iivydriff Posted November 4, 2013 Share Posted November 4, 2013 Ive got an old 74 model Autocar. It has a Super 250 Cummins in it. It ran like a top then I parked it. It has set for several years. Ive been trying to get it fired up I need to sell the ole girl. ive made sure its got fuel to the pump. But im at a loss of what to do next. It does sound like its hitting on one cylinder. It will smoke when turning it over. Do I need to bleed the fuel somewhere on top of the engine? It has the old internal fuel lines. There are two plugs in the front of the front head. Could I pull one of the plugs out and make sure fuel comes out at that point. The lower plug should bleed the incoming fuel line. The upper plug I I assume is on the return line. I know these old engines are rare, hoping to find someone to help me out here. Ive did all the basic stuff drained almost all the fuel added new fuel. made sure its all primed up all the way to the pump. It will hit a little bit, but I just need to know if I need to bleed somwhere else that Im missing. Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/ Share on other sites More sharing options...
KECorbin22 Posted November 5, 2013 Share Posted November 5, 2013 Test your fuel shutoff solenoid on top of fuel pump, should be getting 12 volts, on some models there is a override thumbscrew, in front of the fuel shutoff, turn in all the way, if engine starts the only way to shut down is by turning screw back out. Do not take out the two plugs on heads. I got more ideas if that doesn't do it. Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215087 Share on other sites More sharing options...
b61mack Posted November 5, 2013 Share Posted November 5, 2013 Ive got an old 74 model Autocar. It has a Super 250 Cummins in it. It ran like a top then I parked it. It has set for several years. Ive been trying to get it fired up I need to sell the ole girl. ive made sure its got fuel to the pump. But im at a loss of what to do next. It does sound like its hitting on one cylinder. It will smoke when turning it over. Do I need to bleed the fuel somewhere on top of the engine? It has the old internal fuel lines. There are two plugs in the front of the front head. Could I pull one of the plugs out and make sure fuel comes out at that point. The lower plug should bleed the incoming fuel line. The upper plug I I assume is on the return line. I know these old engines are rare, hoping to find someone to help me out here. Ive did all the basic stuff drained almost all the fuel added new fuel. made sure its all primed up all the way to the pump. It will hit a little bit, but I just need to know if I need to bleed somwhere else that Im missing. On top of fuel pump is a fuel switch, try turning the switch to manual ( in is on) see if that helps. Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215088 Share on other sites More sharing options...
iivydriff Posted November 5, 2013 Author Share Posted November 5, 2013 On top of fuel pump is a fuel switch, try turning the switch to manual ( in is on) see if that helps.Ok I will look at that when I get a chance. Dont recall seeing any kind of switch there, but that doesnt mean its not there Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215144 Share on other sites More sharing options...
iivydriff Posted November 5, 2013 Author Share Posted November 5, 2013 Test your fuel shutoff solenoid on top of fuel pump, should be getting 12 volts, on some models there is a override thumbscrew, in front of the fuel shutoff, turn in all the way, if engine starts the only way to shut down is by turning screw back out. Do not take out the two plugs on heads. I got more ideas if that doesn't do it.Ok will look into that Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215145 Share on other sites More sharing options...
blackdog2 Posted November 5, 2013 Share Posted November 5, 2013 ITs a knurled thumb screw about 1/2 dia. Quote Ed Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215147 Share on other sites More sharing options...
fifth wheel Posted November 5, 2013 Share Posted November 5, 2013 I had a similar situation a month ago, the filter screen on the pump needed to be cleaned. It is under the slotted plug. If not that a few injector plungers could be stuck. FW Quote Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-215156 Share on other sites More sharing options...
thomastractorsvc Posted November 14, 2013 Share Posted November 14, 2013 So what did you find out? Was it the filter screen or something else? Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/33377-cummins-super-250-need-help/#findComment-216610 Share on other sites More sharing options...
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