24
May
The most common failure in a VRO is the air motor diaphragm when it fails the pump doesnt work - period. Take the top of the tank off and try to get all the gas out of the pump.
If the cylinder has a leak the pump pulse signal will not be strong enough to send the proper amount of fuel to the cylinder.
How to test outboard fuel pump. How to Test an Outboard Fuel Pump. Turn off your main electrical cutoff switch that governs motor ignition. Screw a compression gauge hose into the spark plug hole.
Refer to your owners manual for the correct psi your engine needs. Check to make sure you have enough gas in the tank to be picked up by the sump. Fuel pumps on outboard motors work a little bit differently than they do on automobile engines.
The outboard fuel pump has a sensitive diaphragm that receives a suction signal from a piston cylinder so the pump can deliver fuel. If the cylinder has a leak the pump pulse signal will not be strong enough to send the proper amount of fuel to the cylinder. Outboard fuel pumps rarely fail and diagnosing a fuel problem involves checking.
You can check this by pumping the primer bulb until it feels hard. Fuel should travel easily from the tank all the way to the pump. Your outboard fuel filter located just before the fuel pump should be full.
With the engine off and the cowl cover removed remove. How to Test an Outboard Fuel Pump Flip off your principal electrical cutoff change that governs motor ignition. Screw a compression gauge hose into the spark plug gap.
Often other fuel system components are easier to troubleshoot and eliminate. However if you want to get right to the outboard fuel pump we have the steps you need to know. How Do You Test a Bad Outboard Fuel Pump.
Turn off the main electrical cutoff switch. Fit the gauge with an appropriate adapter and attach the line to gauges test port. In case if you dont find any fuel test port you will need a fuel filter adapter.
It will work as a fuel test port. Fuel Pump Functionality Step Six. When you are done attaching the gauge then turn the ignition key to ON direction.
Splice the clear test line and I say TEST LINE because this is for testing purposes only NO BOAT should ever be used with vinyl line outside of TESTING PURPOSES Start the boat up and run it. Look for bubbles in the clear line. When the outboard is running normally the engines fuel pumps create a slight vacuum in the fuel hose.
Atmospheric pressure in the tank through the vent pushes the fuel from the tank to the engine. In this case the check valves are both slightly open and allowing fuel flow at the rate that the engine is using it. Ok i am guessing you know how to take the vst tank apart if you cleaned the filter.
You can try this and you may get lucky. Its worked for me a few times in the past. Take the top of the tank off and try to get all the gas out of the pump.
Make some jumper wires with the small loops on one end of both wires and nothing on the other end. Put the loops on the studs just like the ones from the harness. Use a set of jumper wiresavalible at radio shack.
Red to battery and black to - and it should run. Squeeze the fuel primer bulb while the motor is running. If the motor runs rough when operating a high speeds and if the motor smooths out when you squeeze the bulb replace the fuel filters clean out the fuel lines and repeat the test.
If the results are the same replace the fuel pump. You can test the output of the high pressure pump but you need some stuff. A pressure gauge that reads at least 50 pounds psi full travelyou dont want one that reads more than 100 or its tough to read at the lower numbers.
About 10-15 feet of 14 fuel hose a 14 brass t and some small hose clampsslide the oil tank out of the way and find the line from the pressure regulator to the fuel rail. Squeeze the fuel primer bulb while the motor is running. If the motor runs rough when operating a high speeds and if the motor smooths out when you squeeze the bulb replace the fuel filters clean out the fuel lines and repeat the test.
If the results are the same replace the fuel pump. Video showing service procedure for mercury 4 stroke outboard fuel supply module consisting of high and low pressure fuel pumps float switch and presuure. Evinrude 90 hp two stroke - fuel pump testing - how to.
Motor starts off the priming bulb so if the bulb pumps until it becomes firm then its proberly not the pump unless its flooding with gas. The pump failing will normally show up when engine is under power. The carbs will starve for gas and the simple check is to get someone to pump the primer if the motor picks up then its proberly the.
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 pumps 2 chambers. The most common failure in a VRO is the air motor diaphragm when it fails the pump doesnt work - period. How to check fuel flow on outboard - YouTube Oct 09 2021 Watching this you can check fuel flow all the way from the tank to the views Oct 09 2021 This video will show you how to check the fuel delivery through your outboard motor.
Johnson Evinrude fuel pump service. Fuel pump vacuum test Low vacuum when drawing fuel from the tank does not mean bad pump per se. It could just be easy flowing and not need much vacuum.
At 5 inmercury i am guessing no check valve. Usually takes 15 to 2 inches just to crack those. Best way to test vacuum ability of a pump is to dead head it.
Vacuum gauge direct to pump. Pump the heck out of the primer ball. If the motor will run while the primer ball is continuously pumped then that is a pretty good indication that the lift pumps are failinghave failed.
Pumping the primer ball is doing the job that the lift pumps should be doing.