Hey all, looking for some advice. Proud papa of a new to me 66 F100. 352 motor with a 2100 2bbl. Relative newbie to engine tuning so don't want to jack something up without some input first. Choke is set ok, full choke closes just fine, opens same. I have just cleaned it out, cleaned it up and seem to be ok there. New gaskets of course. Where I run into my problem is once I go to no choke and hit the accelerator to rev the motor there is an instant loss of power like it is going to die and then it recovers and revs up. Front mix screws are both at like 1 5/8's turn. Wondering if i need to open up a little more if I am not getting enough fuel. Idle seems ok, no stutters or anything and overall it seems relatively smooth (for a truck that has been unloved for a while). Appreciate any input. Thanks!
Forgive the ignorant response, but if I am getting fuel into the carb, that should indicate the pump is ok (at least functional), correct?
The carb had 3 holes for the accelerator pump. Set it so it has the longest stroke.the third hole , at the pivot end of the accelerator pump arm. Check vacuum advance, and advance the timing 6 degrees.did you put the accelerator pump check valve (ball) in?
Take off the air cleaner and look in the carburetor, operate the foot feed with your hand the carb accelerator pump nozzles should squirt a steady stream into each venturi. If they don’t you need to change it and blow the holes. PS: how did your wife feel after giving birth to a truck?
Don't confuse "accelerator pump" with "Fuel pump". The accelerator pump is a part of the carb that covers the momentary loss of fuel flow when you begin to open the throttle. It's what makes the fuel squirt down the carb when you come off idle. SPark
Brilliant, thanks! Homework for tonight. And she felt better after she delivered. Should have seen her when she was carrying.....
Sorry I dropped the ball on your question but had some work to finish. Anyways the others have explained the accelerator pump function quite well and should help you to know what to look for.
Accelerator is definitely putting in fuel when it should, not sure if it is enough tho. Need to take the plate off that mounts on top of the output (into the venturis) to see more clearly. I have seen some pics online where it looks like people run without that plate. Is that a standard mod on that carb?
"Plate"??! We may need a picture. FYI.......(common mistake).... the two screw you were refering to that are screwed in about 1 & 5/8 turn.......those adjust the AIR... not the fuel. The jets (inside the carb) control the amount of fuel going in. Common mistake. Take those screws OUT. Squirt some carb cleaner/Brakleen/ether into each of the holes. Put the screws back in and gently run them in all the way. NOW...back them out about 2 &1/2 turns each. Hopefully it will crank right up. Screw one side in gently until the engine starts to stumble. Then screw it out until it starts to stumble. go half way in between! Do each side. Adjust the initial timing (with vacuum advance plugged) to about 12-14* and see if this helps. If not....increase the timing another couple degrees. See if there is an improvement. LET US KNOW how it turns out.(when you post the pics!) 6sally6
Some carbs had what Ford called a air distribution plate some didn't You should see fuel shooting past the plate.
Sunbeam hit the nail on the head. I didn't know official name (and didn't think to look at rebuild schematics). Air Distribution plate. I'm going to keep working on cleaning it up and go from there. Hope to have an update in a cpl days. Sent from my LM-V405 using The H.A.M.B. mobile app
Got the diverter plate off. Confirmed fuel is being injected a ok. Gonna have to hold off a bit tho for more tuning as I am tossing in a new radiator first as the old apparently was filled with some sort of mung. Sooooo, slight delay but I suppose I should be responsible and make sure little things like coolant stay in the system. Sent from my LM-V405 using The H.A.M.B. mobile app
New radiator in. Vac advance still in good shape and holding pressure. Now that rad is on, gonna start with the mix screws and idle screw. More to come Sent from my LM-V405 using The H.A.M.B. mobile app
Gee, thanks for that. BTW, I just magically tested vacuum accurately without a vacuum gauge.....oh wait.....Sorry I was giving those who provided some input without the snarky response an update. My build, my thread. If you can't respond without being condescending then move along. Sent from my LM-V405 using The H.A.M.B. mobile app
2100 is an excellent design. The period docs and manuals are available for viewing and download in .PDF if you dig around the 'net. There aren't a whole lot many adjustments to be made, but every one is very important. If you want to get them setup well you'll have to study the docs. A lot of information gets told and retold over the years and gets mangled in the translation. Study the primary source do***ents, and learn what's really supposed to happen, and how it really works. The accelerator pump rod and overtravel lever has several adjustment holes depending on the specific application, and climatic variation (temperature). The topmost hole on the overtravel lever is for wintertime use, temps below 40° F. The 2nd from the top is for temps between 40° and 80°. Make sure it's set correctly for the season. It makes a big difference.
Thanks! I was glad when I saw this was a 2100. Have a hard copy of the parts diagram and have been studying. Next going after the manual for more insight. Betwixt that, here and the Tube, my curve is accelerating considerably. Previous to this my work was centralized on an early 70's Impala (20 years ago now) so I am really just picking this back up. Sent from my LM-V405 using The H.A.M.B. mobile app
Just baseline everything to spec, as listed in the shop manual. If something won't adjust or respond correctly, find out why. The thing about carburetors is if one adjustment is made incorrectly or some component is whacked, the tendency is to try and compensate for that by screwing something else up. The vacuum gauge advice is a good one, if there are vacuum leaks, or the ignition timing is incorrect, the manifold vacuum will be too low to atomize the fuel well. Idle, and just off idle really is where a lot of driving is done. The idle circuit uses engine vacuum to meter the fuel. A healthy stock engine should pull a steady 19" to 21" at sea level, if it won't find out why, because you'll pull your hair out trying to get it running right. One thing about the 2100 series is that with many years of long use the throttle rod starts to wallow out the holes in the carb body oversize, introducing an air leak. Check for excessive side play or slop. The fix is drilling them out and installing bronze bushings.
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