Cummins NTC 350 Fuel screw Question?
 

Howdy,

I have a question about the fuel pump that is on my 1971 NTC 350 cummins engine.

The problem I have having is I cant find or know where the fuel screw is on the pump. I have seen three different styles of pumps for this engine. (there might even be more) two of which have the little ball you drill out of the throttle shaft to get to the fuel screw. The pump i have seems to have a solid shaft. No ball at the end of it. What Am i missing??

Here are some pictures. No pictures?? Still editing post!

Thanks for any help!

Most common pump for the NTC 350 that I have seen. You can see the ball in the end of the throttle shaft.

Pictures as said. Ran out of time to edit post. Sorry I cant get the pictures to show here. You will have to click them. Thanks

Most common pump for the NTC 350 that I have seen. You can see the ball in the end of the throttle shaft.

This one is more like my pump BUT as you can see it has a fuel screw. The ball has been drilled out already.

And here is what my pump looks like. The end of the shaft is flat. no ball to drill out. am i missing something? Is there a cover that slips over the shaft?? I am at a loss without tearing into it. But i really dont want to just do that unless i have to.


Any help would be great. This things got to have a fuel screw. How else would they get it to specs??


Thanks again.

http://i1129.photobucket.com/albums/...psqckwuunv.jpg

This style pump needs to be done by a shop, the pressue is adjusted from the opposite end of throttle shaft so it has to be removed.

Though looking at that I don't even believe that pump is setup for the same rotation as a 855. Fuel inlet port should be towards outside of pump on right hand pump models.

The throttle shaft can be changed to external adjustment like the other similar style pump is.

Thanks! I appreciate it. I looked all over the internet and could not find any answers for my questions. The pump there in the picture is not my pump. But one that has the same style throttle shaft. I might just have to switch the pump out for the nicer style one.

You say the fuel screw changes the pressure?? I was under the impression all that screw does is let the pump move more fuel, And that the button in where the governor and idle screw is is what controls the pressure? I have a 300 PSI gauge that I was going to use to check the pressure as i did different things to it.


Thanks again for the help!

Well yes it does allow more flow, but trying to shove that extra flow through the same spot increases pressure.

Ok That makes sense to me. I guess for now all I am going to do as long as I have the pump I do, is just change out the fuel button.

Thanks again for taking the time to answer my questions!