37 posts in this topic

 Okay-the jets from my original carb appear to be #40's. (Looks like "AOF"to me,but my eyes aren't as good as they used to be.) I think I've decoded the number to be "40F". Does that sound right? I got them out with a minimum of damage (for ME). (BTW-I understand the older Holley carbs,whatever "they" mean by older,used the same jets as the Motorcraft carbs,but Motorcraft carbs have always been the same.)I also snagged some pieces of the fast idle cam and adjuster,since I believe that's the linkage my other carb is missing.

   I also got the metering rods;it's the block between the bores,has a big screw with a little pushrod and a ball under it and another screw holding it in,right? (I assume there's a spring too,but I didn't find one when the other two parts hit the floor.)

As soon as I can withstand the cold long enough,(Still pampering the lungs from this cold;don't wanna let it turn into Pneumonia again,ya know.;)) I'll go pull the carb off the BroncWorth,swap the main jets and see what I can do with the linkage. I have a couple of new base gaskets that are fairly thick,so they should take care of any vacuum leaks.

Yeah,the 10si would be the cheap/easy cure,and that sounds good to me. A-I have to get this thing reliable before actual Winter hits,and B-I'm so tired of fighting all these little gremlins I could scream. The Toyota's gonna get 10si'ed too,when I change the engine. Its alternator still works fine,even oil saturated,but why risk a catastrophic failure I can't fix out in the middle of God's Country? At least I can carry some spare parts and replace a Voltage Regulator,brushes,or the diodes if I have to.

Speed

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Speed...You need a fighting chance...First off, I should have qualified that there are no metering rods like a Carter or Rochester carburetor (which dip into the metering jets).  I meant the booster venturi cluster assemblies with tubes that you describe.  This is a fuel metering means.  If the tube orifices are different between the 2.8L and 302 venturi boosters, begin with the 2.8L boosters and tubes.  Likewise, use the 2.8L main metering jets for starters.

Not sure whether the 302 and 2.8L 2100/2150 carburetors are similar model years and design.  There were feedback and non-feedback Motorcraft carburetors over the years and even in given model years.  Parts interchangeability is dictated accordingly.

Use a carburetor rebuilding kit's diagrams and set of instructions for a sensible build.  No need to create undo complication here!

Moses

Edited by Moses Ludel

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Got the jets and metering rods changed. I cleaned up the spacer and used new relatively thick gaskets,one below and one above the spacer,backed off on the fast idle screw about half a dozen turns,marked the timing marks enough to see and set the timing around 13 degrees. (Motor's manual says 12 degrees for a '76 Mustang,which is basically what this engine's set up like,now.) Runs a ton better,but still feels slightly off. Now it starts pretty easily,idles well,cold it needs only 10 seconds of choke before it'll run okay without choke. Mixed signals;acts like it's a little rich still,but under load acts lean to me.

Going over the Summit to Spring Creek last night it started doing a violent,driveline jolting misfire every time I got into the throttle under load. Giving it about 1/3 to 1/2 choke smoothed it out but it didn't wanna pull anymore. I might back the timing off 2 or 3 degrees and see if that makes it happy. (Also noticed my throttle cable has a stiff spot just off idle-push and nothing happens,it won't move,push a little harder and it jumps to WFO. Hard to drive with finesse  that way. Not an issue if I'm racing it.) Over all,seems to have a lot more power. Used 1/8 tank of gas to go approx. 30 miles since getting it running. I'm guessing it was running about 8 mpg when it was jetted wrong,and probably around 16 now.

   Question-What's a relatively cheap/easy way to add a couple of inches of lift to the B-II front suspension? Since I added overload shocks on the back,and I don't carry as much weight as I'd planned,I'm noticing it drives VERY twitchy on the highway. I've also noticed a little wear on the insides of the front tires.

   Speed

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Speed...Raising the front end of any Ford Twin-Traction Beam front end is neither cheap nor easy.  The entire front axle needs to drop down as an assembly, there are aftermarket kits for the Bronco II and Ranger pickups, kits relocate/drop the pivot points and provide longer springs and shocks.  Otherwise, simply lengthening the front springs will only push the ends of the axle halves downward from their current anchor pivot points and cause the front wheels to go positive camber.  You get the picture, much like jacking or lifting the vehicle up by the frame and watching the front wheels drop in a positive degree camber arc...

