This is bad...but how bad?

[Merc90HPnewbie]

Ok I was on the river 2 weeks ago and I didn't notice I had collected a LOT of seaweed around the lower unit (BTW this is a 1984 or 85 Mercury 90HP inline 6cyl outboard). <br /><br />The engine started sounding wierd (there was no overtemp alarm by the way) and when I turned around to look at it, it was shooting steam and blue smoke out of the cooling hole and smoke was coming up around the covers (shudder). I shut it down and trimmed the motor up, there was enough seaweed stuck to it to fill a 5 gallon bucket. I guess it covered up the vents and caused an overheat. I got towed back to dock and that was the end of the day. I got home and did a quick compression test- got about 100-120 on all cyls (I know this is not great but it is in line with what I've measured before). I was suprised the engine even turned over at that point.<br />I started to disassemble the lower unit, thinking that the water pump impeller probably shredded itself and I'd have to replace it(never got a chance to finish pulling the lower unit).<br /><br />Anyway, fast forward to today where I figured I'd see if the thing would run and 'pee' to avoid having to take the L/U off. So I hook up the muffs and start it up and... it runs! That's the good news. While taking the muffs off I noticed some liquid dripped on my head. It was clear but it wasn't gas.. it didn't smell like anything... ARGH! it must be water...<br /><br />I pulled each spark plug and they looked 'ok'. Some were oily but they seem to always look like that when I first start it. I put the muffs back on and took the motor covers off. With the motor running, I can see there's water dribbling out around the #2 spark plug. Bad news. Oddly the #2 plug didn't look 'steam cleaned' as plugs sometimes do when there's water in the cyl (so I've heard) but I was only running the motor for a few minutes.<br />I told the wife the motor was likely totalled (as in, would cost more to fix than the whole boat cost us in the first place). But I'm not 100% sure about this. Is there anything I can do or try, or should this motor just go to the junkyard?<br /><br />Thanks<br />-Merc90

 

[Laddies]

Re: This is bad...but how bad?

you have burned the wayer jacket cover gasket out around the plugs pullthe cover off and replace it, ck and make sure the plate is not warped the leak commonly on inline six no big deal--bob

 

[andrewkafp]

Re: This is bad...but how bad?

Sounds like water cover. Common that these drip a bit. Just clean it up use put a bit of J.B or silicone around the plug hole (Keep it off the threads.)<br />Or you can take a chance on replacing the gasket, which most likely involves P/H removal.<br />This is how I fixed mine (leak right near the thread).Remove plug washer and drill the inner diam out a few thou..Line the washer with RTV silicone and use an old plug to screw it in.<br />Because the washer is now slightly bigger than the plug thread, it won't come out with the plug every time and instead will seal that area. When you change plugs, discard the plug washer as it's alredy there.

 

[NathanY]

Re: This is bad...but how bad?

That motor is totaled, you should take it off your boat and send it to me right away. Sorry there is nothing you can do to fix it. <br /><br />Not a problem, a new gasket will have you fixed right up. If you cant get to the bottom 4 bolts to take the water jacket cover off, follow unicorn's advice w=ith jb weld. Would try the silicone first though.

 

[Clams Canino]

Re: This is bad...but how bad?

It's just the water jacket cover. I'm with Unicorn no need to pull that cover, particularly if only one hole area is leaking. For all you know it was like that BEFORE the overheat and you just weren't looking for trouble.<br /><br />Water can't get into the cylinder from there.<br /><br />-W

 

[Merc90HPnewbie]

Re: This is bad...but how bad?

Wow ok so I was way off. I figured something went very wrong and cooling water was leaking into the cylinders- I thought what I saw was water squirting out around the plug (though I didn't quite see how it was possible for water to work all the way around the threads of a fully seated plug...)<br /><br />Thanks to you all for setting me straight. I looked at the manual late last night based on your replies-I was pretty bleary eyed so maybe that's why I didn't quite see how the cover, gasket, PH, etc fit together. I will take another look at the book. But it sounds like there's two ways to fix this- taking the water jacket cover off (Unicorn says- this involves power head removal?!) vs patching the leak locally. I will try the 'sealing the area around the plug hole' with silicone trick. <br />Clams; if this was my car, you'd be right (I hate working on cars and I ignore mine until things are really bad) but I am sure that this leak was not present before...not that it matters! <br /><br />So, let's say I patch this and it later goes bad. With a dribble of water coming out of this area (as long as the motor is peeing and sending water out of the leg), this should not be a huge problem right? Just something to check on every few months or so?<br /><br />Thanks yall and here's to getting back on the water.

 

[PierBridge]

Re: This is bad...but how bad?

Water jacket R and R is about 3 hr's labor plus the gasket.<br /><br />Well that's what I paid anyway...

 

[Clams Canino]

Re: This is bad...but how bad?

Originally posted by Merc90HPnewbie:<br /> So, let's say I patch this and it later goes bad. With a dribble of water coming out of this area (as long as the motor is peeing and sending water out of the leg), this should not be a huge problem right? Just something to check on every few months or so?

