Re: 1985 Johnson 90hp VRO V4
Can i replace the fuel pump with a electric pump with a fuel regulator if so what should the psi be to the carbs.
You just opened a huge can of worms without even realizing it. Many on here will say don't ever never ever use an electric fuel pump on a 2 stroke outboard, and with some valid reasons. The fuel pump will keep running when the engine stops and if a carb float is stuck, for instance, you can have a puddle of fuel in your engine cowl very quickly. In the case of any kind of upset or accident the fuel pump will likewise keep running.
Guys that race outboards use electric fuel pumps, the race santioning groups mandate that the fuel pump relay be wired through the safety kill switch.
There's a fuel pump relay that senses tach pulses and shuts off when the engine is no longer running, it was used on VW's in the early 80's. It's still available at parts stores, VW part number 321906059G.
The pump output pressure should be around 4 to 5 psi.
If you're not comfortable figuring out how to do the wiring to incorporate these safety features (or know someone who is) you probably should stick to a mechanical pump. Even with the safety features incorporated you have to realize that the fuel system will be pressurized and a leak will be pumping fuel out instead of sucking air in, so you need to be meticulous in your plumbing and do frequent inspections.
