Perkins series 40c 497 cc idle problems

[catpower]

I have fitted a Perkins diesel engine on a Honda Motorcycle. It was built for constant 2800 rpm, which I adjusted to 3600 rpm. The motor runs great until it comes up to operating temperature. Then if you let it idle for any length of time it is slow to take off. You increase the throttle and it slowly increases in rpm. Since the motor was built for constant rpm and I am using it for variable rpm, could it be there is a missing part of the governor mechanism needed for variable rpm. I have not been able to get any help from the Perkins dealer. In fact they didn't like the fact I had installed one of their engines on a bike.

[dethmachinefab]

Ive found when my battery begins getting low the shut down solenoid begins to close and limits throttle input. Is it charging at idle? My 3 cyl needed a smaller alt pulley because it was not ment to idle so slow.

[catpower]

I have mechanical fuel shut off, I removed the electrical shut off. I am beginning to believe it is not temperature related. It seems to have the problem anytime I ride for very long periods of time at max throttle. Then when I stop and let it idle for any length of time it does not respond to the throttle increase immediately. Thanks for the reply to my question.

[dethmachinefab]

How is your fuel system set up? Lift pump,filters,return, etc? Pulling a vac on a ventless fuel tank possibly?

[XLerate]

As I just posted in another thread where a somewhat similar problem exists: be sure that the return line for the injection pump is free flowing and of sufficient diameter to hande the quantity of fuel, with no kinks or extremely sharp bends. A restriction there can cause system to build too much pressure in the return line when the injection pump puts out far more fuel than the engine consumes. Strangely enough this may cause either a rich or lean condition depending on system design. Whatever, the return line is absolutely critical to proper operation.