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  1. #1
    Seaman BURNSY23's Avatar
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    Default 6hp 1966 johnson outboard

    when idling low, it sputters, kicks then stops? why? would it be a twisted crankcase, seeing as there are no bearings?? thanks!

  2. #2
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    Default Re: 6hp 1966 johnson outboard

    How does it run otherwise, like wot???

    Could it be just a slow speed mixture adjustment??

  3. #3
    Seaman BURNSY23's Avatar
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    Default Re: 6hp 1966 johnson outboard

    It runs good, not sur that i get 6hp though , feels like about 4hp. Runs steady. Starts first 2 pulls everytime.

  4. #4
    Chief Petty Officer cajuncook1's Avatar
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    Default Re: 6hp 1966 johnson outboard

    Quote Originally Posted by BURNSY23 View Post
    when idling low, it sputters, kicks then stops?

    It runs good, not sur that i get 6hp though , feels like about 4hp.

    It sounds like its running on one cylinder.....easy to check.


    I going to review a couple things, please don't get offended if I review some basic stuff, because I don't know your knowledge base regarding outboard motor.


    1.) Check to see if you have good spark on both cylinders using a spark plug test, not just a spark on the end of the plug. ( Please undo both plugs, so you don't accident start the motor) Should have a good strong spark at 1/4 to 5/16 inch on the spark plugs tester. (ground the tester to the motor). If you have a cylinder that has no spark or very weak then your basically running on one cylinder. Father in-laws Evinrude 6hp motor was running ok and idle a little rough but it was running on one cylinder, no spark on top cylinder and was running about half power. Had to change the coil on the motor and now it runs smooth and he is happy again. These motors are tough and will run on one cylinder but poorer than usual.

    Another way to tell if you are running on one cylinder is to start up the motor(in the water) and let her warm up for a minute or two. Carefully unplug the boot to the top plug, if runs rough but maintains some then the bottom plug/connnected cylinder is firing. If it dies then you know that you have a cylinder that is not firing/spark. Replace the top spark plug boot carefully and let a run for a minute or two, then unplug the bottom plug boot, if it dies then you know that you have the top cylinder plug/wire that is not firing/spark. If runs rough but maintains some then the top cylinder is firing.


    2.) Check your fuel line going from your tank to the motor. Make sure the primer bulb is near the tank and the fuel arrow flow image is pointing to the motor. Make sure your gas line is in good shape. If in doubt, go to Walmart or Academy and buy a new setup. Because if air is leaking into the line from small crack it could affect your fuel delivery.

    3.) Gas/oil mixture 50:1 = equal 6gallons of gas to 16ounces of TWC-3 2 cycle oil. ( don't let others tell you the stuff in for weed-eaters and chainsaws is ok)

    4.)Spark plugs- Champion J4J (torque to 17 to 20 foot pounds with a torque wrench)
    Spark plugs gapped at 0.030 (use a feeler gauge)

    5.) Make sure your vent plug is open plug on your tank open when your running/starting your motor if you have a plastic tank. (You may laugh, but all of us have forgotten to open that vent plug while starting up the motor in the morning for a day of fishing and find a little while later the motor is running like do do, because the air can't entering the tank. The motor's and fuel pump is now trying to suck gas from a tank that has a negative pressure in it.

    Good luck sir,

    cajuncook1
    Being cheap and not getting a manual will cost you hundreds or maybe thousands of dollars

  5. #5
    Seaman BURNSY23's Avatar
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    Default Re: 6hp 1966 johnson outboard

    thanks so much cajun. I checked for spark and it good on both cylinders. Fuel lines good, i always open the tank so air can get in, also i mix 50/1 always with good marine oil. The kind of spark plug that you said to use is not what is in it, i replaced them with new ones last week after i bought this motor but the are not champion they are the other brand from japan. Could this be the issue?? I figured the previouse owner had the proper ones in it so that is what i replaced them with. Also what if the crankseal is awful?

  6. #6
    Chief Petty Officer cajuncook1's Avatar
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    Default Re: 6hp 1966 johnson outboard

    Quote Originally Posted by BURNSY23 View Post
    thanks so much cajun. I checked for spark and it good on both cylinders. Fuel lines good, i always open the tank so air can get in, also i mix 50/1 always with good marine oil. The kind of spark plug that you said to use is not what is in it, i replaced them with new ones last week after i bought this motor but the are not champion they are the other brand from japan. Could this be the issue?? I figured the previouse owner had the proper ones in it so that is what i replaced them with. Also what if the crankseal is awful?
    The manufacture recommended plugs are Champion J4J.

    Well you did the basic checks for the obvious issues. You stated,

    Originally Posted by BURNSY23 View Post
    when idling low, it sputters, kicks then stops?

    It runs good, not sur that i get 6hp though , feels like about 4hp.
    Now I have to ask, is this a used but new motor to you and just running it now or have you had this motor and this is something new?

    You stated that it has a good spark on both cylinders, so that leads us to fuel delivery. Your carburetor probably needs a cleaning. Junk might have built up or a sticking/stuck float preventing low idling and cutting out. It running poorer than usual at WOT (wide open throttle) may indicated high speed jets are in need of cleaning, so a carburetor cleaning with a new kit is probably in order.