Yup.. it's a minor leak. Worst it can do is maybe get on / into a plug wire and cause a misfire or something. Clean it WELL before adding the silicone will help it stick.<br /><br />-W

 

[run13.1miles]

Re: This is bad...but how bad?

Here is how I fixed my leak. Secure a piece of alum. tubing the same diam. as the "hole" around the spark plug.Cut it approx. one half inch long.Put some sealer around it and gently tap it into the "hole" until it bottoms. I sealed all 6 of my spark plug "holes". Now no water leaks!

 

[jimmbo]

Re: This is bad...but how bad?

You don't have to pull the powerhead. You will have to move the bottom cowl out of the way, which will require some disassembly and removal of the front and rear cowl supports<br /><br />

 

[andrewkafp]

Re: This is bad...but how bad?

Unicorn said "Most likely" to P/H removal.Reason is if you snap the lower bolts.. You can't drill them out very well with the Powerhead on, but if the lower cowling will swing away, you might be lucky.<br />Other things can cause the leaks to worsen like new W/Pump(more pressure) and running harder.<br />If they still drip a bit.. coat the exposed steel end of each plug with clear auto laquer to prevent rust.<br />Run13... Very innovative, but risky if it didn't work.. But it DID.

 

[KCLOST]

Re: This is bad...but how bad?

I'd still replace the impeller....By the way...

 

[Merc90HPnewbie]

Re: This is bad...but how bad?

I'm guessing the 'cowl' is that annoying oval shaped thing that encircles the whole motor which I curse at because it gets in the way when I try to remove the bottom spark plug. (the item tilted down and out of the way in Jimbo's picture). I never did understand why it had to be placed like that or how to take it off. <br /><br />Unicorn; this motor has only seen fresh water and the bolts/screws/etc are in pretty good condition. Do I still have to worry about busting a bolt head off just due to repeated heating/cooling and age?<br /><br />Also, there's something I don't understand about your idea- you say to open up a spark plug washer ID so that it doesn't come out with the plug. I don't see how this would seal anything though because it's OD is still the same, and the water comes out with the plug and washer installed normally.... so is it just the silicone around the washer that keeps the leak plugged? Isn't the water under a good amount of pressure?<br /><br />Thanks again to all who posted, sounds like this is a common problem, I just never heard of it.

 

[Clams Canino]

Re: This is bad...but how bad?

The water is at under 10 pounds of pressure. The silicone seal is the key, the washer is just to help the seal and more importantly to not disturb the seal when you remove a plug. Clean the area WELL before doing it.<br /><br />What Unicorn gave you was not "an idea" it's "the easiest solution" to a small leak on that cover.<br /><br />The risk of breaking a bolt is ALWAYS present on that cover. Also, there is no way to remove that lower cowling without pulling the powerhead.<br /><br />-W

 

[Merc805]

Re: This is bad...but how bad?

Clams has it spot on.<br />The plug washer has interference when removing, and will at most times be forced our with the plug. By making the inner diameter very slightly larger, and coating it with silicone, the plug will compact it down and force silicone into the innermost area of the leak. When you remove the plugs, the washer will be un-disturbed and the seal will remain unbroken. If you install new plugs, discard the new washer as leaving it on will affect the depth that the plug seats. <br />Also agree on the bolts. It's liike the Dirty Harry quote "Gotta ask yourself.. Do I feel lucky" ? <br />If you don't have a lot of regard for that motor, you could drill or cut away part of the cowling to allow for socket and re-drill if needed. Then get some rubber deck plugs to push into the holes.. A bit rough, but the choice is yours.

 

[Merc90HPnewbie]

Re: This is bad...but how bad?

Ok so I wanted to try this out. I bought a new set of plugs and went to try to remove a washer from one of the old ones. The things have a strange (triangular?) profile and look like they are pressed together from two seperate pieces after the plug is made. I couldn't unscrew the washer off the plug and when I tried to pop it off it just bent up and wouldn't seal (and I couldn't flatten it out again because it's not a regular flat washer). So I'm wondering:<br /><br />-Would silicone seal up this problem alone, with no washer to back it up?<br /><br />-Is there someplace I could find oddly shaped washers like this? I'd punch one out of a soda can or something but I don't have the right tools. My other ideas are to look through other plugs to find a normal flat washer that is removable and has the right ID and OD.

 

[Clams Canino]

Re: This is bad...but how bad?

Try to pull a few of them from the old plugs. You can get them off with creative prying and patiance. It's OK to hammer them flat and drill them later too. The washer in the case we're talking about is just there to shim the plug tip out and help preserve the seal around the water jacket.<br /><br />If all else fails, put the plug in a vise and cut it off behind the washer.<br /><br />-W

 

[andrewkafp]

Re: This is bad...but how bad?

It's easy.. Hold plug with one hand. Hold washer with needle nosed pliers, turn plug anticlockwise. Washer will follow thread and come off.. What Outbored has done, is adhere a permanent washer to the water cover hole and enlarged the hole so the plugs don't remove it each time you take them out.