300/440/550 carb help + other mod

[xXxjs440xXx]

Anybody know what kind of carb this is? I ask because no filter came with it, any ideas on replacements or custom filters applications? looks like it is missing a screw as seen in the last picture, is this needed? Also what might this large black button be? The line goes to a small part with attwood on the lable, handle mounted bilge pump?

Thanks

 

[portnpolish]

Looks like a 38MM Mikuni which would be true if it's a 440 or it could be a 44MM Mikuni if its a 550. The adapter on top is for a K&N Filter. As to the missing screw - that is where the choke was originally. Usually people use this for the Primer port when they install a fuel primer. Looks like yours is blanked off with some black silicone.

 

[portnpolish]

The big black button looks like a kill switch off of the first generation 76-80 year model standups. Guess you'll have to trace the wires or give it a bump to see what it does. Good luck.

 

[Mr Bojangles]

Im sure its a 38 since its a 3 bolt, the 44 had 4 bolts on the top if I am right. And thats a old stop switch off a old 400, some people used them as bilge pump switches, but they are only momentary, so you have to hold it for it to be working