The 595 and 650 motors I have for my 1971 500L both use the 28 IMB carburetor. The carb has a fitting for a return fuel line which the 500 does not use. Can I just block off that fitting with no problems? Thanks, Ken

Hi Kalsig- yes- you can just block off the return fitting when fitting a 28IMB carb to a 500. Just remember that with 500's the fuel presure is adjusted by the thickness of the gaskets between the fuel pump and the bakelite spacer. If you find that it is flooding at idle with a good needle and seat and correct float setting you might need to add a thicker gasket to reduce the pressure- if you are running out of revs at the top end put in a thinner gasket. Hope this is of assistance, Damon

Thanks Damon, That helps a lot.