The last 3 times I have driven my truck it cranks and runs great, but the longer it runs the lower the idle speed. I put a lock nut on the idle adjustment screw and checked the cables. When the engine is cold everything works as expected. If I stop and then try to restart the engine before it cools, it's hard to start and doesn't idle fast enough to keep running. Once it cools a bit, it starts and idles properly.
Looks Like Time to do a comprehensive Tune Up regimen beginning with a HOT valve adjustment ~ yeah , yeah I l know : your fingers will get burned and have scars like mine but that's the deal with Old Trucks (Cars , too ) . ALL/U] of my carburated engines loose idle speed in the heat . As I like the hot idle at or below 700 RPM's , I get intermittent missing when it gets really hot . As always , I suggest going back to the basics before touching anything else even if you just did it and you're sure it's all fine .
Oh , Yeah ~ The thing where it's hard to re start after a hot shut down is because to - day's crappo foo-foo ' motor fuels ' boil out of the carby and flood your engine making it hard to re start and then near impossible to keep idling for a few minutes . The Technical Term for this is " Fuel Spewing " and is one more reason carbys went the way of the Dodo Bird ~ for maximum efficiency and lowest possible exhaust emissions your engine needs to run at or above the boiling point of water , this upsets the delicate balance a carby needs to have to work properly ~ . I recently did a major tune up on a '59 Met 1500 and even in the blazi8ng sun it hot started *instantly* and idled perfectly . I cleaned up and grabbed some water , began repairing a bad lighting circuit on another car and the tune up car's owner came over visibly upset saying I'd made it worse and now he couldn't start it to go home again (I guess the FREE part had slipped his mind) so I walked over & popped the hood and asked him to try starting it so I could listen , hear & feel what was going on ~this 62 year old noodle began pumping the throttle even before he cranked it , on a 95? F day ! no wonder it couldn't start : he'd flooded it before it ever had a chance then he continued to pour raw fuel into it by frantically pumping the accelerator pedal as he cranked away ~ I held the throttle wide open and told him to crank it , in 10 seconds it roared to life . belched out some black smoke as the flooded fuel burned off then I released the throttle and it idled perfectly again . How an Old Man who grew up on carbys , could ever not know not to flood it I'll never understand but here's some basic starting drills for cold and hot engines : When cold , pump the throttle once or twice to the floor each time then release it and don't touch it as you're cranking the engine , as soon as you hear it begin to fire , feed it a little bit of throttle and it'll keep running . When hot , you'll have to experiment to see what your particular engine and state of tune prefers ~ some like you to crank it but *not* touch the throttle , others will want you to open the throttle a bit as you crank it . One thing all engines , fuels and tunes have in common : you must never , EVER pump the throttle as you're operating the throttle ~ this guarantees harder starting , always, every time , no exceptions . Understanding and practicing this is how I can jump into any old vehicle and it always starts easily for me .
Thanks for the help Nate! The starting routine is what I use, pulling out the choke, when it's not been cranked in a few days. When warm, no choke and NO pumping.... I do recall that some carb engines called for the pedal to the medal while cranking if the engine flooded, but most did not. It's been about 10 months since the valve problem you steered (no pun) me through. Probably have put less than 500 miles on it since then. But like Nate says--- get out the screwdriver and start with them valves...... Thank you Nate; always great to have your help!!
Fuel Additives AKA : Snake Oil ! . I really only approve of three : Sea Foam , Techron and Sta-Bil . Once in a while you'll get those intermittant misses coming out the exhaust pipe @ idle , this is called " Shooting Ducks " and is the valves sticking to their seats . If you get this , add 3 Oz. of Marvel Mystery Oil or ATF to a FULL tank of fuel and see if it helps . The trouble begins when you don't use all the fuel and top it up then add more Snake Oil , then the mix is too much and causes gumming in the carby..... In general I do not use / recommend fuel additives in Gasoline engines in spite of crappy foo-foo " motor fuel" junk .
No additives! Look here!http://ampcolubes.com/ This will solve the problem and they are so easy to install! I have installed the simple system in my truck aswell and it functions very well. I use Marvel oil and I do not use any additives. Ampco tells you why you should`nt. Martinius.
