5 Star Rising Posted January 30, 2010 Share Posted January 30, 2010 Gotta 73 240 i bought as a project.. I had the flat top crappy carbs on it and It would take a can a starting fluid and about 10 minutes of trying to start the car before it would start... After it would warm up it would run but really crappy.. So I did a swap with a round top complete swap off a good running 72 240. Now I have kind of the same proplem with the round tops. I have an electric fuel pump hooked up to the stock wiring and relay (which could be intermittantly faulty). Its like the carbs are starving for fuel but there is plenty of fuel going into them and preasure, but if you spray starting fluid into the carbs it will start right up then die out after it burns it up. Yesterday I started the car cold with out starting fluid but it took 3 full minutes to get it running. It would turn over for along time then start like it was running on 2 cyl, I had to feather the throttle to bring up the rpm and hold it there till it warmed up a little then it would idle.. Any advise as to what could be going on here? Vapor lock maybe? tank issue? HELP Quote Link to comment Share on other sites More sharing options...
BURLEIGH Posted January 30, 2010 Share Posted January 30, 2010 check your PCV and any other locations that could be leaking air. You likely have a vacuum leak somewhere or as you state, are not getting enough fuel. Clean your float bowls and then work your way back to the tank making sure all the lines and filters are free of debris. Once you get it running and able to idle on it's own, take some carb cleaner and spray it on the outside of the carbs all around the throttle shafts and other locations on the intake that could possibly be leaking. If it starts to die when you spry around something then that is where your leak is... Post up a pic of your engine bay, we may be able to spot something out of place if that is the case... I have seen quite a few things that were not right about SU's that someone had unknowingly done... Good luck! Richard Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted February 4, 2010 Author Share Posted February 4, 2010 Well I got the car running ok from a cold start. After adjusting them alot It helped the car start and idle. I noticed the eng rpm will raise when I spray carb cleaner on or near where the throttle linkage rod enters the side of the carb. This happens on both carbs... This is my first time dealing with these round top carbs.. There is still a small miss when idling.. How do I clean out the bowls? also is there a standard procedure when tuning and adjusting these carbs? Like "3 turns out and back off 1/4 turn or something? or are these carbs all different"? what about the idle adjust at the bottom of the carbs? they are pretty touchy Quote Link to comment Share on other sites More sharing options...
shika805 Posted April 15, 2010 Share Posted April 15, 2010 this was my problem too with my car. have you checked your pistons in the carbs? do they move fairly freely up and down? timing could be the issue also for the rough idling, gaps on the spark plugs?? is your electric fuel pump assisting your mechanical fuel pump or are you running straight to the engine? The issue with my car was that the mechanical fuel pump was causing restriction to the carburetors. Once i connected the electric fuel pump directly to the fuel line, i had no problem with fuel starvation. Quote Link to comment Share on other sites More sharing options...
rejracer Posted May 14, 2010 Share Posted May 14, 2010 I find the following reference to yield the best results with minimal tools: http://www.gerull.nl/mg/technics/carb/carb_tuning.html Quote Link to comment Share on other sites More sharing options...
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