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Fuel pump pressure 2 stroke 50hp

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cuervosportfishing

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I have a 1999 2 stroke 50 hp J

I have a 1999 2 stroke 50 hp Johnson outboard. We've had the fuel pump die a couple times and they cost about $300 to replace. We are game to experiment a little and think we can use an electric pump at the tank instead of replacing another mechanical. What we need to find out is what psi the electric should be set for? We plan to leave the existing pump in place and just push the fuel through it to the carb. Anyone know the general psi or volume of the stock pump?
 
"Hello Brad, I cannot tell you

"Hello Brad, I cannot tell you exact pressure but would like to relay my concern of such a setup my concern would be if something would happen with all the vibration and so on that goes along with the motor running and rough water what were to happen if line would come loose even if you were to shut motor down pump would not stop and an electric pump can move an amazing amount of fuel in a short amount of time. just a thought."
 
"Brett, would echo David, with

"Brett, would echo David, with one other observation - a mechanical fuel pump will increase/decrease the volume pumped based on engine rpm's.

Electric fuel pumps (automotive style) have a feed back to the fuel tank to take care of any "overflow" or "excess".

I'm not sure how you would set up an electric to provide enough fuel at WOT without severely flooding the carb at idle - it's not so much the pressure as the flow rate that you would have to control - you are feeding a carb, not a computer controlled injector.

Could probably be done but could end up costing you more in (engineering) than your 300 dollar pump.....

My 2 cents..."
 
I agree with Graham a pressure

I agree with Graham a pressure regulator is usually the return path for excess fuel and to buy an adjustable fuel press.reg. and I guess you could use a contactor/relay and pick up a signal off the stator or voltage regulator but all could put harmful return voltage into a rather sensative and EXPENSIVE to repair charging/ignition system. Another thought would be is the mechanic replacing the pulse limiter and check valve (not correct term --there is a part that keeps excess pressure from destroying pump)sorry about run on sentence and spelling!!
 
wouldn't float hight contr

wouldn't float hight control fuel flow into the carbs? on carburated automotive engines there is no return line just a regulator
 
The bottom line on this fix is

The bottom line on this fix is to try and find a cheap and easy solution to keep this older motor running. We've been running the motor short range with a person constantly pumping on the primer bulb and there doesn't seem to be any way to over gas the carb that way. Return lines are generally on fuel injected motors from what i've seen although we could easily route another line back to the tank to return any excess. That could be a way to eliminate the need for a regulator. I was also informed of the possibility that there are fuel pump rebuild kits around for some models. We thought about the rpm issue but in cars this is not a factor - you just need to maintain a constant supply of gas that won't allow air to get sucked into the lines when you throttle up. Thanks for the ideas and help. Pura Vida.
 
"Hello again Brett, I have reb

"Hello again Brett, I have rebuilt VRO's this summer my own and a good friends and the parts total were around 40.00 U.S. am not sure about yours because I beleive the pump for 40-50 hp two cyl. is diffrent. Oh yeah my return line theory may differ from marine to automotive my 76 and 87' vintage BMW's use high press pumps and have return lines, may not apply to something aimed towards carburation. I beleive you would find VRO provides very low press. Good Luck!!! Always room for innovation!"
 
"Brett,

The simplest way to

"Brett,

The simplest way to do this is to replace the VRO pump with an ordinary fuel pump and mix the oil manually. That should only cost about $40 and can't fail.

Tony"
 
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