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  1. #1

    Question "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    My buddy and I am at "Wits End" on this 115 Johnson.
    The boat has sit inside for 4-5 years-before that the alarm had been going off indicating oil/VRO pump problem.

    Fast foward=New VRO, all 4 carbs rebuilt, new tank pick up pipe, 2 new fuel pump up bulbs, in-line fuel filter.

    Last repairs, we went into the new VRO assembly==Had a tan, Coffee with creme color, with some light grit on the air motor side of the VRO. The fuel and oil side of the VRO pump seemed clean with fuel/oil.

    Had it out today, and it would idle a lot better, and would run fine up to around 2700RPM, and then just lay down flat. The Stratos boat would not come up on plane unless the choke/primer switch was held in.

    On the last VRO repairs, the vacuum pulse valve also had that same tan "Mud/Grit" in it??

    Does it sound likely that a headgasket O ring could be leaking into the crankcase and pushing pressure instead of vacuum on the pulse valve/spark arrestor???

    Our next step is to pull down the VRO=AGAIN= to see if that same "Mud" looking stuff is in the vacuum source to the VRO???

    We would thank you all for help...Bill.

  2. #2
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    The VRO is driven by pressure pulses and not so much vacuum.-------The pulse limiter is a " flow fuse " to protect the VRO.------And no it is impossible for a cylinder head o-ring to leak into the crankcase.--You need to review how this motor is built.-------Sounds like maybe there was water inside this motor.-----I think the motor needs to come apart for inspection.----Sounds EXPENSIVE , but that is my opinion.

  3. #3

    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Quote Originally Posted by racerone View Post
    The VRO is driven by pressure pulses and not so much vacuum.-------The pulse limiter is a " flow fuse " to protect the VRO.------And no it is impossible for a cylinder head o-ring to leak into the crankcase.--You need to review how this motor is built.-------Sounds like maybe there was water inside this motor.-----I think the motor needs to come apart for inspection.----Sounds EXPENSIVE , but that is my opinion.
    Please tell me "how this motor is built"..How does it get "water inside this motor", please, and where/how could it get into the pulse limiter and on the air motor side of the VRO?
    Thanks much..Bill.

  4. #4
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    What is your compression? Did you prime the VRO correctly? It can get water inside the motor by being submerged, to name a few. Water can get into the pulse port just by being in the crankcase. And if your boat won't come up on plane without the primer pressed in, that is a carb issue.
    Last edited by flyingscott; 12-06-2019 at 01:24 AM.

  5. #5
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Was replacement VRO/OMS an OEM or cheap knock off??? Was vapor separator cleaned? These block due to the way they are made can leak at the glue seams allowing water to enter block but more profound on the V-6 models.
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  6. #6
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Did you actually confirm it was water in the pulse limiter and not gasoline?
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  7. #7

    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Quote Originally Posted by flyingscott View Post
    What is your compression? Did you prime the VRO correctly? It can get water inside the motor by being submerged, to name a few. Water can get into the pulse port just by being in the crankcase. And if your boat won't come up on plane without the primer pressed in, that is a carb issue.
    I have not checked compression, that is the next step. I did not prime the vro, but the oil side+fuel side chambers seemed clean and the oil is working. What is the most likely source of water getting into the crankcase? The carbs were overhauled by another person??

    Quote Originally Posted by faztbullet View Post
    Was replacement VRO/OMS an OEM or cheap knock off??? Was vapor separator cleaned? These block due to the way they are made can leak at the glue seams allowing water to enter block but more profound on the V-6 models.
    The VRO is a OEM Johnson part. I replaced the vapor pump diaphragm, the inside of the vapor separator "bowl" was very clean.

    Quote Originally Posted by Docksidemarineservices View Post
    Did you actually confirm it was water in the pulse limiter and not gasoline?
    To me, the material in the pulse limiter looked like "Lake water Mud"??

    Thanks for all the replies..Bill.

  8. #8
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Water / mud inside an outboard crankcase spells near instant death for the bearings.-------I say take this motor apart for inspection.-----Likely it was submerged / near submerged and water got in via the exhaust ports.-------When exhaust ports ( piston at bottom of stroke ) are open the intake ports are open as well.----A clear path to the crankcase !

