I know this is a little non-mustang related but I know you guys have the knowledge and expertise to help me.

I'm trying to help my neighbor get his '78 F250 started. It's a 460ci engine with 4bbl motorcraft carburetor.

So far we've replaced the spark plugs and wires. Confirmed the firing order 1,5,4,2,6,3,7,8 And a rebuilt motorcraft carburetor.

When we try to start it, the engine just spits and spins. Also, a lot of fuel is splashing out of the carb and everything. He isn't even pressing the gas pedal while starting.

Is there anything you guys can think of that we could check?!?! The battery is now charging because it died while trying to start it.

If you have any questions, let me know.

Thanks in advance.

Erik

Also, check to see if the distributor rotor is turning and is correctly timed to rule out a blown timing chain.

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'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
MCA Member # 47773

I'm really still a novice at carburetors and this may sound a little newbyish but how would I check for a stuck float or leaking needle and seat assembly? The carb is new by the way.

I will check the distributor rotor tomorrow. To check that all I have to do is remove the cap and turn the ignition right?

I know I sound really novice, but i'm trying to learn as much as I can. I really appreciate the fast response and great HELP!!

Thanks in advance.

Erik

quote:

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Originally posted by rockafellz:
When we try to start it, the engine just spits and spins. Also, a lot of fuel is splashing out of the carb and everything. He isn't even pressing the gas pedal while starting.

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Is it backfiring? It sounds like the engine is out of 'time'... if in fact the carb is new, I wouldn't think it's got problems (or would hope not). If you've re-wired the distributor, have you checked the rotor rotation to your wiring sequence? It isn't hard to get mixed up sometimes...

Well, my Dad and my neighbor wired the plug wires counter clockwise 1,5,4,2,6,3,7,8. I myself, haven't actually seen the rotor turn counterclockwise though.

Can anyone confirm?

Erik

To check, you would need to remove the top cover of the carb and look at the needle&seat assembly and see if there is dirt or debris, or tears on the neoprene/viton tip. Sometimes people forgot to replace the O ring under the seat. You would then check the float for proper adjustment for both float height and float drop. Many people don't adjust the float drop which can cause a stuck float. Last, you check the float for scratches, which can cause the float to be 'waterlogged' {'fuellogged?'} and make the float worthless.

To check the rotor, take the cap off and watch the rotor and make sure it turns as the engine turns. Then verify the timing is right by taking off #1 spark plug and finding Top Dead Center, when the plug is due to fire, by sticking your finger over the spark plug hole. Compression will push your finger off the hole as the compression stroke starts. Then watch the timing mark on the balancer and when TDC lines up to the mark, check to see if the rotor is pointing to the distributor terminal for the #1 spark plug wire.

Actually, before you even check the rotor, verify that you have spark at the end of the spark plug wire. Pull the spark plug, put it back on the wire, lay it on the engine block and look for the spark as the engine turns over.

It's all a process of elimination.

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'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
MCA Member # 47773

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'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
MCA Member # 47773

-The rotor is spinning
-The plug wires are connected correctly

-They pulled the spark plugs and there were CLEAN. Not fouled, Not wet, No gas smell whatsoever. They're thinking that the fuel isn't getting down into the cylinders. I couldn't believe it since that carb is spitting gas like I take a leak.

-One correction from my first post, they actually returned the new carb and they've been working with the original carb all along. They also haven't had a chance to pull the carburetor yet.

Thanks for all the help.

Erik

p.s. Can you believe the OEM Motorcraft replacement carb costs $399.00 + $27.00 core? Seems a little insane to me