Low Cyl Pressure - Quick Q

Discussion in 'Bubba's Outboards' started by cpalombo, Aug 6, 2009.

  1. cpalombo

    cpalombo New Member

    Messages:
    318
    State:
    Nashville TN
    I have a 2001, two-stroke, auto oil mix, 50 HP tiller Merc with 135 pressure in the top and bottom cyl and 25 in the center cyl. From what I am told, it just "started running funny one day" (in other words, I don't know what led to the center cyl getting fried). I know that I will need to replace the center cyl with an oversized one and get it rebored, however, I have another question....

    What is the list of things to check to figure out what caused the problem in the first place? Since it is an automatic oil mix, I assume that the elec oil pump needs to be checked for function. Is there other items I should test to make certain the cyl does not get re-fried after I rebuild it????

    Also, what should labor cost me for such a repair? I plan on posting a Craiglist add in St Louis to see if I can find a handy person with the proper tools.

    Thanks!

    ~CP
     
  2. catin38

    catin38 New Member

    Messages:
    272
    State:
    alabama
    are you sure its in cylinder. have you checked head gasket?
     

  3. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Most times the center cylinder goes its the carb on that cylinder As it was not getting enough gas thus not enough oil also.
    But as the other post also check gasket it may well be the only thing that is wrong. Most times when a cylinder goes down enough like that. Your going to hear something. Not just it acted funny.
    Pete
     
  4. Rollinunknown

    Rollinunknown New Member Supporting Member

    Messages:
    2,286
    State:
    Missouri
    Sounds like a head gasket to me also.If theres no knock or bearing damage then your fine .. might even be a bad ring pull the head and check it out its nothing hard to do .Get a manual and get to work.It will save you from 500-1800.

    Again if its the gasket its nothing major take your time and get the spec sheet for the motor witch tell's you how much the bolts need to be torqd down.


    people say you gotta runem 50.1 but i run all my 2 stokes @ 38.1 if im not racing them.

    I ran 2 stokes atv's for my whole life.They are by far the easyist thing to work on.

    And aslo ditch the dang auto mixer .... do it your self so you know its getting the right Air/fuel.
     
    Last edited: Aug 6, 2009
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Pull the head plate and check to see if any damage is done to the wall or piston before you start taking it to the repairman. could have blown a gasket.
     
  6. cpalombo

    cpalombo New Member

    Messages:
    318
    State:
    Nashville TN
    Awesome. I am going to buy an engine manual right now and start working on it. I am also going to buy the tools that I need to check the gasket. It would be just awesome if that engine just needed a new gasket. It only has 60 hours on it, and it would be really nice if I could fit it myself (I need to get better at fixing my own small engines anyway!).

    Quick question... could I just buy any compression tester from autozone, or do I need a specific one for outboard motors??? any ideas?

    Thanks,

    CP
     
  7. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Anyone with a 14mm screw in type hose
     
  8. catin38

    catin38 New Member

    Messages:
    272
    State:
    alabama
    you can go to any parts house and just get a regular ole tester. most have different screw in adapters to fit almost anything. i bought a craftsman and it will fit almost anything
     
  9. cpalombo

    cpalombo New Member

    Messages:
    318
    State:
    Nashville TN
    Hey all. I appreciate all the info. However, I got the motor to my place in O Fallon MO... and after looking over the repair manual, the process of fixing this scared me so bad that I am going to hire someone to fix it for me. And "yes", I am okay with laying aside my self respect and declaring defeat before I even try. :) There just looked like a lot of parts for me to loose, put on backwards, put in the wrong place, break, or drop into the other cylinders. I can tear down and put together a pharmacy program... but outboard motors are beyond me.

    Anyhow, what would a 1-cylinder repare job cost me? Any ideas? Does anyone know a good name in the St Louis area who is honest and can get it right the 1st time?

    Thanks!

    ~CP
     
  10. BKS72

    BKS72 New Member

    Messages:
    3,361
    State:
    East of KC
    Hard to say. Even for a 1 cylinder repair they have to pull the powerhead and split the crankcase to get at the bad piston/ring. If it needs to be bored over they'll have to pull the rotating assembly (crank and all rods/pistons) and have the cylinder bored.

    Parts cost will be relatively minor if they can re-use all your bearings and just have to replace a piston and rings and whatever gaskets have been disturbed.

    If I had to just shank a number out there I'd guess around $700 give or take a couple hundred either way depending on what they find when they get into it. Most of that will be labor if the shop you use is like most of them around here and charging $70 to $90 an hour.

    If you're lucky and it's just a stuck ring and no cylinder damage you could get off quite a bit cheaper.
     
  11. cpalombo

    cpalombo New Member

    Messages:
    318
    State:
    Nashville TN
    Thanks dude. Here is the funny thing. That motor has an elec hour meter in it. I only has 60 hours, and looks BRAND NEW inside and out. The story goes that a farmer used it for 4 trips to Canada before the cylinder went. It still ran but ran hard. Anyhow, he set it back in the shipping pallet until he could fix it himself... which he never did. So, it is basically a new 10 year old motor.

    Totally nuts.

    Thanks for the invite. $700 for a total job, less if it is a stuck ring and things are in good shape.

    ~CP
     
  12. BKS72

    BKS72 New Member

    Messages:
    3,361
    State:
    East of KC
    That's a guess, but I'd bet it's pretty close. Out of curiosity did you pull the head and check the gasket and cylinder wall condition? If it's just a gasket you could get out of it for a lot less than my $700 guess.