Rochester 1958 carb rebuilt last summer ran fine, ran fine this summer.Got on high way for 50 miles drove fine at difrent speeds,got off high way died out at idal.The idal was very low picked up idal to normal runs fine.What is the cause of my low idal problem, it ran that way for a year no problem.Any ideas what is going on.Thanks
Carb? Hey there Sounds like a mixture issue petrol & air. I`ll suggest you check your petrol quality , petrol and air filter, sparkplugs and contact point in ignition and insulator. Sometomes waterdamp in the petrol makes the engine reacting like this as it is`nt combusting fuel but damp . How does it run stationary when engine is warm ? Martinius.
Has the idle screw backed off? The're prone to doing this if the spring gets weak. If the throttle is working pull it out a tiny bit to hold a faster idle and if this works then it's almost a sure bet the screw has backed off.
I would pull the choke out...if it ran better...ck if fuel filter is stuffed with gunk...if not just a couple of months ago, I took the top of the carb off(in the field, literally) and after spending a couple of minutes getting my old eyes to focus, I saw a piece of gunk in the jet...??? Blew it out....and it has been running since. rod
Idle Oddities Look at the phenolic insulator between the carby and intake manifold ~ they often get tiny cracks that affect the proper idle then , when you're driving along , they shatter and you're stuck . New ones are only$5 , be sure to match 216 or 235/261 as they're different . NO GASKET between the insulator and manifold This is easy to test with a Foo-Foo can of engine degreaser or brake cleaner , starting fluid etc. BUT NEVER CARBY CLEANER as carby cleaner attacks and destroys this part . I assume you've recently checked and adjusted the valves ~ unless they clatter , they're out of adjustment and tight valves cause idle troubles . Then remove the spark plugs and ensure they're gapped to .035" using a wire typ gauge as too narrow plug gaps cause poor idle . Then check & adjust the timing using the $30 inuctive timing light sold @ OReilly's , PepBys Et Al . ball on pointer @ idle in the little window just above the starter motor . Do these things BEFORE touching the carby ! . I assume you do have a clear plastic paper fuel filter right before the carby ? . if not , go get one right away . You can use those glass bowl ones too if you want to be a purist .
