[Bulldog 61]

My son has issues with his Coily, cranks over for maybe 2-3 minutes before it will start. He only has the issue if its been sitting for 3 or 4 days and once it fires up it runs great. It appears as if the fuel is draining back to the tank but I would have thought there would be enough for it to start at least initially left in the carbie.

Any advice is appreciated, stock G13ba with stock carb.

cheers

[alien]

Smell the exhaust on first startup to see if it smells rich (eliminate flooding from the equation)

I assume you've tried pumping the accelerator while starting?

[fordem]

First time I've ever heard of fuel draining back to the tank with a carburetor - once it's in the float bowl, there's no way to get it back to the tank. I'd be checking to see how it gets out of the float bowl - a loose plug perhaps (assuming it's an Aisin where you have to remove a brass plug to get to the main jets.

[Bulldog 61]

alien wrote:

Smell the exhaust on first startup to see if it smells rich (eliminate flooding from the equation)

I assume you've tried pumping the accelerator while starting?

yeah makes no difference, I did try dumping a bit of fuel down the carb once and it fired straight up but only ran for about 5-10 secs

[Bulldog 61]

fordem wrote:

First time I've ever heard of fuel draining back to the tank with a carburetor - once it's in the float bowl, there's no way to get it back to the tank. I'd be checking to see how it gets out of the float bowl - a loose plug perhaps (assuming it's an Aisin where you have to remove a brass plug to get to the main jets.

I might try to find another good carb and try it

[bumstein]

Same thing happens on two of the sierras I've had.. Fuel can't leak out the float chamber easily.. I always put it down to the fuel pump perhaps being a bit old. One way valve allowing fuel to settle in the line?

Even if there is fuel in the float chamber perhaps it needs a little positive pressure from the fuel pump to get it to jet properly?

Thinking out loud here.. No tangible evidence

I just put up with it, never tried to fix it. A spray of Start Ya Bastard works a treat..

[Reubs]

Replace the fuel pump. Stuff easy to fix and easy to diagnose. Pull the fuel line and see if it pumps when cranking.

[Bulldog 61]

Reubs wrote:

Replace the fuel pump. Stuff easy to fix and easy to diagnose. Pull the fuel line and see if it pumps when cranking.

yep new fuel pump and filter was the first thing I did, no change. pumps fuel after about 20 secs of cranking but even then after you connect the fuel line back up it still takes another 20 secs of cranking before it will fire....................so I guess its not that easy to diagnose ??

[cairns27]

Maybe a air leak between the tank and the pump


bye

[Reubs]

About 2 dozen manual pumps of the pumps lever should see fuel at the pump so something sounds wrong there.

[Bulldog 61]

So I finally got around to fitting an overhauled carb I had sitting around and the thing starts within 2-3 secs now. Havent stripped the original down yet but I'll be interested to see what I find

[bumstein]

Win!! Let us know how the old carb rebuild goes. I've pulled one apart myself, black art IMO, not sure I'd fully trust one that I've rebuilt myself.

[Bulldog 61]

Yeah Im keen to know what was/is causing the problem. Will be a while as Im away for work for nearly 4 weeks straight.

cheers