chevrolet21 Posted December 3, 2009 Share Posted December 3, 2009 Hi there I have a 1986 camaro with a 305 in it and am having a few problems with it. Originally was a tpi but now carby. For starters it seems to run hot iv replaced or reconded everything ie waterpump,radiator and hoses,water pump, thermostat and put an extra electric fan on it. It runs a 82degree thermo but temp seems to creep up to 100degrees even on a cold day and very close to boiling on a hot day.Any ideas? Also sometimes when the motor is warm it can be hard to start and sounds like like a flat battery but after a few winds it fires straight up? another question when i fire it up cold or hot or give it a quick rev from idle it smokes a black puff out but when running doesnt smoke at all and doesnt use any oil just wondering what is worn to cause that? Cheers for looking and any help is much appreceiated cheers Quote Link to comment Share on other sites More sharing options...
powershotnt Posted December 3, 2009 Share Posted December 3, 2009 The black smoke on start up is a pure sign of running rich. Had a 350 that did the same thing. I had a 750cfm carb on it(was that way when I bought it). No matter what I adjusted it would not fix it. Changed to a 600cfm edelbrock 4bbl and it cured it. I tried hotter ignition system(wires,coil and plugs). The only thing that worked was the carb change. Now as to the internals(cam/valves) other stuff I have no idea about matching those up to make it work. There are some guys on here that are incredible on making sure you have the right cam etc. Quote Link to comment Share on other sites More sharing options...
chevrolet21 Posted December 4, 2009 Author Share Posted December 4, 2009 Aw ok the carb is a holley 4brl with the number 4548 stamped on it if that helps any one cheers Quote Link to comment Share on other sites More sharing options...
turboboost Posted December 4, 2009 Share Posted December 4, 2009 If I recall right, that's a 450 cfm carb. Quote Link to comment Share on other sites More sharing options...
powershotnt Posted December 4, 2009 Share Posted December 4, 2009 I also had a "flat battery" problem in the past and I'm sorry but i cannot remember what it was. I assume your temps are celcius? I would flush the whole cooling system. Pull your spark plugs and look at them..are they really black and sooty? That is a pure sign of running rich. Have you tried adjusting the air/fuel ratio screws onthe holly? Should be 2 screws front and center lower part of the carb. Screw them all the way in gently do not bottem them out hard..just let them "touch" the bottom. I adjust 1.5 turns out and see how it runs. The max i have set mine is 1.75 turns out. I think he is right it is a 450cfm carb..should not be running rich. If that doesn't cure it try replacing the plugs or perhaps you have a weak plug wire. Good luck Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 5, 2009 Share Posted December 5, 2009 Make sure you have fully purged your coolant hoses for air. This is a major cause of overheating. Also, if you have not installed a new thermostat, do so. This may be a cause of the temperature running high. Some guys even remove the thermostat altogether, although I'm not necessarily a proponent of that and think of it as a last ditch effort. Air in the hoses or poor air circulation through the radiator is more often the problem. This site is well documented with fixes for this problem...just use the search function and you should be able to pull up quite a bit of information. Davy Quote Link to comment Share on other sites More sharing options...
chevrolet21 Posted December 6, 2009 Author Share Posted December 6, 2009 Alryty mucked round with the mixture screws on carby and with the screws wound out 1.5 turns it idles at 1500revs and i cant adjust the idler screw any less. so mixture screws are only wound out half a turn to keep the rpm down maybe mis timing now? Also replaced all spark plugs a year ago and are oily again so thinking the valve guides are probably worn rather than running rich? Quote Link to comment Share on other sites More sharing options...
hoov100 Posted December 6, 2009 Share Posted December 6, 2009 just a little fyi, thats a really small carb for a 305, but if you want to keep it, I would suggest rebuilding it, if you haven't already. Quote Link to comment Share on other sites More sharing options...
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