Weber Carb issue

[LaneRover]

I have the dual Weber carb on my 1965 Station wagon.

Once started it runs great, drives great . . . once it is started . . .

If it sits overnight it takes forever to start. It cranks and cranks and cranks eventually sputtering and spitting reluctantly before running.

If I pour some gas down the carb it starts right up. So obviously a fuel problem.

Any thoughts?

[Finbar]

I had the same issue with a Weber single carb. What is happening is that the gas in the fuel line drains back to the fuel pump. Others on this forum will know better than me whether this is indicative of a faulty mechanical fuel pump or something else. If anyone knows please speak up.

In any case, one solution, and the one I adopted, is outlined on this forum. Here is the link:

http://forums.roversnorth.com/showthread.php?15485-Motor-stalls-on-first-crank-then-runs-beautifully&highlight=facet

It basically involves placing an electric fuel pump after the mechanical one. I installed an AIRTEX E8016S, Electric Pump; Solenoid;12 volts; 2.5-4.5 PSI; 30 GHP; 5/16 hose. Stay away from Mr. Gasket pumps, they're terrible. I wired it back to a switch in the cabin that is only active when the key is turned half on. I turn the key to get charge, flip the switch and let the electric pump run for a few seconds and then turn the key the rest of the way. It starts on the first try every time. It was very easy to wire. One wire to the cabin and a ground to a good ground in the engine bay. I put an inline fuse in the line to the cabin and the source of my 12 VDC is only on when the key is half on (i.e. when the car is on). Once the car is started I let the pump run a couple more seconds and then I turn the electric pump off. I'm pretty sure that if my mechanical pump ever stopped working I could just switch on the electric one and leave it on to get me where I needed to go.

[80sailor]

I replaced my fuel pump.

Worked like a charm.

[LaneRover]

I am going to try it - to me it doesn't make sense because I hand prime and when I do I get gas coming out of the hose (if I take the clamp off and pull the hose to check). But maybe it is just weak and needs a little extra nudge.

Once its going it goes just fine.

[bugeye88]

Electric pump after the mechanical is a good solution. This has been gone over several times on this site. On/off switch under the dash also nice. This can be a back up for a failed mechanical pump when mounted after the mechanical pump with no risk of pumping gas to the crankcase. This set up works well with my Weber 34.

Cheers
Rob
Bugeye88

[TedW]

The Carter 4070 electric pump has worked great with my 34. Remove the mechanical pump and don't look back, in my view. Carter also offers a power solenoid that works off of oil pressure: the solenoid needs to sense a bit of oil pressure before sending power to the pump. Conversely, it will shut the pump off when oil pressure goes away, preventing the pump from spewing gas after an accident.

[LaneRover]

Carter also offers a power solenoid that works off of oil pressure: the solenoid needs to sense a bit of oil pressure before sending power to the pump. Conversely, it will shut the pump off when oil pressure goes away, preventing the pump from spewing gas after an accident.

Interesting!

[TedW]

Interesting!

And I recall it set me back about $17.00.

[LaneRover]

And I recall it set me back about $17.00.

Highway robbery! Luckily I don't go on the highway much . . .:cool:

[LaneRover]

Well I wish that worked . . . Got a pump temporarily wired it in and plumbed it right between the mechanical fuel pump and the carb. Let it pump fuel and then tried to start - got a big fat nothing, exactly the same as the mechanical pump. It definitely was pumping because I used it to pump a bit of extra gas into the carb throat and it started right up.

I am pretty convinced it is the accelerator pump . . . any other thoughts?

[bugeye88]

LR,
Well if the electric pump is pumping well into a container then its not just the mechanical pump. Next guess would be crud in the carb. Webers are extremely sensitive to crud blocking the many and various jets in various models of Webers. Look at the jets in the carb and place a in-line filter after the electric pump.

Rob
Bugeye88

[Contractor]

Well I wish that worked . . . Got a pump temporarily wired it in and plumbed it right between the mechanical fuel pump and the carb. Let it pump fuel and then tried to start - got a big fat nothing, exactly the same as the mechanical pump. It definitely was pumping because I used it to pump a bit of extra gas into the carb throat and it started right up.

I am pretty convinced it is the accelerator pump . . . any other thoughts?


I am no expert, but I fail to see the connection between a hard start and the accelerator pump?

Maybe someone else will chime in.

[SafeAirOne]

I am no expert, but I fail to see the connection between a hard start and the accelerator pump?

My money would be elsewhere too, since the function of the accelerator pump is to inject extra fuel into the throat of the carb to keep the engine alive and revving up until thee vacuum can catch up and draw fuel in the normal way during strong acceleration events.

[LaneRover]

Whether or not it is THE issue it does have issues . . .
10399
maybe I am thinking about it wrong but if it's the job of the accelerator pump to squirt fuel down the throat of the carb and the truck starts well after pouring some fuel down the carb then I see a connection. Thank you for all the help - I hope I won't need more for this issue after I try this fix!

[yorker]

maybe I am thinking about it wrong but if it's the job of the accelerator pump to squirt fuel down the throat of the carb and the truck starts well after pouring some fuel down the carb then I see a connection. Thank you for all the help

most kind of work that way so it should help. See :
http://42fordgpw.com/pdfs/solex.pdf

Different carbs but it describes and contrasts how they work for starting.

[LaneRover]

most kind of work that way so it should help. See :
http://42fordgpw.com/pdfs/solex.pdf

Different carbs but it describes and contrasts how they work for starting.

That actually helped (I think). I was able to do a bit of fiddling and it looks like the choke isn't closing completely either, and I saw gas down in the base of the intake manifold so I know that some gas is starting to get through. I ran out of time last night so I let you know more once the fiddling is done.

[LaneRover]

OK, so after replacing the accelerator pump (which was needed) and correctly reconnecting the choke so that it will close completely the Rover starts A LOT better. I think it was a bit of both but neither one or the other alone. The article Yorker wrote helped me understand a bit more about carbs and realize the choke was part of the problem.

Thanks everyone for your help!