Nippon Denso Throttle Tightness

[Matthew]

I have an older Cummins 6BTA5.9 CPL 1928, ESN 45129316 with the Nippon Denso Injector pump. The throttle cable has always been pretty tight (i.e. hard/harder to move) than I felt it should, so, I decided to do a little investigation and replace what I thought would be a Teleflex/Seastar cable that was bad.  I was fairly sure the culprit was going to be the cable from the upper helm (fly bridge) to the lower helm since it was the longer cable and most exposed to the environment.    So, to diagnose, I disconnected the lower helm cable at the control lever from the engine.   To my surprise, the controls now moved easily at both the upper and lower helms… so… it was not the longer cable.    I reconnected the cable to the engine on the lower helm controls and then disconnected the cable on the engine at the injector pump.   I expected the tightness to return, however, it did not.  The levers moved smoothly and easily at both helms. It looks like the tightness is completely on the throttle of the Nippon Denso pump.   It has a large spring on it that appears to “assist” in advancing.   If you try to move the throttle by hand is it pretty tight to move and without the spring its really hard to move.   Is there any adjustments that can be made?   Is the spring “assisting” the throttle advance on the pump worn out and should be replaced?     What am I missing? Thanks -Matt        

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[Tony Athens]

Nippon Denso EP9 Throttle Linkage

The pic attached is what Cummins came up with to balance or assist the internal workings on the EP9 pump.. Best to take it apart, lube all, figure out how it works and then you can decide where the issue is.. It’s just about always related to linkage rust, an old cable/binding, etc.   Nothing scary when working on it.

[Author]

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