December 9, 2023

200 pumper

I have finished installing a Perry pump in the standard (unpumped) O.S 200 FS that will power my new Laser F3A model.  As you can see the pump is hung on to the engine mount, adding minimal weight and is a compact installation that I’m very happy with. 

The fuel line that pressure feed the pump is routed through the engine mount, as straight and short route as possible. The tap is a 4mm pressure tap. Tapping the crankcase is tricky- there is no clearing on the inside and the cast backplate is VERY thin. I did my best so I hope it’ll hold. The crankcase is in fact already tapped on this engine. Not visible, but just above my pressure tap is a cast hole that has a pressure feed going into the carburettor. No Idea why, but I hope there’s enough pressure left for the pump…

The whole assembly including pipe. The Hatori header requires some work to fit this engine. The exhaust port is deeper than on the 200 EFI so I needed to cut a big spacer from a plumbers copper joint in order to be able to tighten the header nut. I also had to drill and tap the top to accept the screw from the header fastener. Presumeable this fastener is to prevent the header from cracking from soft-mount vibration.

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