[old fords]

I am asking this for a friend. he has a 78 F-100 4x4 with a 460. It has a 600 holley on it. It will stop running randomly and runs real rich. He said it will crank fine. I was wondering what could cause this. Thanks for ny help

[47 ford tudor]

hi have your friend to ck floats may be sinking or power valve

[T-bucket23]

You may also want to check for proper choke operation

Chet

[Irelands child]

My history with older Holley's and crappy running is that the power valve has gone to heaven, usually from a backfire while starting cold. Later Holley's have a check valve that will usually prevent these failures and there is a 'kit' that can be installed as well for less then $15 from Summit (their p/n Hly-125-500) plus a new 6.5 power valve.

Once that's fixed, then the choke usually needs some attention.

Another problem with Holleys - throttle shaft wear (Summit p/n HLY-20-48-1 for a 4160 is one of several repair kits)

Then - it might just need a major overhaul or just plain need to be trashed and a new one installed

[curtis73]

Our motorhome with a 460/holley was idling pig rich at about 400 rpms.

New power valve and a little tune up cured it.

[Jmark]

You may have two problems. In the '70's, the Ford ignition box gave everyone fits. If your friend still has the Ford electronic ignition, have him change the box. It's the silver rectangular box under the hood. It's about 5" square and has two wire harnesses coming out of it. The main symptom was the engine would just shut off for no reason, then usually fire back up again after coming to a stop and sitting for a few seconds or minutes.

you may also have a carb problem too. A blown power valve (very common) will really fatten up the mixture and cause smoking and horrible mileage.

Mark