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40hp vro fuel pressure

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dan t/a

New member
i own a 88 40hp johnson vro (disactivated ) it starts well with the manual pump ,accellerate well and 30 secondes after,it falls on slow speed. i cleaned the carbs (ajust floats) vacuum test all hoses, checked fuel pump diaphragms ,fuel filters . i hooked a vacuum gauge to the pulse port of engine and ad +- 4hg,in at cranking. i went for a test run with a fuel pressure gauge hooked to a carb and i had 3.5 psi and when i went full throttle the pressure dropped to 0 and the engine felt in slow speed.is it possible that the springs in the pump are to weak to pump at high rpm or the pressure drop when the float neddle open?
i am looking to install an electric pump that draw 4.5 amp ,is it too much amps for the charging system?
the coils and the powerpack are new.

thank you for your help
 
Those springs are not the cause of the problem.-----------I would simply install a fuel pump from an earlier pre VRO year.---------Cheaper / easier to maintain and ultra reliable.------------Place on the block to install it is already there.-----Block off the pulse port for VRO with a plug.------Order a pump from an 83 , install it and forget about fuel pump problems.-----------------What is compression on this motor ??
 
When you have the older pump and the gasket in your hands and look at the block ( upper cylinder , port side ) ------you will say " this is easy "-----------Remove the plug that is there for access to the pulse port for the older pump.
 
fuel pressure problem solved by replacing the pump with a pre-vro pump 2 psi at idle and 4psi at full throttle. now i have another problem, after 2 to 5 minutes of running,i lose the top cylinder (no spark) let it rest for a couple of minutes and it spark again . i inverted the coils and same top cylinder fail.i replaced the powerpack (new) and cleaned the sensors under the flywheel,new plugs wires. is there a kind of safety device that cut the ignition or a way to bypass the ignition switch ? it run verry good beside that but i cant use the boat because it s always fall on 1 cylinder after 2 minutes.thank you for your precious help Dan
 
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