    Here are some links supplied by a couple of people on this forum that have given detail instruction and demonstration on how to do that.

    http://forums.iboats.com/engine-frequently-asked-questions-faq/carb-cleaning-instructions-244013.html (clean your carburetor)

    http://forums.iboats.com/engine-frequently-asked-questions-faq/carb-needle-adjustments-asorted-carb-variations-joe-reeves-167352.html (adjusting your carburetor)

    http://www.sschapterpsa.com/ramblings/OMC_6hp.htm (This is an excellent article about your motor, compliment of the machinist.)

    You should invest in service manual for your motor, if you want to properly maintain it and repair it. $20 to $30 bucks you spend is nothing compared to its benefits.

    http://cgi.ebay.com/ebaymotors/1966-...sQ5fLiterature

    http://cgi.ebay.com/ebaymotors/1967-...sQ5fLiterature

    Carburetor Kit (the iboats kit is cheaper but it does not have replacement float.)

    If you need one you can call Iboats and give them the carburetor kit number supplied below and they can help you out. You can certain order the kit from BPR.

    You can tell if your float is good if you put it in a cup of fuel and it floats. Be sure to remove the float if your are going to soak your carburetor or spray carb clean in the ports and holes, because the carb cleaner will eat up/dissolve plastic parts or the coating around the float.

    http://www.iboats.com/mall/partfinde...****=535538001

    0383052 CARBURETOR REPAIR KIT

    Good luck, please keep us posted!! There are bunch of experience guys on this forum. Hopefully they will chime in if they have a different opinion or other thoughts and support.


    cajuncook1
    Being cheap and not getting a manual will cost you hundreds or maybe thousands of dollars

  7. #7
    Seaman BURNSY23's Avatar
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    Default Re: 6hp 1966 johnson outboard

    thanks cajun,

    Well this motor is new to me, i have had it out fishing twice and found it does the same thing both times. Also when i bought it last month, the guy i got it from said he thought it might need new points, but it turned out that there fine. This motor sat for ten years in a boathouse, in dry conditions he told me. As far as he could remember it always did that sputtering and missing and jerking then cut out thing on low idle. Is the crankcase in these old motors '60-'66? poured brass with no bearings? dont they tend to get out of shape in someway, which cant be fixed?

  8. #8
    Chief Petty Officer cajuncook1's Avatar
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    Default Re: 6hp 1966 johnson outboard

    Quote Originally Posted by BURNSY23 View Post
    thanks cajun,

    Well this motor is new to me, i have had it out fishing twice and found it does the same thing both times. This motor sat for ten years in a boathouse, in dry conditions he told me. As far as he could remember it always did that sputtering and missing and jerking then cut out thing on low idle. Is the crankcase in these old motors '60-'66? poured brass with no bearings? dont they tend to get out of shape in someway, which cant be fixed?
    Well, it seems that this motor has sat up for a while before you acquired her. At this point I don't think there is a crank seal problem, unless you notice oil coming out of the seal area.

    Your carburetor probably has not been cleaned in years and maybe before it was put up in the boat house. Would consider cleaning the carb with a kit. Read the machinist article about 6hp motors, he has an excellent section on how to do that.

    If your curious, here is a break down of your power head and the crankcase.

    http://www.**********/parts/search/BR...OUP/parts.html

    Since you motor has sat up a while, it will be good if you read this article about waking up a sleeping outboard. Some of the things you probably have already done.

    http://forums.iboats.com/engine-frequently-asked-questions-faq/awakening-sleeping-outboard-boatbuoy-158086.html

    If you haven't had your impeller or waterpump replaced, then I highly suggest replacing that thing, even though is currently pumping water. It is pumping water, right? After all those years they can just break apart while running and the owner not know it until the motor overheats and seizes up and cause damage to the cylinders and pistons.

    Have you check the compression on your motor? Poor/low compression or compression on each cylinder with a 10% difference on a motor can cause poor functioning/running. Low compression can come from blown head gasket from overheating to damage pistons or cylinders.

    Here is a link to tell how to check your compression. Hopfully your numbers will be high 60's to 90's PSI.

    http://forums.iboats.com/showthread....ht=compression

    I would make sure those spark plugs are gapped at 0.030

    A good way to assess a problem with a no running or poor running motor.

    You will see a lot of experience guys ask about compression, spark and fuel. (They are using a systematic approach to diagnosing an engine problem or problems....in this order)

    C= compression ( if your compression is low are uneven between cylinders >10% then others checks don't matter until the that is resolved)

    S= Spark (if your having problems with your ignition then you can have the cleanest carb and great fuel delivery but it will run bad or not at all)

    F= Fuel (if your carbs are not clean and fast/slow idle needle are not set right then it will run but like crap. If you have it set too lean then you run the risk of poor fuel/oil delivery and damage your pistons and cylinders then you run into the problem of C (poor compression from damage).


    Check out the forums secret file area, a lot of excellent reading and a huge thanks to all the guys that took the time to put it together.

    http://forums.iboats.com/johnson-evinrude-outboards/top-secret-file-updated-8-1-2012-a-299680.html

    http://forums.iboats.com/engine-frequently-asked-questions-faq-31/

    Hope this information helps you out. Will be out of touch for about 3 day or so, but if you have more questions or problems, please post and hopefully one of the experience guys will chime in to help you out. Good luck.

    cajuncook1
    Being cheap and not getting a manual will cost you hundreds or maybe thousands of dollars

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