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  1. #1

    Default propshaft seal leaking again or unburned 2stroke?

    I recently re-sealed this lower unit, and again I'm seeing black oil on the floor under the motor. The oil in the gearbox is still clean and blue. I smeared some of the black stuff on white paper to see if there was any remnant of the blue coloring but it smeared very brown.....no blue tint at all. Is it possible for this much unburnt 2-cycle oil to slowly drain from the exhaust leg?? This is my first through hub but none of my buddies have oil on their garage floors.

    I thought the seals went in pretty well.. The only thing I can think of is that I might have used sealant for the metal on metal part of the prop seals? Also I didn't replace the shift linkage seals but I don't think that would be leaking from the hub. Any opinions would be appreciated...This is a 1980 johnson 15hp by the way..

    Click image for larger version. 

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    Last edited by xltom; 05-17-2011 at 06:46 PM.

  2. #2
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Looks like residual from combustion. What type(brand) two stroke oil are you using? When is the last time you de-carbonized your engine?

  3. #3

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by Docksidemarineservices View Post
    Looks like residual from combustion. What type(brand) two stroke oil are you using? When is the last time you de-carbonized your engine?
    Pennzoil marine Premium Plus (TC-W3?) from wal-mart. Gear box is full of Quicksilver sae90 marine gear lube also from walmart. Jeez I wonder if I replaced all the seals for nothing.. Do I need to build a pressure tester or will checking the lube religiously be OK? I've got a weekend trip planned for some high lake trout fishing....

    Never de-carbonized.... I'm not familiar with that procedure..

  4. #4

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Now that I'm thinking about it,... both times I saw this stuff on the floor were after trolling for long periods of time at low rpms. It took about 10 days for oil to make it to the floor in both cases. Any of you mechanics know a slick way to be sure what kind of oil I'm looking at here? Has anyone ever seen this much 2cycle build up and drip from an exhaust?

  5. #5
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Just guessing is not good enuff.-------------Pressure testing of the lower unit before and after a reseal job is the only way to go.-----------------Is the thermostat working properly on this motor ???------If the lower unit passes a pressure test , then what you are looking at is from the exhaust.

  6. #6

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by racerone View Post
    Just guessing is not good enuff.-------------Pressure testing of the lower unit before and after a reseal job is the only way to go.-----------------Is the thermostat working properly on this motor ???------If the lower unit passes a pressure test , then what you are looking at is from the exhaust.
    Fair enough. I'm working on a pretty tight budget right now. I'll look for a pressure tester..... got a link? What do I need to convert to the threads on the LU drain hole?

  7. #7
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Pitch black drainage is simply the excess gas/oil mixture draining down thru the long soot coated exgaust housing. To ease your mind, simply loosen the L/U drain plug somewhat and compare the coloration.
    We occasionally have questions. If you fail to answer, it may affect ours.

  8. #8
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Stop using that crappy oil in your engine. Buy Johnson/Evinrude 2 cycle oil. Your engine will run cleaner. Get a can of "Sea Foam". http://www.seafoamsales.com/images/s...f-mt-hover.jpg

    Run the engine up to temp, shut her down, remove all the spark plugs, tilt the engine up and pour a quart evenly through all the cylinders screw the plugs back in hand tight and let it sit for two days. After the two days is up, remove the plugs and turn the engine over a few times, reinstall the plugs and run on a set of muffs. Spread out a tarp to catch all the unburned penzzoil. Empty out the Penzzoil and by manufacturers oil for your engine.

  9. #9

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Thanks guys.. I found most of the parts for a pressure tester but I'm short the drain hole fitting and a bicycle pump. I'm pretty sure that it's not gear lube.... will switch to johnson/evinrude 2stroke and monitor my gear lube. I'll keep working on the pressure tester as this is not the first time I've had need for one...... I'll de-carbonize the motor soon too.

  10. #10

    Default Re: propshaft seal leaking again or unburned 2stroke?

    You can use the tubing and fitting from a lower unit oil pump to complete your pressure tester. West Marine (and other marine stores) carry them. Here is a link and a picture. http://www.westmarine.com/webapp/wcs...4673&langId=-1Click image for larger version. 

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  11. #11

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by michael_l View Post
    You can use the tubing and fitting from a lower unit oil pump to complete your pressure tester. West Marine (and other marine stores) carry them. Here is a link and a picture. http://www.westmarine.com/webapp/wcs...4673&langId=-1Click image for larger version. 

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    Hey cool, any idea which fitting johnsons use?... they have 8mm and 10mm.

