Logo
FULL SITE MENU

60 hp Mercury, 1 wet plug

K

Kurtkenway

New member
Allright guys I'm in need of some engine help.
I recently purchased a 1985 Doral with a 2 stroke 60hp Mercury. I am having issues with the top cylinder not burning the fuel mixture. Every time I run the boat I have a on of un burnt oil come out of the exhausts. Here's what I've done , new fuel mixed at 50:1, three new plugs, compression on all ports is 135, visual spark is good. I ran it for 5 min then pulled the plugs, the top plug was wet, middle dry bottom dry. So I figured it was coils, so... I took the number one coil and connected it to the number two spark plug, and hooked the number one plug to the second coil(obviously kept the firing pattern the same). Now the wet spark plug stayed in the number one position. Any idea why I would not be getting combustion in that cylinder even after switching coils.
 
Never looked at this. I am new to 2 strokes, so a lot to learn. I will be removing carbs again to look. I am still confused how two carbs feed the 3 cylinders so removing the carbs to look at the reeds should answer this.
 
If it is the reeds you may observe fuel getting blown out of the top carb (from the throat).

Also, look for a gloopy mess (kinda like fogging oil) coming from under the flywheel and coating the power head - that could be indicative of a toasted upper main crank seal - they are known to go...
 
Top carburetor feeds #1 and partly ( half ) # 2 on that.-----------Bottom carburetor feeds # 3 and the other half of the air / fuel supply for # 2.
 
I have not noticed any fuel getting blown out fo the top carb. Also no mess around the flywheel, everything comes out of the exhaust ports. The amount of unburnt oil that comes out of the prop exhaust after it has been turned off is alot. I have attached pictures of the three spark plugs after 5 min of running. Top plug is the wet one, other two obviously the dry middle and bottom.
I also attached pictures of the oil mess after it has run.
IMG_8027.JPGIMG_8029.JPGIMG_8028.JPGIMG_7978.jpgIMG_7987.JPG
 

Attachments

  • IMG_8026.JPG
    IMG_8026.JPG
    44 KB · Views: 255
The top plug looks normal, the other 2 look abnormally clean. Like they've been steam-blasted from a water leak. In fact, is that a water droplet I see on the 2nd plug?

The gloppy goopy mess you see is not indicative of what's happening in #1 cylinder. It's coming from unburned fuel/oil mix, mixing with water.

You might want to do a "drop test" to see which cylinders are "kicking". Pull one spark plug wire, stick a spare plug in the boot and ground the spark plug against the metal frame or block. You can also check for spark while you're at it. See if it runs better, worse, same. Do that for all three and then you'll have a better idea which cylinders are actually combusting.

Most likely you've got perished exhaust manifold gaskets (or a perforated exhaust baffle) and they're spraying water into the exhaust ports of one or more cylinders.

HTH & let us know what you find......ed
 
I will try to do the drop test this weekend. Keep in mind those spark plugs where brand new out of the box, and only ran for the couple min.
Now that you mention the water in there, I have good flow out the cooling hole but also see water trying to spray out of the exhaust at the top of the leg (tried to take a picture of it). Not sure if this is normal or not.
imagepng
 
The water dumps down the leg, and some is taken up into the exhaust reliefs. This is normal. You'd see more water coming out of those when you're in the water, since you have some exhaust backpressure.
 
If u have water droplets on plugs ,check your compression on the three cylinders after checking exhaust manifold gaskets and exhaust baffle as ed instructed.Bad compression sign of damaged head gasket or head allowing water to enter combustion chambers thus cleaning plugs as shown in thread #6
 
i had done a compression test earlier and found that I had 135-140 on all cylinders. Let's say I am potentially getting water back in, would the boat still run decent with possibly going into two cylinders ? It does seem to idle decent and does run at high rpm, just smoked alit more. Under load on the lake it did t have much power but I'm not taking back on the lake until I get the oil under control. Little hard on the lake.
 
The water ingestion may not have done a lot of damage to the engine yet, but unfixed it will be much more harmful to your engine than to the lake!

The only places water can come from on these is from a cracked block, bad lower crankshaft seals, and exhaust manifold. Your compression readings are high enough where it'll run ok, so not likely it's the block. You have water in more than just the bottom cylinder, so probably not the lower crank seals, which usually only suck water into the bottom cyl.

I'd bet on exhaust manifold issues. This motor does not have an inner exhaust passage water jacket as do the Inline Fours and Sixes, so the leakage would come from problems with the exhaust baffle itself, or the gaskets.

If you don't have a Salty Dog, the bolts shouldn't be seized in place.

If any bolt doesn't break free with normal force on a wrench, don't force it any further. It must be heated with a propane or MAPP torch until it releases.

Sometimes the combination of shock and heat works well to loosen a stuck bolt. Take a pin punch or other suitable tool, strike the head directly using the punch and a sharp blow from a hammer. Do the same thing carefully, to the flat sides of the bolt. This jars the corrosion products loose and gives a better chance of getting the bolt out without breaking.

If a bolt doesn't want to come out no matter what, better to drill out the head and remove the manifold. Then you'll have a longer stub of the bolt to get Vise Grips on, and you can put heat right on the block where the bolt threads into. 9 out of 10 they'll come out doing this.

Worst case, you'd drill & tap the busted bolt to fit a Heli-Coil insert.

You can order new gaskets here, just look 'em up according to your motor's serial number.

