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  1. #1
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    XP 150 Fuel Pump - Vacuum switch question

    I have an 89 Evinrude XP 150 TE150SLCEM that has had the VRO system removed and a regular fuel pump installed (EMP 1399-07359). My question is since the VRO system has been removed and the fuel pump is ran off of the larger vacuum port on the bottom of the engine, can I bypass the vacuum switch (pictured)? All of the fuel lines have been replaced but they are kinking really bad in multiple spots - I could avoid the kinking of one hose if I could bypass the vacuum switch...

    I just didn't know if the vacuum switch is actually doing anything since the VRO system has been completely removed.

    Thanks for any help.
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    Last edited by taterjones; 07-26-2018 at 08:37 AM. Reason: Incorrect Year - Added Model #

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    #2
    Fuel lines may be to long causing the kinking and some may need to be rerouted. If the switch is still connected at the original location it will work. It is a warning system for low fuel pressure, which could cause a lean condition and possible motor damage. I would leave it connected.

  3. SC Club Moderator ChampioNman's Avatar
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    #3
    Leave it connected as Juggy says you need it. Correct your hose lengths to correct the kinks.

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    #4
    Quote Originally Posted by taterjones View Post
    I have an 88 Evinrude XP 150 that has had the VRO system removed and a regular fuel pump installed (EMP 1399-07359). My question is since the VRO system has been removed and the fuel pump is ran off of the larger vacuum port on the bottom of the engine, can I bypass the vacuum switch (pictured)? All of the fuel lines have been replaced but they are kinking really bad in multiple spots - I could avoid the kinking of one hose if I could bypass the vacuum switch...

    I just didn't know if the vacuum switch is actually doing anything since the VRO system has been completely removed.

    Thanks for any help.
    I do not think the alarm is still installed on the boat. Obviously I mix the fuel @ 50:1 in the tank since the VRO system has been removed.

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    #5
    I do not believe that the warning system/buzzer is still installed on the boat. Obviously I premix @ 50:1 since the VRO system was removed previously. Oh the joys of trying to figure out an old boat after previous owners...

    So if the warning system is not installed then the vacuum switch isn't going to do me any good either way...?

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    #6
    If the alarm is not connected, you will also have no warning if the motor overheats and will be then alerted by that final "squeak" and "thunk" as the engine locks up.
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  7. "OVER THE LINE SMOKEY!" headhigh's Avatar
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    #7
    I'm in the same predicament. Previous owner had electric fuel pump installed. I've since gone back to the pulse pumps, but now I'm in the process of reinstalling the vapor separator (fuel bracket) and hooking up the vacuum switch and alarm system.
    1998 Ranger R93
    1998 Mercury 200 EFI

    "Life, liberty, and the pursuit of happiness."

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    #8
    Quote Originally Posted by headhigh View Post
    I'm in the same predicament. Previous owner had electric fuel pump installed. I've since gone back to the pulse pumps, but now I'm in the process of reinstalling the vapor separator (fuel bracket) and hooking up the vacuum switch and alarm system.
    My thinking is (and it may not be right...) that since I am not depending on the VRO to mix oil/fuel together because of the replacement fuel pump (which I think is probably better anyway) why would I need the vacuum switch if the motor is getting oil from the premix, except for the alarms, which I don't think work anyway...

    That's why I asked on here - folks a lot more knowledgeable than me...

  9. SC Club Moderator ChampioNman's Avatar
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    #9
    Quote Originally Posted by taterjones View Post
    I do not believe that the warning system/buzzer is still installed on the boat. Obviously I premix @ 50:1 since the VRO system was removed previously. Oh the joys of trying to figure out an old boat after previous owners...

    So if the warning system is not installed then the vacuum switch isn't going to do me any good either way...?
    A quick check would be to disconnect the temp sensors (tan wires) from the cylinder heads, turn the key to on and touch the motor side tan wires to a clean engine ground with the key in the on position. You should hear the chirp.

  10. "OVER THE LINE SMOKEY!" headhigh's Avatar
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    #10
    Quote Originally Posted by taterjones View Post
    My thinking is (and it may not be right...) that since I am not depending on the VRO to mix oil/fuel together because of the replacement fuel pump (which I think is probably better anyway) why would I need the vacuum switch if the motor is getting oil from the premix, except for the alarms, which I don't think work anyway...

    That's why I asked on here - folks a lot more knowledgeable than me...
    Yes, there are YEARS and YEARS of knowledge here. You came to the right place for help.

    Also, I get the chirp when I turn my key on, so I believe my over temp alarm is still hooked up.
    1998 Ranger R93
    1998 Mercury 200 EFI

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    #11
    Should the pulse limiter still be installed since the VRO system has been removed? Sorry for so many questions - looking at diagrams and then at the motor gets confusing...