  12. #12
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Now if you had a British Seagull, this is all completely normal

    B

  13. #13

    Default Re: propshaft seal leaking again or unburned 2stroke?

    xltom,

    I beleive OMC is 10mm and Yamaha is 8mm.

  14. #14
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    A 1980 Johnson lower unit has drain / fill plugs with a -----------------3/8-NC thread------------------Guaranteed !!!!

  15. #15
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    When you buy parts Make sure you support this host site first and Michael please recommend parts and supplies from here Pump and costs less

  16. #16

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by Cliff C View Post
    When you buy parts Make sure you support this host site first and Michael please recommend parts and supplies from here Pump and costs less
    Great price.... are you sure the omc fitting comes with it? The ad only says it has fittings for nissan yamaha tohatsu and honda.

  17. #17
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by xltom View Post
    Great price.... are you sure the omc fitting comes with it? The ad only says it has fittings for nissan yamaha tohatsu and honda.
    If you are going to use the fitting on the end of the fill pump as a pressure tester, as I do, You will need to purchase one with an metal fitting on the end of the hose with an o-ring seal. Not the plastic one. Sorry Cliff C, you will have to hit the west marine store near you. The standard pump will fit your lower unit. No adapter needed.

  18. #18
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    its neoprene so it will for all thread types

  19. #19

    Default Re: propshaft seal leaking again or unburned 2stroke?

    It will fit, but it will not work as a pressure tester component which was the question. And Cliff, I do support this host site as I have personally purchased from it. Sorry if I offended you.

  20. #20
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Michael,

    No worries my friend this task I have isnt always pleasant and keep up the good work!

  21. #21
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Well, this has probably gone on far too long but here is my two cents worth, not that it means a lot.

    About 20 years ago I bought my Mate's motor. He had it from new.

    I was always on at him to change his prop to a lower pitch as max revs were around the lower of 4000rpm at any stage. His boat was too bloody heavy...........

    I ended up getting it and, visualise a prop nut obscured by carbon and oily crap. It never did its higher RPM. Black goo everywhere because of unburnt oil.

    Put it on a light hull, 12 mnths later clean as a whistle running maxed out as Rpms for Hp dictated. I used no special hyped up oils only anything with TCW3 registration. I used no additives for a quick fix.

    It is on a back rack at the moment waiting to fight again.

    Does this engine rev out?

    B

  22. #22

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by collector_inspector View Post
    Well, this has probably gone on far too long but here is my two cents worth, not that it means a lot.

    About 20 years ago I bought my Mate's motor. He had it from new.

    I was always on at him to change his prop to a lower pitch as max revs were around the lower of 4000rpm at any stage. His boat was too bloody heavy...........

    I ended up getting it and, visualise a prop nut obscured by carbon and oily crap. It never did its higher RPM. Black goo everywhere because of unburnt oil.

    Put it on a light hull, 12 mnths later clean as a whistle running maxed out as Rpms for Hp dictated. I used no special hyped up oils only anything with TCW3 registration. I used no additives for a quick fix.

    It is on a back rack at the moment waiting to fight again.

    Does this engine rev out?

    B
    I believe so.. keeps up with my buddie's(=mate... hehehe!) newer merc 15. I believe the problem is and will be that this motor idles/trolls at low speed all day long. If I could get the trout to bite at 20mph this might be a non-issue, and wouldn't that be fun! I clocked my top speed at 21mph with a cheap portable gps(tom tom). This was on my 15ft welded aluminum v-hull(gregor). Hull weight is approx. 200lbs and captain's weight is 260lbs(heheheeee!). Maybe a prop with less pitch would allow me to troll slow with slightly higher rpms......
    Last edited by xltom; 05-21-2011 at 09:47 PM.

  23. #23
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Love that! Now what you need is our special 20mph Rainbow Trout in our southwest waterways Mate!

    They are special as when they take the lure and accelerate from 0 to 20Mph, their lips do not fall off and are accounted for that evening on a BBQ! Should export them eh?

    So, you have 15Hp with that weight correct? If so, unless a trolling plate or a prop massive re-pitch, you will have this problem with needing a pad attached after use.

    You could try two heat ranges up in plugs but do not cut back on oil mix.

    Bulk buy Pads may help.

    Also, instead of applying WOT, with that load, use your GPS to find the max speed at lowest throttle. That way your motor is not maxed out in advance at low revs.

    In effect, the motor will be at the correct revs for the advance and will, everything being sweet, burn clean.

    Give that a go.

    Excellent reply of yours!

