351 Driving Me a Little Nuts
 

Not as interesting as other threads but here it goes...
I have a '87 F250 which came with a carb. Over the years the pollution stuff has been disconnected as well as parts have died. I had the original carb rebuilt a few years back but it always ran rich. A month ago I finally bit the bullit and had a Holley 600 installed. The shop I took it too regularly works on carb equipped vehichles. They installed the Holley and it runs much better. The throttle return spring is a bit heavy but I will change that.

Now for the advice... It is a bit of a struggle to get started. It sits for a week or more at a time and I pump it twice to activate the choke and to give it a squirt of gas. I may have to repeat this a few times bu eventually it runs at fast idle to war up. When I put it into gear it dies and I try again and eventually, though a little quicker, it runs. After about fifteen to twenty minutes of driving al is well. The shop removed the EGR when they installed the carb.

Any ideas/solutions? Thanks in advance!

Re: 351 Driving Me a Little Nuts
 

I have a 1981 351m in my F250 and it runs a lot rougher than my 1955 crown victoria - which boggles my mind since it has an added advantage of almost 30 years of technology advances. I'm still learning my F250, but assuming its the same design does your vacuum motor in the air cleaner snorkel work? that draws in air warmed by the exhaust manifold until the engine warms up, after which cold outside air is funneled in. Mine runs, but isnt happy until warmed up. also, from what i've read, the PCV system should still be present and not messed with. And vacuum leaks are always a possibility.

Re: 351 Driving Me a Little Nuts
 

Something easy to start with...
Have you checked to see if the new carb is running lean or rich? A quick test is the color of the soot deposits just inside the end of the tailpipe, and confirmed by the color of the sparkplugs.
The choke may be set a bit too lean, possibly the main jets also?

Re: 351 Driving Me a Little Nuts
 

Could you elaborate on what the colors are/mean?

Re: 351 Driving Me a Little Nuts
 

In general, black is too rich and white is too lean.
A light brown or tan is about right.
Here's a link with images and descriptions....
https://speedmaster79.com/support/ho...r-spark-plugs-

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Re: 351 Driving Me a Little Nuts
 

It does have the PCV still hooked up. As far as the colour of the exhaust I will check that. I know it's a lot whiter than before as it used to look like an old steam engine going up a steep grade! So when I did look at the exhaust I was pleasantly surprised it was a lot whiter so maybe it's too white?

Thanks for the tip. I'll see what I can do or maybe take it back to the shop. It does idle a bit high once it has warmed up and it do s have a RV cam.

Re: 351 Driving Me a Little Nuts
 

Is the choke heated electrically or by a tube going to the exhaust manifold? If it's electric, is the power wire connected to the stator terminal on the alternator or just a hot wire from the ignition switch? If it's powered from the ignition switch, the choke starts heating (and opening) as soon as the key is turned on. This is wrong. It needs to connected to the 'STA' (stator) terminal on the alternator which has no voltage until the alternator is charging so the choke does not open too soon.
Also make sure the choke is closing completely when the engine is cold. It may be set too loose. Align the choke cap with the center notch to start with. If the carb has an external pull-off, it may be pulling the choke too far open when the engine first starts.

Re: 351 Driving Me a Little Nuts
 

This is a 351W/5.8L carbed engine, the factory carb a H4180 and it was replaced by a HOLLEY 4160?

How did they defeat the EGR (specialty spacer-different intake)?

Can you provide a photo of the install?

BTW- 40 Deluxe's description is right-on if it is a choke setting problem.

Re: 351 Driving Me a Little Nuts
 

It sounds like you don,t have any carb heat . i could be wrong , but as I remember ford used a snorkel from the exhaust manofold to the carb via the air filter housing and this was thermostatically controlled. When that air door didn't work correctly you would have cold engine drivability problems . As far as the cold start check the choke setting if it looks good make sure the carb is not leaking [look in the carb and make sure it has 4 or 5 good shots of fuel ]

Re: 351 Driving Me a Little Nuts
 

I'll be getting back to this nearer the weekend. Thanks for all the replies so far! Stayed tuned...

Re: 351 Driving Me a Little Nuts
 

You are not wrong but that design was mainly used to supply heated air to an emissions carb which was calibrated very lean so as not to over choke (emmissions). By his going to an aftermarket HOLLEY, it should be rich enough to stand on it's own. It is most likely either the choke setting and/or fuel evaporation (defeated EVAP System).

Re: 351 Driving Me a Little Nuts
 

I poked around over the weekend at my engine. I'm thinking it's the choke so I'm going back to the shop and let them sort it out. I'll keep you all posted.

Re: 351 Driving Me a Little Nuts
 

Just a little thing that it wouldn't hurt to double check... (photo)

Re: 351 Driving Me a Little Nuts
 

Thanks for that tip. I haven't opened it up but the shop said it will have to be next week. Maybe I'll review the set up procedure for chokes as I haven't done on in years and have a go.

Re: 351 Driving Me a Little Nuts
 

Did they change the manifold or did the Holley bolt up to the existing manifold? An increase in rpm is an indicator of a possible vacuum leak as a general rule especially if it started out normal and then increased in rpm over time. A lean condition may be another possibility due to some fuel passage partial blockage somewhere internally.

Re: 351 Driving Me a Little Nuts
 

Did the shop give you the instruction sheet for the carburetor? Choke setting and electric power hookup will be in there.

Re: 351 Driving Me a Little Nuts
 

I got the instruction sheet when I bought the carb. I believe that the Holley needs a constant 12v supply but I'm not sure. Got really busy around here lately.

Re: 351 Driving Me a Little Nuts
 

Correct. But the problem(s) you have seem to point to either choke setting(s) and/or fuel percolation.

Once properly adjusted (and before ethanol gasoline), one should be able to depress the fuel pedal fully and release and the car should start and run on it's own.

Can you tell me the HOLLEY MODEL NO.?

Re: 351 Driving Me a Little Nuts
 

How old is the fuel pump and is for a carbureted engine? There may be a difference, plus if the pump is old it may allow gas to drain back into the line and tank.

Re: 351 Driving Me a Little Nuts
 

Fortunateson,


I have an NOS Holley for an '86 Ford truck 351W. Part number E6HE-9510-AC. Holley number LIST 50305-2. Carb has always been in a heated house since new. Appears as new. If it comes to that point, just letting you know I have one (actually two).


Sal