Fuel problem

Hi all. I am new to this forum and I require some assistance diagnosing a problem with my 1987 Johnson 150 V6 outboard. I have had a problem that seems to be fuel starvation. My VRO system has been disabled and I am running a pre-mix. I have installed new hoses, primer bulb and fuel filter. The fuel tank has been cleaned and re-installed with a new pick up tube. I have re-built the carbs. Starts ok and then seems to die out unless I pump the primer bulb. Definitely no air getting into the fuel system as I have fitted all new hoses and stainless clamps. I suspect the problem is the fuel pump and I will have to order a replacement twin fuel pump on Ebay or Amazon as I am in South Africa and it it not simple to obtain spares.

Thank you in advance for any valuable assistance.

Take the VRO pump apart for inspection.----Might be an easy fix.-----What does a compression test show on this motor ?

I'd forget about the VRO and stay on Pre-Mix.

I have removed all parts associated with the VRO system, including the oil tank. I have stripped the VRO and the diaphragm seems to be in good condition. I will do a compression test on all the cylinders later this morning.

Morning all. I have done the compression test and have cylinder 1 at 88 psi, cylinders 2, 3, 4 and 5 at 80 psi and cylinder 6 at 75 psi. I have also installed a new remote control and am now finding that the motor does not switch off when I turn the key off. It only cuts off when running out of fuel. The previous owner has cut the black and yellow wire on the port side coming from the connector and I have re-connected it. Very frustrating. Appreciate any help that can be given.

I have sorted out the switching off issue. I was able to determine that only one bank of cylinders was not switching off and then by removing the plug leads, found that the starboard side was not switching off. Cut out the black rubber connector on the black/yellow wire and re-connected the wire and all perfect now. Just my fuel issue I need to sort out now.

For your compression, run some OMC ENGINE TUNER through the motor following the directions on the can.

I don't know much about the VRO on this particular engine, but could the OP simply order a standard fuel pump like the one in the link below? This particular pump is for a 1983 150HP which would be the last year before VRO was introduced.

http://www.marineengine.com/newparts/part_details.php?pnum=OMC0438559

KJ

Hi KJ. Thanks for the input. I have ordered a new fuel pump, but I believe my 150 V6 takes a dual fuel pump, which is the one I have ordered.

Compression values are a concern.-----Perhaps test with another gauge.------The 83 model 150 HP crossflow used 2 simple and sperate fuel pumps.

I have done a simple test for the fuel supply. I removed the fuel hose and have run the petrol (or gas as you call it) from a small tank via gravity from a height above the motor. The motor ran fine and did not cut out. This tells me that it must be the fuel pump that is faulty. My new dual fuel pump should be here on Friday.