you've tested the spark and compression so that leaves air and fuel. Unless the air filter is completely plugged has air. If cleaning the car up on its own doesn't work I would get a rebuild kit. It has the needle and sea as well as a bowl gasket and potentially mounting gaskets.

The floats on Tecumseh's are adjustable and they have service manuals showing what they should be adjusted at. If you're willing to take the car up on and off a few times you can probably find out where it should be on your own. I would leave the float adjustment where it is and do the needle and seat first and then adjust from there.

You can also Google the model numbers and get a knock-off card online for $20 or less. I've been surprised how many of these do work for how cheap they are and if you've never rebuilt a carb they're a pretty decent option.

 

[QuantumLeap]

Does this carb have a shut-off solenoid?

It should only have the bail bar you have to pull down when starting no other stop switches.

 

[QuantumLeap]

Pull the spark plug. If it’s dry, then it’s likely fuel starved. Either a clogged fuel cap vent or a misadjusted fuel float/needle valve. If it’s wet, then the fuel bowl is probably adjusted too low.
Beyond that, could be a bad coil or ground.

These coils ground through the mounting spots on the block so ground is a rare issue. Since it starts and dies I wouldn't think the coil is bad because it would need to run long enough to get hot. To test this you can let it run until it dies and then pull the spark plug off and test the spark immediately after.

 

[Earthquake Landscaping]

Basically, even if you've cleaned the carb spotless, unless you put it in an ultrasonic cleaner, it's not cleaned where it's plugged. If you can get your hands on a jewelry cleaner, it'll do the job just fine. Disassemble the carb and run the cleaner for 20 minutes. reassemble and try again. If you can't find an ultrasonic cleaner, then try this... That it'll run for a few seconds indicates there is some fuel flow through ( probably) restricted fuel passages. Dump about 1/4 can of Seafoam into the gas tank. Now drain gas at the fuel bowl until the gas with the Seafoam in it is entering the fuel bowl. Start the engine a few times, and then let the Seafoam sit and soak the interior passages of the carb. If there is at least some fuel flow through the passages, the Seafoam should start to dissolve them.
The use of Seafoam is a bit of a band aid approach to the problem in the carb, but it will work to a certain extent if it can flow into restricted passages.
IMHO, a plugged vent cap may cause issues, but it'd run longer than a couple of seconds. Way longer.

 

[Gord Baker]

I agree that it is still in the carb. I take a wire twist tie, burn off the plastic or paper on it, then use it to clean out all the tiny holes you can find.

Use a wire from the Wire Brush.

 

[Gord Baker]

Remove fuel tank cap and try to start it. If it starts and runs, the vent is clogged in the tank cap and you need to open it up. It the cap advice doesn't work, remove the fuel bowl nut and clear the fuel jet openings in the bowl nut with a small wire (.010-.012") diameter, like a twist tie wire. Good luck.

Remove, clean and gap or replace spark plugs.