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Fuel pump addition

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ShayneCastonguay

Contributing Member
Hey guys, I have an 82 50hp Johnson that I've had a fuel pump hooked up to for priming purposes. It is not a flow-through pump and has been causing me issues while running (I have to routinely tap the prime button to keep it running). I realize I could just use a primer bulb, however I'm thinking about adding in a secondary open line, with an in-line check valve to bypass the pump when the motor is running, and use the pump for priming. Would that work?
 
That's way more complicated than necessary. All you need is a fuel line primer bulb, a good fuel pump, and make sure your choke plates and solenoid are working properly for cold starts. If the carbs are clean and all of that is in good shape you shouldn't have any problems.

If your fuel pump isn't keeping up you might install a fuel pump rebuild kit.
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0393103

If a rebuild kit won't fix it you can install a completely new pump
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0438556

If you have an air leak in the engine case that can cause poor fuel delivery because the pump relies on vacuum pulse off the crank. IF that is your problem, using an electric fuel pump is only masking the real problem.

KJ
 
My running issue is that the mechanical pump isn't pulling through the electric one (because it isn't a flow-through type) so it's cut off from resupplying the carbs. I have the electric pump for convenience, but if I put in a check valved bypass line then the mechanical pump can draw from the tank and the electric pump can resupply the carbs for cold start priming, right?
 
The factory pump on that motor works with a + pressure pulse and a slight vacuum pulse.----Not sure how you can improve that simple , reliable system !
 
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