Case 450 starts then dies.

Ray

Well-known Member
I have a case 450 diesel dozer around a 1973 model. It can set over winter and start instantly , but will die 30 seconds later. It will crank,but no start. I usually nurse it with a little starting fluid . If I keep it running for a minute or so it will keep running. I’m assuming it’s loosing it’s prime. Would it have a fuel pump someplace to get the fuel to the injection pump?
 
Xs two what CaseNutty said, if engine runs OK WITH the two screw timing cover loose allowing fuel to leak out, but dies with the cover tight, that confirms the injection pump needs repair. DO NOT knock out the return fitting restriction ball and keep running it, or you WILL soon wreck the pump by seizing the hydraulic head and breaking the drive shaft. I see that too often on pumps brought in for repair..
 
From your clues, it seems that air is drawn into the body of the injection pump WHEN IT IS STOPPED but not when running----- and not during the winter. Is fuel level in the tank a factor?

I am not familiar with the 450 but my 1170 is the same vintage so you probably have the Bosch inline fuel infection Pump. Is the bottom of the 450 fuel tank lower than the body of the fuel injection pump? If so and when the fuel level is low, the fuel level could be creating a slight vacuum at the supply pump.

Vacuum tends to pull air into the system if there is a leak to the outside. The supply pump has check valves that should prevent vacuum from getting into the injection pump body. But if the check valves are worn a little and not holding 100%, then the vacuum reaches the input shaft seal. A weak seal could allow air to be drawn in.

Before dissambling the system, I might add fuel and bleed the system using the manual transfer pump and the bleed screw provided.
 

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