Well, it turned out that the problem was the ballast resistor. While checking the dwell and timing, the little sucker started smoking, checked the resistance and it was 2.2 ohms--ouch! No telling how much resistance it was when hot! Anyway, thanks again Nate! What's the favorite electronic replacement for the points? I see several recommending the Pertronix kit and coil. Anymore favorites out there? Let me know the details on the coil and whether or not the existing wires and plug gaps are good to go with it(more spark = more gap is the rule isn't it?) Thanks again gentlemen-- I know, I know, I used the term loosely....
This is why I like the pertronix and use internally resisted coils. I hate those ballast resistors and their intermittant problems.
Ignition Upgrades In my worthless opinion , the Pertronix ' Ignitor ' is the way to go with stock distributors . No need to buy a fancy-schmancy coil , just read the instructions and then TEST the impedance of the ignition coil with no wires connected to it , make sure it matches *perfectly* for the system you bought ~ they're very specific in the instructions . Once you have any sort of Electronic or breakerless ignition ,you don't need any ballast resistors , calibrated resistance wires etc. atall . just buy the direct fit kit to match your engine's power supply be it 6 or 12 volts . Discard any by-pass , ballast resistor , calibrated power wire etc. jazz ~ cut it out and toss it . Simply ensure 6 or 12 VDC direct to the coil and use some decent wire like 10 Ga. not the original 14 Ga. crap as it needs to get not only a full 12 volts but easily pull 10 amperes when it's hot in Summer or flooded etc. I didn't want to re do the underhood wiring harness on my current '69 C/10 so I added a cheapo cube relay to the firewall by using the engine to firewall ground strap's screw then I wired the calibrated resistance wire to kick the relay and ran a short 10 Ga. power wire from the hot lead on the starter to the relay , from the switched side of the relay to the coil and Lo ! my oil chugging engine now runs like it's in good shape when it used to oil foul the plugs every 150 ~ 200 miles . Increasing the spark plug's gap , drives the coil to it's maximum output , not the other way 'round . So , if you're running a stock 6 or 12 volt ignition with points , open the spark plugs up to .035" and marvel at how much power you <magically> get , how much better it idles and starts too . If you're running a Pertronix , open the plugs up to at least .045" . If you have a V-8 , V-6 or newer I6 engine , be smart and go buy a factory HEI dizzy and drop it in , the free power will blow your socks off , you can run .070" + spark plugs gaps on stock HEI ignitions . Anything is better than breaker points by orders of magnitude . Don't get sucked in by B.S. adverts for " 40,000 + volts !! " Flamethrower coils as any good quality ignition coil does that but only when the big plug gaps force it to . Upgrading the ignition is the single most dollar value up grade you can make . It always makes the engine run better , even when totally worn out and , it doesn't beat up on anything unlike wild cams and big carbys do . Once you're nearly set and discover the old coil doesn't match the impedance , don't panic and grab the Jegs Racing Catalog , instead grab your $5.00 Harbor Freight analog Multi-Meter and go looking at the old junkers lying beside the road , in the ditch or lake..... test every coil you find , take it home and clean it off really well , spray it with engine starting fluid (Ether) and invert it in the plastic top of a Foo-Foo can , then spray paint it the color you think looks best . Add decals to match and you're golden and $aved $ to boot . Or , realize I'm just another Internet Troll who never drove , worked on or even looked at any old vehicles and go buy $350 worth of cheaply made shiny chrome crap made in China . Your call , have fun no matter what you do .
Thanks for the excellent inputs Nate. I had not thought about the 10 gauge wire, excellent input. so, it's more gap = more power to get across the gap! Your posts make for excellent info and good reading; greatly appreciate you sharing your expertise. I do recall that you once said "it's worth what you pay for it"! But I can assure you it has tremendous worth to me and I have used a great deal of it over the years. Thanks again! Put-Put
It is always good to know at least one cranky, opinionated old timer when you keep an old vehicle alive. They can tell you how they dealt with the damn things when they were new and the internet wasn't handy to order whatever you think you need. Thanks, Nate!
Grumble , Mutter , Complain......... Hey you kids ! GET OFF MY LAWN !! . Eh , I mean : why , thank you fellas .
