Replacing M35BC fuel pump

[John Langford]

I just replaced the mechanical Facet cube fuel pump on my M35BC with the contemporary Facet solid state cube fuel pump FAC 40105. It was an easy exchange. The replacement pump was exactly the same size as the original so the mounting holes on the engine could be reused. The fittings connecting the fuel line at both ends of the pump were also reusable. The only additional work required is to add a 3 amp inline fuse. Assumedly the solid state pump is more sensitive to electrical spikes than the mechanical one. I lost almost no fuel in the exchange so that running the pump for a few seconds before starting up got rid of any air in the line if there was any. I have subsequently been for a cruise and the pump performed flawlessly.

My original pump had developed a very slow leak from within the pump at the input end. 

Be sure you buy the new pump from a reputable dealer. I used Aircraft Spruce that supplies equipment for planes. The service was excellent. There are cheaper knock offs of the pump around. The price should be around $50.