The Ford Barn

Minn-Tex Lee · 09-15-2015, 01:06 PM

I have a miss or rough running engine when cold. This just showed up. I have 1200 miles on the rebuilt engine. The GAV is at 1/4 ccw. Changing it makes no difference. I changed the plugs. No difference. I start full retard and run 3/4 advance.
The problem seems to go away after 4 miles.
Could it be a stuck intake valve? How much trouble is that to fix?
Any thoughts on this would be appreciated.
Lee

Brentwood Bob · 09-15-2015, 02:43 PM

tillotson, or zenith carb.?

Gabalus · 09-15-2015, 02:48 PM

Condenser ?

Minn-Tex Lee · 09-15-2015, 02:48 PM

Tillotson

Minn-Tex Lee · 09-15-2015, 02:50 PM

I thought a condensor problem would show up as a problem when hot. I could be wrong tho.
Lee

Jim/GA · 09-15-2015, 05:13 PM

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What you describe is actually pretty normal for a cold engine, until it warms up, but it usually clears up by opening the GAV a bit when cold.

1. Make sure turning the GAV knob is really turning the GAV on the carb. Repro choke rods have the knob screwed on and it is possible to turn the knob without actually turning the GAV.

2. It could be a blocked passage. Take the carb off and apart, open the GAV a lot, spray through each jet backwards with spray carb cleaner, follow that with compressed air. Then put it all back together and test.

09-15-2015, 01:06 PM	#1
Minn-Tex Lee Senior Member Join Date: May 2010 Location: Stewrtvl MN-Fredbrg TX Posts: 192	Miss or rough running when cold I have a miss or rough running engine when cold. This just showed up. I have 1200 miles on the rebuilt engine. The GAV is at 1/4 ccw. Changing it makes no difference. I changed the plugs. No difference. I start full retard and run 3/4 advance. The problem seems to go away after 4 miles. Could it be a stuck intake valve? How much trouble is that to fix? Any thoughts on this would be appreciated. Lee

09-15-2015, 02:43 PM	#2
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,420	Re: Miss or rough running when cold tillotson, or zenith carb.?

09-15-2015, 02:48 PM	#3
Gabalus Senior Member Join Date: Jul 2012 Location: France Posts: 113	Re: Miss or rough running when cold Condenser ?

09-15-2015, 02:48 PM	#4
Minn-Tex Lee Senior Member Join Date: May 2010 Location: Stewrtvl MN-Fredbrg TX Posts: 192	Re: Miss or rough running when cold Tillotson

09-15-2015, 02:50 PM	#5
Minn-Tex Lee Senior Member Join Date: May 2010 Location: Stewrtvl MN-Fredbrg TX Posts: 192	Re: Miss or rough running when cold I thought a condensor problem would show up as a problem when hot. I could be wrong tho. Lee

09-15-2015, 05:13 PM	#6
Jim/GA Senior Member Join Date: May 2010 Location: Young Harris, GA Posts: 1,964	Re: Miss or rough running when cold Sponsored Links (Register now to hide all advertisements) What you describe is actually pretty normal for a cold engine, until it warms up, but it usually clears up by opening the GAV a bit when cold. 1. Make sure turning the GAV knob is really turning the GAV on the carb. Repro choke rods have the knob screwed on and it is possible to turn the knob without actually turning the GAV. 2. It could be a blocked passage. Take the carb off and apart, open the GAV a lot, spray through each jet backwards with spray carb cleaner, follow that with compressed air. Then put it all back together and test. __________________ Jim Cannon Former MAFCA Technical Director "Spread the Joy! Have a Model A day!"