The wear pattern at the front tires is either toe-set error or negative camber.  Negative camber could be sagging springs in all likelihood.  Toe-set is easier to address.  As for the rear overloads, they're likely overloading the back axle and frame, pitching the weight forward.  This would impact handling with a "bouncy" rear axle and irregular weight distribution front to rear.

Moses

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Got the main jets and metering rods/tubes changed;the tubes were different so the original carb top wouldn't fit,so I used the one off the original carb. Problem with that is that the two screws at the end of the float bowl fit,but the next two holes in the lid go into the corners of the float bowl,and the last two holes that straddle the air cleaner stud tower,go into thin air. I figured,"No problem,I'll just screw the air cleaner stud in,run a nut and washer down on it and that'll hold that end of the carb top down. Close,but no cigar. Unlike the older carb body,the newer body isn't threaded for the air cleaner stud,the TOP is. So I had to drill that hole out in the carb top,find a bigger diameter stud to fit the threads in the old carb body,and find nuts and a washer that fit. Finally got it together,and it runs pretty good,except under load,like going up a hill,where it goes to crap. A riding buddy asked me if I checked the power valve,and I said,"It's a Motorcraft carb,not a Holley." I didn't know the Motorcraft ALSO has a power valve.THAT could very well be the reason it's running so bad under load. I took the power valve off the old carb,and plan to put it in tomorrow. With ANY degree of luck,that'll make it run like it should.

   It appears the master cylinder's the culprit that's making the Toyota brakes screw up;at $18.00 I can replace it next time something sells,making the brakes functional,if not fully "happy".

   I think we've narrowed down the Harley's "no-start" condition to stale gas. Apparently,today's Ethanol treated gas only has a shelf life of 3 weeks to a Month,and this tank's been full for a little over 2 months. I plugged a good spark plug into the rear cylinder plug wire and cranked it,and it sparks fine,so I doubt there's an ignition problem. It COULD still be a stuck float,but either way,the gas is the problem. I wonder if that "Stabil" gas treatment will refresh gas that's already past its code date.

   Speed

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   I think we've narrowed down the Harley's "no-start" condition to stale gas. Apparently,today's Ethanol treated gas only has a shelf life of 3 weeks to a Month,and this tank's been full for a little over 2 months. I plugged a good spark plug into the rear cylinder plug wire and cranked it,and it sparks fine,so I doubt there's an ignition problem. It COULD still be a stuck float,but either way,the gas is the problem. I wonder if that "Stabil" gas treatment will refresh gas that's already past its code date.

   Speed

 

Speed...Yup, ethanol could be the culprit on the H-D, though two months would be short time for any damage...The needle could be stuck in its seat.  Light tapping with a screwdriver handle at the float bowl will usually loosen the float needle.

Quick story:  My vintage Honda XR350R dirt bike set for over a year with no Stabil in the tank and "winter" (likely MTBE additive) fuel in the tank.  The dual carburetors each had clogged, with the primary carb's pilot jet low enough to be submerged in the fuel bowl.  The engine would not idle nor would it respond to mixture adjustments.

I dropped the primary bowl with the carb in place and sprayed carburetor cleaner directly upward through the pilot jet.  The jet would not clear out.  I eventually removed both carburetors (not a simple task) and rebuilt them with $20 (apiece) overhaul gasket kits from Honda, rather pricey for nothing more than O-rings and neoprene gaskets.  The pilot jet on the primary carburetor was so impacted with encrusted ethanol fuel that it was impossible to clean out.  No amount of soaking in caustic carburetor cleaner would help, either...You cannot "drill" through plugged jets, the brass will yield and cause the hole to elongate, which increases fuel flow and modifies the fuel mixture.

A new pilot jet (Keihin) and thorough carburetor rebuild and staging later, I learned not to leave "modern" ethanol or winterized fuel in the carburetor bowls.  I run the engine to stall with the petcocks turned off and the bike upright.  

