Newbie here, trying to get sons 69' Fastwin to run. It does not want to start w/o lots of ether in the cylinders, then will not stay running. The electric starter will spin it over until it kicks once then it struggles to crank it. It is also very hard to pull start. W/O the plugs, it spins easy. We have replaced the fuel pump, rebuilt carb, all new fuel lines and fresh gas, new plugs and points. The spark is very good (white color). Where do we look next?