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Fuel question for 521 with L20B engine


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Hello guys. My truck has been running nicely for a while now. But recently it doesn't want to start in the mornings. It seems that the fuel doesn't reach the carb when cold. If I add gas to the carb manually then it starts right away and will start and run fine for the rest of the day. I can see that the fuel filter is empty in the mornings and only after I prime the carb it fills up. So I'm guessing the fuel pump is working fine, but can't figure out why it does this. Any guesses?  Thank you all.

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Fill out you profile more. Put the year of your 521 in it. Some were manual choke some were electric. Saves asking.


Fuel flow through the filter is not needed for starting. There is more than enough gas stored in the float chamber to start the engine and drive a block or two. If hard to start try stepping on the gas 3-4 times first then try starting.


If this gets a reaction but still not enough to start then the choke is probably not right. When the engine is cold in the morning take the top of the air filter off and take a look. The choke flap will be open or partly open. Have someone step on the gas pedal. What you should see is the choke flap snap closed suddenly. Does it?

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Thank you guys. So I took it to a friend and you were right Mike. The float chamber is filthy and the float gets sticky hence no gas to the carb when cold. I ordered the kit and I'm going to rebuild it. Thanks again. 

As for my truck, it's a 1970 with manual choke, but the previous owner replaced the engine with a L20B.

Thanks again guys!

I'm going to try to figure out how to post pics.


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