Stabil does work within reason, though fuel quickly loses its volatility when stored.  In my experience, three months is the maximum age for fuel performance, and that's already a loss in performance.  I like to run the bikes down low on fuel before storing, add Stabil or equivalent, then run out the fuel in the bowls.

For our motorcycling and ATV/UTV forum members, I've copied this reply as a new topic and placed it at the dirt motorcycle section...

Moses 

Edited by Moses Ludel

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I decided if I was making the "new" carb similar to the stock carb,the main jets and metering rods/tubes would do it;in trying to get rid of its dislike for running under load,I thought maybe I should change the power valve to the one from the stock carb. I did that,and it runs HORRENDOUS. I drove it around for 10 minutes trying to get it to "clear its throat and scream",but it just never did. It was worse than with the power valve from the 302 carb.I know the power valve from the stock carb was good when I pulled the carb,dumped the gas out and put it on a shelf in the shop. I swapped it into the new carb,and you know  the rest. I didn't mess with anything else. It ran like the choke was mostly closed but it was completely open. I don't know how the power valve could be damaged in storage,but since I didn't change anything else when I installed it,what else could it be? I think I can order a new one at NAPA for around $8.00 (goodbye groceries),but I'll see if there's anything else that could be the problem before I do that.

   BTW-when I test drove it,I noticed the volt meter was showing 14.?? volts,so it LOOKS like the alternator's alternating again. (WTF??) I think I'm gonna re-name this truck "The Bermuda Triangle".

   Speed

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Okay,as described elsewhere,I changed the main jets and metering tubes,the truck ran relatively good,but very rich. I swapped the power valve from the stock carb thinking it was the problem and it went FAR worse. I decided it HAD to be the power valve was blown out so I bought a new one. from the time I left to get the part and the time I got home,it went from 45# oil pressure to 0 as I parked it here. I checked the oil,which WAS full right after the oil change,about 75 miles ago,and it was empty. I added three quarts I got for the Toyota,and it shows around 25#. I suspect there's a lot of gas in what's left of the oil. (Would severely flooding the engine with gas cause the oil to leave the pan via the combustion chambers or breathers? That would sure explain a lot-the loss of 3 or 4 quarts of oil,and 3/4 tank of gas in 75 miles,and all the blue smoke. At next possible opportunity I'll do another oil change.) Anyway,yesterday,I got the power valve changed out,also checked for problems with the float and needle-n-seat but they were fine. Wanted to test run it last night but the battery was too weak,so I put the charger on it and checked it about an hour ago. It fired right up,needed about 1/4 choke and ran GREAT. (I still think it has a burnt valve,but I can add that to my future expenditures list.) I'm not going to drive it though,until I get the oil and filter changed. It runs like it's still a little rich,but I'll have to run a tank of gas through it,read the plugs a couple of times,check the mileage before I'm sure. I guess this'll be where the "fun" starts-trying to fine-tune for economy.

   Speed

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I did the oil change on the BroncWorth last night;drained about 3-4 quarts of oil and about a gallon of gas out of the crankcase. Installed a new FL1-A filter,4.5 quarts of 20W-50 oil and a can of "Restore" oil treatment. I drove the truck around,running some errands,and it runs very well,and shows just under 50 pounds of oil pressure cold,about 35-40 warmed up. Has plenty of torque from idle on up,revs cleanly to where I chicken out and get off the throttle. (about 4500 r's) I did notice some foam in the coolant;I'll monitor the fluid levels and see if anything is  increasing or decreasing. Didn't smell burning coolant in the exhaust or gas/exhaust in the radiator. I can't drive it extensively because it's down to 1/8 tank of gas (with 79 miles since last fill up-approx 2.5 mpg!!) Expecting MUCH better mileage;it FEELS like it's still running a little fat though-is there a way to lean it out just a little from 1,000 rpm up without re-jetting it?

