Ford 4000 Carb and timing problem

[FordPig]

I just brought home a 1963 Ford 4000 and I'm having a few problems with it.

It fired up instantly without the choke, even cold. But whenever there's a load on it you can hear it pinging. It will also diesel about 75% of the time when shut off. The idle on it is about 900 RPM. When increasing the throttle from idle it will die unless it is done VERY gently.

I did a little bit of tweaking on it, the manual calls for 4 degrees BTDC. It does not have a vacuum advance, so nothing to unplug when I'm timing it. I played with the timing and was able to get it to smoothly rev up without killing it, but the timing ended up at around 30 degrees BTDC!!

I set it back down to around 5 degrees, and started tweaking the carb. Based on a few things I read from here. I have the idle speed down to around 450 now, and it will start reliably. I still have that massive dead spot when I try and throttle up from idle though. Timing light shows it at 20 BTDC when running at 2000RPM, so it is advancing. I believe the manual calls for 25 degrees though?

The carburetor has 3 adjustments that I can see. An idle speed screw on the throttle, a screw on top of the carb at the front, and a big T handle screw at the bottom just in front of the drain on the bowl.

As I understand it the small screw on top is the idle air screw, and the big T handle screw on bottom is the load/power screw?

I'm going by this thread here: http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ford&th=21690

Am I understanding it right and the big screw referred to is the big T handle on the bottom of the bowl?

How should I go about tuning this?

 

[Will Gumbert]

Sounds like you may have several problems which
can be hard to sort out. The pinging under load
can be caused by timing too far advanced and/or
other things like the engine running too hot or
too lean. Based on your post, sounds like the
mechanical advance is working about right if you
set the timing around 4 deg at idle of 450rpm.
Advance starts at around 500 rpm and at about 1200
you should be at roughly 13 deg. Did you first
check your point gap at .025"?
For the carb, you should likely have a MS TSX 813
and the idle adjust needle is the air-adjusting
type so turning it IN (CW) is richer. The larger
adjustment on the bottom of the fuel bowl is the
power adjusting needle and if uncertain where it's
set, might be a good idea to turn it all the way
IN (CW) and then OUT about one turn as a starting
point. Don't forget to loosen the packing nut
before adjusting. To really adjust it correctly
you have to have the engine under load while
adjusting which is not easy to set up.
These are simple carburetors but rely on small
orfices being clean to give proper calibration.
Another common problem is worn throttle shaft
bushings allowing air in and throwing off the
calibration. This is usually compensated for by
adjusting it richer but correct fix is new
bushings. You can check this by spraying some
Gumout at the shaft while engine is idling and see
if it causes stumbling. If you are so inclined, it
might be good to take the carb off, tear it down
and clean and check everything including float
level and needle and seat. Be sure to change the
gasket under the main nozzle. (get rebuild kit
first). Will

 

[FordPig]

Thanks for the information and all the good advice. I didn't think to check the point gap either. I'm glad you mentioned it being .025, I probably would have assumed it was .015 like my old 8N.

 

[souNdguy]

sounds like a zenith carb...

 

[FordPig]

It may be, it doesn't have Marvel-Schebler cast into the side of the bowl. I haven't noticed a name anywhere on it.

 

[souNdguy]

they look 100% different anyway.. tyhe MS and clones of MS all lookt he same-ish.. the zenith are a whole different breed.

 

[FordPig]

Edit ---- somehow posted in the wrong thread.

 

[FordPig]

Alright I'm at a loss here. No idea how to proceed.

Yesterday I sprayed carb cleaner all around the carb when idling. Not a stumble or any change whatsoever.

Last night I shut it off, it was running and idling fine, it just wouldn't rev up without killing it unless I did it very slowly. This morning it wouldn't start at all.

I checked the points, set them at .025

Swapped the plugs out for new Autolite 437s.

I checked that the distributor wasn't in on the wrong timing gear tooth. The #1 piston at the top of it's stroke shows 0 on the flywheel, and the rotor is pointing at the number 1 wire on the distributor cap. Everything is good there. I'm getting good strong spark at the plugs. I also double checked that the firing order is correct.

The ONLY way I can get it to start right now is to advance the timing until it's past the 30 degree BTDC mark. probably in the neighborhood of 40 degrees. I can turn it down to 25 after it's running, but then I can't start it again.

It also will NOT start unless I have the throttle all the way closed. It will not start with any choke. It has to be started at a dead idle or not at all. I pulled the air filter loose in case it had a blockage and was already "choked" through the air filter. No change.

I have the carb adjustments set at 1 turn (a turn being a full revolution of the screw) out from seated.

I just pulled the carb apart, it looks like a fresh rebuild inside, blew everything out, checked the float level and put it back together. it's at least not dying on me at idle anymore, but it has to idle at 700 to 800 RPMs, and the advance still has to be about 25 to 30 degrees for it to start. It still is unable to be throttled up without dying unless it's very very slowly.

I also triple checked the fuel supply to the carburetor. all the lines are clear, everything is flowing properly with a good strong flow from the tank to the sediment bowl.

Does anyone have any ideas what else I could try?

---- Edited for current problems

 

[andreiwright]

It sounds like you need an alignment, first thing you need to get is a shop manual. I think an I&T FO-20 manual should be sufficient. It's brief and to the point. They will have photos illustrating the timing marks aligned. You got to act very quickly.

 

[Will Gumbert]

Sorry, I did not see your last post for a long
time. If you see this, might be a good idea to
start a new thread.
Sounds like you checked the spark and timing
thoroughly so indications are still a fuel/carb
issue or possibly even a cam timing problem. Can
you run a compression check on all 4 cylinders?
For the carb, it still could be a blocked passage
causing it to run too lean while on the idle
circuit, but usually applying the choke helps with
that, but not in your case. Might be nice to know
if it is a Marvel Schebler carb. If so it will be
stamped on the thin edge of the mounting flange.
There are experts here that probably could help, a
new subject thread will get some attention. -Will