    Regards

    B
    Last edited by collector_inspector; 05-22-2011 at 02:57 AM.

  24. #24

    Default Re: propshaft seal leaking again or unburned 2stroke?

    1. They have rainbow trout in kangaroo land? Are they native?
    2. You think the 15hp is too small for my boat? Haven't even mentioned battery, passengers, fuel etc....
    3. Are you suggesting I put a maxi-pad on my motor??!! LMAO!!!
    4. How would I go about finding plugs "2 heat ranges up"... ask the napa guy I guess???
    5. I doubt I can resist the urge to give her WOT but I don't think runnung fast is the problem anyway.
    6. Not sure what you mean by "advance"... is that aussie talk or mechanic lingo? I don't speak either fluently.

    Thanks for replying to my thread... It needed some info on running cleaner. Sorry for the bullet list... and my ignorance

  25. #25

    Default Re: propshaft seal leaking again or unburned 2stroke?

    http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1980&hp=15&model=J15RLCSD&manufactu rer=Johnsonžion=Gearcase

    Looks like they have a few different props for my motor here... which would be appropriate for my application??

    My plugs are: L77JC4. What would be the correct hotter plug?
    Last edited by xltom; 05-22-2011 at 09:25 AM.

  26. #26

    Default Re: propshaft seal leaking again or unburned 2stroke?

    I talked to a mechanic today. His advice was quite different than the advice I recieved here. First off he said hotter plugs were a really bad idea. They could burn up the motor. He also said switching brands of 2-cycle oil probably wouldn't help either. A new prop isn't the answer either....

    He said if someone brought him a motor with this problem the first thing he would check is the carb. He was surprised nobody mentioned that here. The carb may be allowing too much fuel to enter the cylinders if a valve is stuck. The next thing he would check is the ignition system....test the voltages everywhere... before and after the control box, coils and plug wires...

    His explaination seems to make alot of sense... unfortunately I have no idea how to test the voltages on the ignition system....

    anybody have specs/voltages I should be seeing with my ANALOG multi-meter(digi won't work, too slow)? Or better yet a walk-through from a repair manual? My model# is J15LCSD. Thanks.

  27. #27
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    The original question was -----gear oil or unburned mixed oil---------------------Have you posted results of a lower unit pressure test ?????????????--------------------If that is " pass " then you look for other problems -------------------This is not " rocket science "-------------------------If spark jumps a gap of 7/16" with a snap you can hear , then there is no further ignition testing needed !!

  28. #28

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by racerone View Post
    The original question was -----gear oil or unburned mixed oil---------------------Have you posted results of a lower unit pressure test ?????????????--------------------If that is " pass " then you look for other problems -------------------This is not " rocket science "-------------------------If spark jumps a gap of 7/16" with a snap you can hear , then there is no further ignition testing needed !!
    No pressure test.. I'm pretty sure it's 2-cycle oil. Sorry, I had already moved on from the original question.. maybe I should have started a new thread: How to diagnose the cause of unburned 2-cycle oil in my exhaust and fix it?

    Cool tip on the spark test but how to acomplish this? Hold the connected plug about 7/16" from the block and have a buddy yank the pull starter? Sorry I am no rocket scientist!

  29. #29

    Default Re: propshaft seal leaking again or unburned 2stroke?

    Quote Originally Posted by racerone View Post
    Just guessing is not good enuff.-------------Pressure testing of the lower unit before and after a reseal job is the only way to go.-----------------Is the thermostat working properly on this motor ???------If the lower unit passes a pressure test , then what you are looking at is from the exhaust.
    Hey, why did you ask about my thermostat? I have no idea what it does...well I thought thermostats on outboards controlled the amount of water they pump.... but obviously my impellor spins at the speed of the drive shaft so I dunno. This is the first motor I've had that has one(if it does have one). Thanks

    EDIT: Dude I think you're on to something there! I just checked what a thermostat does... my motor pees hard all the time! It's probably at too low of an operating temp while I'm trolling ALL THE TIME......
    Last edited by xltom; 05-26-2011 at 04:58 PM.

  30. #30
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    Default Re: propshaft seal leaking again or unburned 2stroke?

    Simple--------------- after 40 years of outboard experience , I have seen those thermostats stuck open and the motor will run cold .------It is up to you to respond to questions and do your trouble shooting.--------------------When you put your hand on the cylinder head , is it getting warm.-----------You should be able to put your hand on it for at least 5 second or so.----------------By the way the waterpump indicator should flow all the time , does not indicate thermostat operation on your model !!!

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