Carb tuning question?
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Carb tuning question?

  1. #1
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    Default Carb tuning question?

    Posted this in the V-drive forum as well, lots of jet boats with wet stacks, so hopefully my issue has already been resolved by someone:

    Has anybody successfully done a temporary installation of a wide band O2 sensor and AFR gauge to dial in a carb? I'm able to set up the sensors no sweat, my concern is how to keep it dry since I have wet stacks. My thought is to setup a temporary inline tube where the rubber hose interconnects the riser outlet to the transom trumpet. I can redirect the water overboard briefly, I'm just not sure how fast the heat will get out of hand and melt the rubber tubing (real quick I presume).

    Any thoughts or first hand experience with this would be great, I'm installing a new carb on my old DiMarco 21 this week to free up the second carb for my other motor. Planning to tune it this weekend an would refer to be able to dial it in using the AFR.

    Thanks

    Mike

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  3. #2
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    Quote Originally Posted by 5bravobravo View Post
    Posted this in the V-drive forum as well, lots of jet boats with wet stacks, so hopefully my issue has already been resolved by someone:

    Has anybody successfully done a temporary installation of a wide band O2 sensor and AFR gauge to dial in a carb? I'm able to set up the sensors no sweat, my concern is how to keep it dry since I have wet stacks. My thought is to setup a temporary inline tube where the rubber hose interconnects the riser outlet to the transom trumpet. I can redirect the water overboard briefly, I'm just not sure how fast the heat will get out of hand and melt the rubber tubing (real quick I presume).

    Any thoughts or first hand experience with this would be great, I'm installing a new carb on my old DiMarco 21 this week to free up the second carb for my other motor. Planning to tune it this weekend an would refer to be able to dial it in using the AFR.

    Thanks

    Mike
    I dont know if this helps you or not. But i have a friend that had forgot to turn his water on (idiot i know) He melted his exhaust tubing very quickly...

    I have a wideband on my boat, If/When i inject the water the readings get very screwy.

    I know that Mercruiser has o2 adapter plates that go between the logs and the riser. I dont know if something like that is an option for you?

    Oxygen Sensor Spacer | Wags Engineering

    theres also this one
    Oxygen Sensor Plate Fuel Injection Mercruiser O2 EFI | eBay
    Last edited by steves86ta; 01-27-2016 at 07:48 AM.

  4. #3
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    Quote Originally Posted by steves86ta View Post
    I know that Mercruiser has o2 adapter plates that go between the logs and the riser. I dont know if something like that is an option for you?

    Oxygen Sensor Spacer | Wags Engineering

    theres also this one
    Oxygen Sensor Plate Fuel Injection Mercruiser O2 EFI | eBay

    Thats the solution I landed at. I'm fabricating a spacer to drop int between the log and the snail on my old Hardin Marine wet stacks.

    How are you set up that gives goofy readings with water? My goal is to be able to collect numbers from the the sensor while underway on the lake, set up the carb using the O2 sensor and gauge, and pull the instrument off once I hit a satisfactory tune.

    Thanks for your input. I really appreciate it.

    Mike

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    Quote Originally Posted by 5bravobravo View Post
    Thats the solution I landed at. I'm fabricating a spacer to drop int between the log and the snail on my old Hardin Marine wet stacks.

    How are you set up that gives goofy readings with water? My goal is to be able to collect numbers from the the sensor while underway on the lake, set up the carb using the O2 sensor and gauge, and pull the instrument off once I hit a satisfactory tune.

    Thanks for your input. I really appreciate it.

    Mike
    Hi Mike,
    Im running a LS engine in a 1970 Rogers. I built a set of over transom headers for mine. So my headers are injected via manual valve at the driver seat. I can run them dry if i want to.

    I dont have a picture of the sensor, but its on this bank about 18" from the exit


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    Default One sensor or two?

    Thanks for the response

    Are you running a sensor on each side? Or just one side?

    I'm machining a puck to adapt the sensor upstream from the riser. Trying to decide whether to run one or both sides. Pretty sure I will install a cheap narrow band sensor first before I put my nice wide band unit in there.

  8. #6
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    Quote Originally Posted by 5bravobravo View Post
    Thanks for the response

    Are you running a sensor on each side? Or just one side?

    I'm machining a puck to adapt the sensor upstream from the riser. Trying to decide whether to run one or both sides. Pretty sure I will install a cheap narrow band sensor first before I put my nice wide band unit in there.
    Im only running one

  9. #7
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    Quote Originally Posted by 5bravobravo View Post
    Pretty sure I will install a cheap narrow band sensor first before I put my nice wide band unit in there.
    My experience: Don't bother with the narrow band sensor. I also tried to go cheap and read the voltage output. It works, but the Bosch sensors I used didn't last long at all (1 or 2 outings). Go with an AEM set-up. You'll be time (= $$) ahead at the end. The AEM sensor has been bulletproof for me. Been running it for 3 years now. No problems. BUT: I'm not running it wet either.

  10. #8
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    Good info.

    I have a nice wide band unit on hand. Guess if I roast the sensor I can replace it for less than the cost of the whole unit, probably not that much more than a narrow band sensor.

    I'm anxious to try it out. Not sure how likely it is to get wet yet.

    Haven't got my adapter puck done just yet, probably next week.

  11. #9
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    Quote Originally Posted by mpkardell View Post
    My experience: Don't bother with the narrow band sensor. I also tried to go cheap and read the voltage output. It works, but the Bosch sensors I used didn't last long at all (1 or 2 outings). Go with an AEM set-up. You'll be time (= $$) ahead at the end. The AEM sensor has been bulletproof for me. Been running it for 3 years now. No problems. BUT: I'm not running it wet either.
    I have the AEM i love it. I asked AEM about water injection and they were very against it. Though they did say they havent tested it either

    Jsut an FYI the AEM gauge uses a Bosch sensor 4.9 LSU sensor. I heard this is a better sensor

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