  9. #9

    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Quote Originally Posted by racerone View Post
    Water / mud inside an outboard crankcase spells near instant death for the bearings.-------I say take this motor apart for inspection.-----Likely it was submerged / near submerged and water got in via the exhaust ports.-------When exhaust ports ( piston at bottom of stroke ) are open the intake ports are open as well.----A clear path to the crankcase !
    Thanks for the info, race...Here's the thing=This is my buddies boat, bought new, has kept up with the maintenance/and service with it since new.
    It has not been submerged or had water over the cowl. It HAS sat for 3-4 years while my buddy was going through shoulder problems. The boat has always been stored inside of His unheated garage. The boat/motor was bought by my Buddy New in 1995, so He knows the full history of it.
    I am NOT a boat tech, but I am a retired GM Master auto tech, and have been told that I have some mechanical ability. I just can not wrap my head around how this "Pulse System" works into the VRO??
    I am use to car vacuum systems (or turbo boost systems)
    Another "Problem" here is that another boat mechanic first of all replaced the VRO pump (OEM) and went through all 4 carbs.??
    I do NOT know if this "Mechanic" is part of the cause of this problem??

    Thanks again for all of the support/info here on the forum..Bill.

    PS: My Buddy did check the compression today=He said 149 PSI on all 4 cyls..

    PPS: And, yes, we are in the process of getting a OEM Service Manual for this engine for a better understanding/description of operation of this 115...
    Last edited by Billybob44; 12-06-2019 at 05:54 PM.

  10. #10
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Crankcase pressure pulses move a piston inside the VRO.----This in turn pumps the fuel and mixes the oil into the fuel.-------The " pulse limiter " is merely a safety device to protect the VRO from a sudden pressure spike.------That would cause the VRO air motor to break.

  11. #11
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    There is no (pulse system) in the motor. The VRO is an air motor that is driven by the cranckase pulse resulting from the normal operation of the motor. The pulse limiter (should be blue) prevents a lean sneeze/backfire from reaching the VRO pump. There is a specific procedure for priming a VRO pump. And the fact you have to hold the primer in to make it run better points to the CARBS!!!! The primer bypasses the carbs and puts fuel directly into the crankcase.

  12. #12
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    VRO/OMS pump work off both pressure and vacuum crankcase pulses.
    There is a pair of check valves that route the +/- pulses to either side of air motor piston. I'll bet a mud dauber built a nest in air intake and that has been sucked into crankcase(bad). This is where your mud and grit came from in old VRO and limiter..
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  13. #13

    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Quote Originally Posted by faztbullet View Post
    VRO/OMS pump work off both pressure and vacuum crankcase pulses.
    There is a pair of check valves that route the +/- pulses to either side of air motor piston. I'll bet a mud dauber built a nest in air intake and that has been sucked into crankcase(bad). This is where your mud and grit came from in old VRO and limiter..
    Thanks for that suggestion, that may very well may have been what happened. We will closely inspect the air intake box for any more.
    We will pull down and check the hose on the pulse limiter again, and if there is no more of the "Mud" content, we are going into the carbs next to inspect float levels.
    Since we do not have the OEM Service Manual yet, can someone give me the specs on the float level in the carbs, and the vapor reservoir ??

  14. #14
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    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Maybe you should try cleaning the carbs and buying good quality gasket kits for them. Or maybe take it to a dealer and let them sort it out.
    Last edited by flyingscott; 12-07-2019 at 01:25 AM.

  15. #15

    Default Re: "95" Johnson 115 Fast Strike-Bogg down+heavy surge 2700 RPM and up..

    Quote Originally Posted by flyingscott View Post
    Maybe you should try cleaning the carbs and buying good quality gasket kits for them. Or maybe take it to a dealer and let them sort it out.
    Thanks Scott on the carb suggestion+I think that is our next direction..

    Ha.Ha...We (My Buddy and I )are retired GM Dealer Employees, so we KNOW what they charge???...Bill.

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