fuel problem 90hp Evinrude V4

[d_glover25]

I just replaced all the carb gaskets and hooked a new external tank and new fuel line to my 90hp outboard that was sunk. Cleaned out the cylinders and replaced all gaskets. Now it wont hold pressure in the bulb when running and will not idle. I can start it and take it to about 2500 rpm and it will stay running but when I adjust the idle screw it runs at a correct idle for a few seconds and then putts out. I would guess that its sucking air from somewhere but I cant find it and none of the lines or carbs are leaking gas. Any suggestions on where I should look or what to check. The bulb stays hard when the engine is not running.

 

[Big Keepers]

Re: fuel problem 90hp Evinrude V4

You need to find the air leak. It could be the check valves in the primer bulb, it could be the fuel pumps, a crack in a line, a bad connection somewhere. I'd say perhaps its the fuel pumps or maybe even the pulse hose that connects the fuel pumps to the crankcase. Try checking the vacuum and pressure on either side of the fuel pumps. I'd be surprised if that isn't your problem, or one of them.

 

[Walker]

Re: fuel problem 90hp Evinrude V4

Its perfectly normal for the bulb to get soft while running. If it gets hard when squeezed before starting and it doesn't collapse when running then I'd say that the fuel lind/buld from the tank to the fuel pump is OK