Putting a new impeller in a 52′ Evinrude Big Twin. I dont see the little trapdoor to disengage the shift linkage like in the later models. Whats the protocol here? It starts fairly easy but needs to be returned to dual-line tank. Seems to be having fuel issues and I think it’s cooler the original way. Thanks for any tips. Got a new lower for my 57′ Fastwin and plan to be on the water soon testing out my 2-blade prop so the fever is getting to me. My garden has been keeping me too busy to do damn near anything this year!