TN27 5 hp leaking carburetor

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236671

    Fuel coming out of small hole – see pic

    80FC4AF4-2726-46B5-8B28-F3948D85F2A4

    Is this a float valve seat problem. I cleaned the float pin and the float rises and shuts of the fuel. But i have a continuous drip from that small hole

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    reivertom

    US Member - 2 Years
    Replies: 707
    Topics: 37
    #236677

    This site has a bunch about these motors and the earlier models. Here’s the part about the carbs. http://pochefamily.org/outboard/CarbService.html

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236687

    Thanks Tom

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    aquasonic

    US Member - 2 Years
    Replies: 485
    Topics: 36
    #236690

    Michael, I’m having trouble telling exactly where the fuel leak is. Could you describe it in a little more detail?

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236693

    Yes I will try. If you look at the picture towards the top you will notice a black dot that appears shiny. That is some type of vent hole. when I open the fuel valve and and give the starter rope a pull, the fuel starts dripping out of this hole. I can only stop the flow by shutting off the valve at the tank. I hope that helps. The motor runs fine at a slow speed. I have not taken it to the lake to try high speed tests. I have to get this fuel leak solved first.

    frankr
    frankr

    US Member - 1 Year
    Replies: 5666
    Topics: 49
    #236707

    Not 100% sure, but I think your float valve is leaking a tiny bit. Can we assume the cork float is ok? I long ago quit trying to seal them with dope. To each his own, I guess. I use a Mercury nitrophyl float. But if that is not the problem, and you cleaned the float pin and seat and it still drips, you might have to take more drastic action. I agree with the link, and do not believe in the valve grinding method, although I have done it with success (sometimes). My do-or-die method is to “coin” the seat. With the carb assembled, remove the plug directly below the float pin and push the float pin against it’s seat with a punch. Now, tap the punch LIGHTLY with a small hammer. I gotta tell you though, this is an art. If it still leaks try again, a bit harder. Of course, there is a point of destruction,, so proceed at your own risk. I used to work in a plant that manufactured hydraulic valves and we coined 1000’s of seats most every day.

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236709

    Thank you Frank, That screw is the one that I could not get loose. I will try it again and break it loose. After that I will inspect it and clean it out. I will try coining it with the right size drift and a small ball peen. That makes sense to me and it should seat it. As always I do appreciate the tips. I will be careful. I do not want to mess up this motor after I got it all fixed, painted and new decals on her.

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    lloyd

    US Member - 2 Years
    Replies: 283
    Topics: 2
    #236713

    I am also having trouble seeing where it is leaking from. I don’t see a “black dot that appears shiny” and I don’t recall any “vent hole” in that area. But assuming your cork is OK it is very likely that the float valve is dirty causing the float chamber to overflow from the top and run down the side of the float chamber and drip from the bottom of the carb. It is routine to clean out the float valve because dirt and old varnish will accumulate in that area causing the tapered bottom of the float needle not to seat properly, but it is rarely if ever necessary to tap the taper against the seat with a hammer and I don’t recommend it. You can spin the taper with a small diameter pencil eraser to assure it seats well. If you like you can call me and I will explain how to do it. 231-929-7479.

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    crosbyman

    Canada Member - 2 Years
    Replies: 2054
    Topics: 225
    #236715

    see pic

    Joining AOMCI has priviledges 🙂

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    lloyd

    US Member - 2 Years
    Replies: 283
    Topics: 2
    #236719

    The photo that Crosbyman posted above shows a float pin that appears to be made of steel. Every float pin I have ever seen was made of brass and they don’t “corrode”. They just get dirt and varnish on them. In any case, if you clean out the valve chamber and spin the float pin as I described above and that solves the problem, no more is needed. If it doesn’t solve the problem then the float pin can be removed and cleaned or the float may need to be replaced.

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236720

    Lloyd,
    I took the carb apart and removed the float and float pin. It was dirty and when gently pushed into the seat it would stick. I cleaned and polished the pin, cleaned and redoped the float and put it back together. The float pin movement was much better. After all was assembled i gassed her up and no leaks. Sea trials on a cold lake scheduyfor tomorrow.

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    56C1EE60-6F79-4286-8546-9F9CF65B69E6

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236725

    Mine is brass and i polished like a mirror, problem solved

    Thank you for your help. Your seals worked in the primer too.

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    Michael Purpura

    US Member - 2 Years
    Replies: 45
    Topics: 12
    #236726

    Frank,
    I cleaned and polished the brass float pin. Now it seats snd stops the fuel flow. Thank you for your help with this problem
    Mike

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    lloyd

    US Member - 2 Years
    Replies: 283
    Topics: 2
    #236728

    Glad to hear it Michael and you did exactly the right thing!! And your motor looks beautiful from what I can see. Good luck and have fun on the lake tomorrow!!

    frankr
    frankr

    US Member - 1 Year
    Replies: 5666
    Topics: 49
    #236737

    Glad you got it fixed. Anyhoo,, here’s the hole nobody can seem to see.

    the-hole

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