Re: Vro pump, how to check
The VRO is both a fuel pump and an oil pump - it is operated by an air motor which uses a diaphragm and rectifier valves to convert crankcase pressure and vacuum pulses into motion for the pump's 2 chambers. The most common failure in a VRO is the air motor diaphragm, when it fails, the pump doesn't work - period. It won't pump fuel or oil and the motor doesn't run - a motor that can't run, won't blow up. The unit can and will pump water. Although it has a "no oil delivery" alarm it cannot tell what it is pumping. In fact, its still the only oil injection system on the market that features a "no oil" alarm. Therefore, checking the oil reservoir for water intrusion occassionally is a good idea.<br /><br />The other failure I've seen is the seal on the oil piston - when it goes it usually causes the unit to over oil. It can, if damaged badly enough cause fuel to get into the oil tank, but it is pretty rare. The VRO has a bad "rap" with alot of boaters due to inexperienced or unschooled "mechanics" who can't find a reason for a powerhead failure and point their finger at the pump. I've owned VRO equipped Johnson's since 1991 - although I've since sold them, I know the owners and they're still running fine. I only know of 2 bonified VRO failures we serviced at our dealership in the last 5 years. In my opinion, that's pretty reliable. If you ever hear someone say "My V-6 engine blew 2 cylinders, the mechanic said the VRO failed..." Thats a physical impossibility - the pump mixes fuel and oil and sends that mix to all the carbs. It cannot selectively oil (or not oil) 1 or more cylinders - whoever says that should find a new mechanic.<br /><br />Disconnecting it will not harm the system. The wires only purpose is to monitor the oil flow, it will have no effect on the fuel pump portion of the unit. If I disconnected it, I would be reluctant to put it back in service 1 or 2 years later. If you want to keep the oil injection feature, I would suggest a new pump (Bombardier recently made some "intelligent" changes to the OMC designed pump and it should really enhance reliability - but, they are pricey). If the fuel pump portion were to eventually fail, you could convert to a fuel only pump to save money. And lastly, that 45 cubic inch motor is loop charged (a looper).<br /><br />-John