Re: 115 hp johnson fuel prob
Those diaphrams simply move back and forth. There are check valves in the VRO that close when the diaphrams are in one direction, then open when in the opposite direction, thustly drawing the fuel/oil into the pump.<br /><br />Pumping the fuel primer bulb..... in effect you are acting the part of a manual fuel pump. If anything was wrong between the primer bulb and the fuel supply (leaks etc) where air could enter the supply line, by the same token fuel should be leaking out at that point and would be obvious by sight and/or smell.<br /><br />You've said nothing about the fuel primer bulb going flat, and the fact that you can pump and have the fuel bulb return to normal indicates that there is no fuel restriction.<br /><br />Apparently from what you've said about the Pulse Limiter, you've also checked the pressure line from the crankcase to the VRO pump for breaks, leaks, etc. I assume that there are no fuel leaks anywhere or you would have mentioned them.<br /><br />I also assume that the engine is not knocking due to any kind of powerhead failure.<br /><br />This leaves three possibilities I would think. Either a reed plate (leaf valve) pertaining to the cylinder that operates the VRO has broken, which would eliminate the power (pressure) needed to operate the VRO (possible but the engine would be running on three cylinders), or the related engine piston has blown apart which would also eliminate that needed pressure (unlikely), or the VRO is faulty at some point (most likely).<br /><br />If the VRO loads the carburetors up with pure oil (not a mixture) when you stop pumping the fuel primer bulb and the engine is allowed to run out of gas, that proves that the engine's crankcase pressure (reeds, piston, gaskets) is okay. This indicates that something is wrong with the fuel side of the VRO (diaphram, check valve, something). Let us know what you find.
