Engine intermittantly running rough

[luvrbus]

What is the size of the inlet on your pump ? and you cannot use the filter that come with those pumps unless you are into changing the filter every week you need 3/8ths inlet and out for  the min.   

[dtcerrato]

What is the size of the inlet on your pump ? and you cannot use the filter that come with those pumps unless you are into changing the filter every week you need 3/8ths inlet and out for  the min.

All the lines are 3/8" ID or larger. The engine runs really smooth & steady @ no load. The by pass really prioritizes the OEM feed to the engine mechanical pump - anything different & the pump pressure decreases. It's all good now & ready for a few day road test (we hope)!

[luvrbus]

The check valve on the suction side causes problems with restrictions too I move those to the return side per a Detroit service bulletin issued in the late 70's 

[dtcerrato]

Thanks! You just added an item to my list.

[someguy]

"The pump is a high volume pump ($400) so no cheap one."

It's a myth that diesel engines need a huge fuel pump.   A 6-71 makes about 200 HP.   At a BSFC of 0.40 (which is high), it needs 80 pounds per hour.  Diesel fuel weighs 7 pounds per gallon, so less than 12 gallons per hour.

2 stroke DDs have a gear fuel pump built into them.   About all they need is unrestricted suction and they work.  In a truck tractor application the fuel tank pickup is ~ 2 feet below the engine when the tank is empty.  In industrial applications, the tank bottom can be further down than that. 

[luvrbus]

2 strokes only burn about 1/4 of the fuel the fuel pump supplies the rest is used for cooling the injectors a 2 stroke should return .9 GPM.I never saw a built in fuel pump on a 2 stroke before you learn something here everyday.I have seen the pumps driven off the blowers and fuel pumps driven from the auxiliary drives but never a built in fuel pump before   

[someguy]

I meant the pump driven off the front drive.   Built into the engine.