Regarding lifting the front end "just a little":

"The entire front axle needs to drop down as an assembly"

What I'm seeing is the front is developing a little bit of "VW squat",so what I'm looking to do is just lift it an inch or so at the springs.(Same effect as putting a stiffer torsion bar on a VW's rear suspension when you install a Corvair engine. Just makes the wheels stand upright again.) Standing back and looking at it,it doesn't look as bad as I thought;maybe I'll just have the alignment shop check the alignment and check it for parts that are terminal. I don't really want to go for a "Lift Kit"-I just want the front springs to pick up the nose about an inch or so,not messing with the pivot point.

   Coincidentally,the Toyota,s almost empty of oil,developed a leak in a heater hose under the intake manifold a few days ago,and the brakes are still being wacky. I drove it to Walmart for oil and filter for the BroncWorth,it wouldn't start when I was ready to leave,so I caught a ride with a friend. Had another friend take me,a new battery,gallon of coolant and a tow chain up there this afternoon;swapped the battery,filled the radiator and threw the chain in the bed and it fired right up. Drove it down to the traffic light and the brakes were pretty low. Got to the next light and they were just gone. Got the truck home and though the pedal was still low,they were dragging bad enough I had to use 4W-low range to back it into the driveway-rear wheels just spun in 2WD. I think it's about finished for a while. I'll try a master cylinder and brake fluid flush and re-bleed in a couple of months if I can get enough $$ ahead. (I ALSO need to "wash" the underside of the Toyota before I start any serious work  on it. I'm thinking about half a dozen cans of "Family Dollar" oven cleaner and a high pressure nozzle on the garden hose should do it. I'll just pretend I don't see the skating rink that'll make in the alley.

 

   Speed

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   I've decided to go with a 10si one wire 63@ alternator;bought one new from NAPA for about sixty five bucks,I'll install it tomorrow,since it's supposed to get up to 40 degrees with no snow or rain. It'll be just that much more wiring I can eliminate.

   I guess the only way to fix the start circuit power issue will be to find the wiring from the ignition switch,find the wire I need  and trace it out to see where it disappeared to. I fixed this same problem on my Fairmont by replacing one melted wire,but I don't remember what wire I replaced,and I don't know how close the B-II wiring is to the Fairmont's. That happened back when I still knew everything. 

   I've discovered the wiring diagrams in my Haynes manual are absolutely worthless to me. Most of the connectors,junctions,plugs and bridges are represented only by numbers,there's no code to tell what's what. Very sketchy color codes,and every component is represented by a box instead of a picture,and they're not located correctly in comparison to other components,so if you're not already familiar with the vehicle's wiring,it's near impossible to make any sense of them. Anyway,that'll pretty much take care of making the BroncWorth reliable. I STILL haven't had time to do anything about the throttle cable,but if there's time that might also happen tomorrow. (I notice it's 3:15 AM,but it's not officially tomorrow until I sleep and wake up.)

   Speed

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Speed...I rely on the factory shop manuals and their wiring diagrams.  For Ford F-trucks, I have the 1985 and 1993 models covered.  Is the Bronco II an '85?

Moses

Edited by Moses Ludel

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Mine is an '84,mostly. Like most vehicles its age,it's had some "creative" wiring done,and some mods done by accident. We're looking at approx. 10 days of cold,snowy weather,so I'm going to leave it as is for now. Today through Tuesday it's supposed to be above freezing for a couple of hours a day but I'd like a little bigger "window" than that,knowing I'll have to stop and warm my hands from time to time.

   Under and left of the steering column under hood there's a bundle of wires that show signs of melting at a plug;there are a couple of purple wires with white tracers that are pretty crispy,one is bare for half an inch  going into the plug. I've isolated everything and tried to seal 'em up with liquid tape,I can't get hands on 'em to tape or heat-shrink 'em. So far everything else seems to work okay except the start position ignition feed,so if that wire isn't purple w/white tracer,I'm not sure what the purple goes to.

   On a slightly different subject,I find it interesting that on GM stuff,you can't leave  your ignition on the run position (that's what I'm told anyway) with the engine dead or it smokes the module,but on my Bronco II it doesn't hurt it a bit-I don't even HAVE an accessory position on my ignition switch-I just leave the key on to listen to the radio while I work. I'm hoping the Dura-Spark II system also works this way.

Speed

Edited by Speed
Forgot a detail.

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