New Carb, not starting
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New Carb, not starting
Hello,
On my 1981 F100 Custom with 4.9L 6-Cylinder, I have replaced the fuel pump, and the carburetor. The choke door closes as it should, and if I open the door and pump the accelerator, I see fuel spray. However, I have a lot of trouble getting it to start (usually requiring starter fluid or pouring small amounts of fuel in the carb).
Once it starts, it runs really well. Nice and smooth, aside from some dieseling after driving for a bit.
Any ideas? I really need to get this going so I can get supplies for our daughter's nursery before she comes in November.
On my 1981 F100 Custom with 4.9L 6-Cylinder, I have replaced the fuel pump, and the carburetor. The choke door closes as it should, and if I open the door and pump the accelerator, I see fuel spray. However, I have a lot of trouble getting it to start (usually requiring starter fluid or pouring small amounts of fuel in the carb).
Once it starts, it runs really well. Nice and smooth, aside from some dieseling after driving for a bit.
Any ideas? I really need to get this going so I can get supplies for our daughter's nursery before she comes in November.
Posting Guru
Joined: Apr 2011
Posts: 1,636
Likes: 5
From: Orlando area
Have you checked the ignition timing?
Are the plugs clean and not fouled? If you give the gas pedal 4 or 5 pumps, then crank, will it start easily then?
Usually dieseling occurs if the throttle blade is open too far (idle screw run in too far and idle speed too high). If the ignition timing is wrong you may be compensating by screwing the idle screw in further. Also if your carb has "idle mixture screws" be sure they are adjusted correctly or you may have the idle speed screw turned in to far to compensate.
Are the plugs clean and not fouled? If you give the gas pedal 4 or 5 pumps, then crank, will it start easily then?
Usually dieseling occurs if the throttle blade is open too far (idle screw run in too far and idle speed too high). If the ignition timing is wrong you may be compensating by screwing the idle screw in further. Also if your carb has "idle mixture screws" be sure they are adjusted correctly or you may have the idle speed screw turned in to far to compensate.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
A new or rebuilt carb is going to need some adjustment on the engine. Check fuel height in the bowl and adjust float height as required. This is an important adjustment because it affects everything. Then continue on with idle mixture and idle adjustment.
Most carburetors have some method of adjustment of the accelerator pump shot. Make sure it's set for the seasonal temperatures.
Most carburetors have some method of adjustment of the accelerator pump shot. Make sure it's set for the seasonal temperatures.
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
If you are pouring fuel into the carb to get it to start, just pump the gas pedal 2 or 3+ times, that should do the same thing. You pouring it in or using the carb to squirt it in, no difference. Pumping the gas pedal at least once is normal for a carbed vehicle. Some have "personalites" and may require several pumps before starting.
Hard starting "personalites" can be caused by low battery voltage, worn sparkplugs, and numerous other things. But as long as you get a routine down to get it going, that should get you through till you have time to figure it out.
Hard starting "personalites" can be caused by low battery voltage, worn sparkplugs, and numerous other things. But as long as you get a routine down to get it going, that should get you through till you have time to figure it out.
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