    Thanks

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    #12
    Quote Originally Posted by taterjones View Post
    My thinking is (and it may not be right...) that since I am not depending on the VRO to mix oil/fuel together because of the replacement fuel pump (which I think is probably better anyway) why would I need the vacuum switch if the motor is getting oil from the premix, except for the alarms, which I don't think work anyway...

    That's why I asked on here - folks a lot more knowledgeable than me...
    I think your questions have been answered on why you need the warning systems. On some motors the pulse limiter was replaced by just a hose fitting, when the VRO was replaced. None of the things you have asked about were installed on your motor because it wasn't needed. If you have the regular control box the horn is in the box. If you have the built in control box the horn will be under the console probably wire tied to one of the steering cables.

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    #13
    Quote Originally Posted by headhigh View Post
    I'm in the same predicament. Previous owner had electric fuel pump installed. I've since gone back to the pulse pumps, but now I'm in the process of reinstalling the vapor separator (fuel bracket) and hooking up the vacuum switch and alarm system.
    Hey, where have you been hiding out? I need you to keep me inline, I almost had something good to say about CDI the other day, but I was afraid you would see it.

  14. SC Club Moderator ChampioNman's Avatar
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    #14
    Quote Originally Posted by taterjones View Post
    Should the pulse limiter still be installed since the VRO system has been removed? Sorry for so many questions - looking at diagrams and then at the motor gets confusing...

    Thanks
    You're still going to need the pulse limiter to drive the vacuum side of the fuel pumps.

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    #15
    Quote Originally Posted by ChampioNman View Post
    You're still going to need the pulse limiter to drive the vacuum side of the fuel pumps.
    Thank you!

  16. "OVER THE LINE SMOKEY!" headhigh's Avatar
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    #16
    Quote Originally Posted by 316jughead View Post
    Hey, where have you been hiding out? I need you to keep me inline, I almost had something good to say about CDI the other day, but I was afraid you would see it.
    Don't use the "C" word on here Jerry!! You know the rules!

    You guys have my old Fast Strike running so darn good that I spend all my days out on the water. I haven't had much time (or need) to be on here asking questions.

    With that being said, I've realized that my carbs leak a lot more than they should, even shortly after being rebuilt with new bowls and gaskets. I really have no explanation for it other than the fact that my premixed fuel runs straight from the fuel pump to the manifolds and carbs. (No vapor pump installed). I've developed this "high fuel pressure" theory due to the lack of the vapor pump being installed, so I'm in the process of reinstalling it. I've ordered new O-rings and gaskets, so when those show up I'm going to throw it all together and see if it helps. Like I said, it's just a theory, and the floats and needle valves should control the fuel pressure in the carbs. But it won't hurt to try it. I'll let you know how it goes in another thread. Don't want to hijack this one.
    1998 Ranger R93
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  17. Ohio Fishing Reports Moderator omcforever's Avatar
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    The Devil...CDI.

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  18. SC Club Moderator ChampioNman's Avatar
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    #18
    Quote Originally Posted by headhigh View Post
    Don't use the "C" word on here Jerry!! You know the rules!

    You guys have my old Fast Strike running so darn good that I spend all my days out on the water. I haven't had much time (or need) to be on here asking questions.

    With that being said, I've realized that my carbs leak a lot more than they should, even shortly after being rebuilt with new bowls and gaskets. I really have no explanation for it other than the fact that my premixed fuel runs straight from the fuel pump to the manifolds and carbs. (No vapor pump installed). I've developed this "high fuel pressure" theory due to the lack of the vapor pump being installed, so I'm in the process of reinstalling it. I've ordered new O-rings and gaskets, so when those show up I'm going to throw it all together and see if it helps. Like I said, it's just a theory, and the floats and needle valves should control the fuel pressure in the carbs. But it won't hurt to try it. I'll let you know how it goes in another thread. Don't want to hijack this one.
    did your "High Pressure" delivery system involve an electric fuel pump?

  19. "OVER THE LINE SMOKEY!" headhigh's Avatar
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    #19
    Quote Originally Posted by ChampioNman View Post
    did your "High Pressure" delivery system involve an electric fuel pump?
    It did when I bought it Fred. I changed it back to the stacked pulse pumps over a year ago, but didn't put the fuel bracket/vapor separator back on it when I did.
    1998 Ranger R93
    1998 Mercury 200 EFI

    "Life, liberty, and the pursuit of happiness."

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    #20
    Pictures you requested ChampioNman

    Let me know what you think.
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