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Weber 40DCOE - Does it need a check valve in the fuel supply line?

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DanLewis

DanLewis

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I've noticed that if I pull the starter immediately after turning on the ignition, it takes several tries to get the engine running. However, if I turn on the ignition (and thus the electric fuel pump) and then wait about 10 seconds before pulling on the starter, the engine starts right up and runs fine. That makes me think that it needs time for the fuel pump to fill the fuel bowl in the carb - i.e., that the fuel bowl somehow drains or evaporates overnight. I haven't found any leaks, so I'm wondering if somehow when the engine is turned off, the fuel is being drained backwards out of the carb and down the fuel line towards the tank?

Has anyone else ever noticed this with a Weber sidedraft carb? (Mine's a 40DCOE.) Would putting a check valve in the fuel line just before the carb solve it, or is this due to fuel evaporation from the bowl?

Dan
 
No idea, I don't want mine to start right away anyway. This is a good thing, go with the flow and build up oil pressure before it lights off. :wink:
 
kellysguy said:
No idea, I don't want mine to start right away anyway. This is a good thing, go with the flow and build up oil pressure before it lights off. :wink:
Click to expand...

Thanks for the suggestion, but it seems to me that as far as building up oil pressure first, it really doesn't matter whether the initial turning over is due to the starter or to combustion. Right?

Dan
 
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Mine did the same thing, especially if the car sat for a week or more. I'd let it prime for about 7-8 seconds, then it would fire right up.
 
DanLewis said:
Thanks for the suggestion, but does it seems to me that as far as building up oil pressure first, it really doesn't matter whether the initial turning over is due to the starter or to combustion. Right?

Dan
Click to expand...

I'll let you answer that: Which do you think applies more pressure and force, 200#s of compression or an air/fuel explosion?

The idea of pressure "lubrication" is not only to lube but provide a film for the bearings to "water ski" across. I'd much prefer my bearings under full possible lubrication before maximum low speed load is applied.
 
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