Giorgio Ancona Posted August 1, 2022 Share Posted August 1, 2022 Hi everbody , my 1955 GMC 100 with the original 287 Pontiac engine and equipped with a two barrel Bendix WW 23-106B has running problems . Over 170-175 degree water temp the engine stops running during traffic jam only , I got this problem this year and I renewed the ingniter plugs the ignitor leads and installed a new MSD Blaster 2 coil but nothing helps. When I open the hood its very hot , could it be that the fuel has gas bubbles and therfore the engine stops? What I found is a leak at the throttle lever of the carb but it is leaking when the engine is hot only. Does anybody has an idea or does anyone knows this problem? Giorgio Link to comment Share on other sites More sharing options...
41 Su8 Posted August 1, 2022 Share Posted August 1, 2022 Possible vapor lock. 1 Link to comment Share on other sites More sharing options...
carbking Posted August 1, 2022 Share Posted August 1, 2022 This link will probably explain the leak: Leak by throttle shaft As far as the shut-down: when this happens, test to see if you have fuel at the carburetor, and spark at the plugs. Jon. 2 Link to comment Share on other sites More sharing options...
Giorgio Ancona Posted August 2, 2022 Author Share Posted August 2, 2022 Thanks Jon for the link. Spark at the plug I checked already at the last shutdown but fuel at the carb I will check next shut down. Link to comment Share on other sites More sharing options...
Giorgio Ancona Posted September 6, 2022 Author Share Posted September 6, 2022 After changing the ignition coil to MSD2 and all spark plugs to AC Delco R45S I thought the problem is gone but sunday it happens again four times. What I found out is that it happens during braking while driving down a hill (bridge) and when I did a hard right and immediately a left turn( in a roundabout traffic) the engine goes off. From my point of view it seems to be a fuel problem but the fuel tank was 3/4 full and the fuel filter shows fuel inside. The last time it happened it took very long cranking before the engine starts again. Link to comment Share on other sites More sharing options...
m-mman Posted September 6, 2022 Share Posted September 6, 2022 You can’t always trust an old metal fuel line. Had a 60 Edsel that was constantly “vapor locking” (engine shut down) but turns out there was a cracked fuel line. perform a vacuum test on the fuel line. disconnect both ends (tank & pump) plug one end (hose and bolt) Attach hand vacuum pump at other. (Having the little catch can in the vacuum line is good) Then suck down a vacuum. No fuel should enter the catch can and it should HOLD a vacuum. If fuel comes out then air is coming in. If it won’t hold a vacuum then air is entering the line. If air can enter a fuel line the fuel pump can’t draw it up. Reasons a fuel line won’t hold vacuum? Cracks and rusty pin holes. I have never been successful finding these defects with a pressure check, but a vacuum check is extremely sensitive to these issues. 1 Link to comment Share on other sites More sharing options...
Giorgio Ancona Posted September 16, 2022 Author Share Posted September 16, 2022 Thanks ,I will check it when I am back in Germany. I am in the states now and I tried to buy a fuel pump at Summit racing in Arlington but they are able to tell which one fits. Link to comment Share on other sites More sharing options...
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