HTH & G'luck with the repairs........ed
 
Just and update, got the exhaust manifold pulled off and the gaskets were there but not much of them. I have new ones on order hopefully in before Friday. Once I have then replaced I will let everyone know the results. Thanks again.
 
hi - i just also tore down my 60hp mariner with lower wet plug..

first thing u cant try is swap the coils, leave trigger wires in place, just swap the wires from switchbox to coil, and plug wires to plug - if yours is like mine the top coil fires bottom cyl (#3), middle cyl 2, and bottom coil top cyl (#1).. ie use a good coil on the wet plug and put the coil from the wet plug on the other cylinder, if the other plug is now wet u have a bad coil or plug wire / connection (very unlikely tho). Running motor at night will also reveal gremlins, and sparks around that area = bad!

ALSO/OR do an open spark gap test.. I made one with 2 brass screws and some plug fittings - Used this inline with motor running, it should spark a blue tazer like arc!

If the same plug is still wet i would suspect the switchbox as u have just changed the wires and coil and still same plug - so that rules out anything from coil to plug..


have u done a compression test?

and how does it run?



here is a simple reed valve test:

Remove plugs and possible carb cover or carbs - easier but not necessary)
Find bottom dead center thru plug hole (when piston is not moving and furthest down the hole, only turn flywheel by hand with battery disconnected and pref some water on muff to keep impeller wet..
Now get a friend to watch the carbs from front of motor, and get a short piece of garden hose and take a few big puffs from a pipe or cigarette and blow it down the plug hole - make sure the piston is at BTDC, if smoke comes out of carbs reeds are leaking.. blow a good few mouthfuls down the cylinder!! i dont smoke and this was quite disgusting - luckily mine were fine :)

also - bad reed valves will show gas blowing back thru carbs while running, quite obvious..
 
Kurtkenway said:
Just and update, got the exhaust manifold pulled off and the gaskets were there but not much of them. I have new ones on order hopefully in before Friday. Once I have then replaced I will let everyone know the results. Thanks again.
Click to expand...


as read elsewhere, use a thin skin of permatex ultra on the exhaust gasket on both sides! not the cheap HF junk RTV, permatex ULTRA, comes in grey iirc.. let it set overnight before running and clean surfaces with thinners! esp around exh port, gets hot there and eats gaskets!
 
Ok guys, I have replaced the gaskets and fired it up in the back yard. Still smokes like crazy, the idle speed came up about 300rpm, and not much black slime coming out. Looks mainly like what would have been cleaning out of the exhaust. Now ran it for 3-4 min and pulled the plugs. Same as before top cylinder is dirty the other two clean. Only thing I noticed is I have small amounts of gas dripping off the bottom of the carb. As you will see in the picture.
Also did a drop test and couldn't notice a difference from either 3 plugs to which way it would run better. Obviously a difference compared to all three hooked up but nothing different when I pull one off.
Any other thoughts. Also the idle set screws on the side how does a guy know where to set them?
imagejpeg


imagejpeg
 
Kurtkenway said:
Ok guys, I have replaced the gaskets and fired it up in the back yard. Still smokes like crazy, the idle speed came up about 300rpm, and not much black slime coming out. Looks mainly like what would have been cleaning out of the exhaust. Now ran it for 3-4 min and pulled the plugs. Same as before top cylinder is dirty the other two clean. Only thing I noticed is I have small amounts of gas dripping off the bottom of the carb. As you will see in the picture.
Also did a drop test and couldn't notice a difference from either 3 plugs to which way it would run better. Obviously a difference compared to all three hooked up but nothing different when I pull one off.
Any other thoughts. Also the idle set screws on the side how does a guy know where to set them?
Click to expand...
 

Attachments

  • image.jpg
    image.jpg
    25.4 KB · Views: 270
  • image.jpg
    image.jpg
    28.9 KB · Views: 1,433
That's a good sign when the rpm came up. But I doubt you'd see much difference in any of the plugs after only a few minutes of idling. You'd have to get it out on the lake for a full power run then read the plugs afterwards. And Permagap plugs are notoriously hard to get good readings off of.

The carb drip, if it's doing that when it's running, is definitely a problem. Mostly a fire hazard but then you don't want that fuel/oil mix dripping all over anyway.

Might be some "fluff" in the float needle, a maladjusted or "sunk" float, many things can cause that. A large leak might spill out of the carb throat, and one like that would definitely make the cyl's run rich on that carb. Might also mask the results of a drop test.

So you might need to get that issue under control before running. Or run it a bit and see if it works itself out.

Far as carb adjustment goes, you have to set the idle speed and mixture in the water, warmed up & in gear. Adjust each carb idle mixture needle for smoothest idle. Then try a fast takeoff and if it stumbles, turn each carb needle 1/8-turn rich (CCW) then see if it'll accelerate. If not, try another adjustment. It'll end up idling a bit on the rich side (i.e. "lumpy") since these carbs have no accelerator pump and if you run 'em Lean n' Clean, they'll bog on takeoff. Just a compromise.

One last thought, after you've run it a bit, turn it off and feel the metal base of each spark plug. They should all feel quite warm (or Hot!) and if you have one that's drastically colder than the others, it's not pulling its load. If they're all nice 'n toasty, that's a good thing.

Anyway, see if any of that helps and let us know how it goes........ed
 
Hardest thing is I dont want to take it out on a lake as it still releases a lot of black oil into the water. As i have it running in a rubbermaid tube and you will see what it leaves behind after it runs.
I adjusted the carb set screws as well as the one spark stop screws, as the boat would idle at 1800 rpm. I am not sure what they are meant to idle at but this seemed very high. I got it down to about 800 and the carb stopped dripping off the bottom.
I have almost hit my mechanical abbilities so I believe I will be looking for a shop to take it to as no matter what I do she puffs out smoke and oil.
IMG_8093.jpg
 
Hello,
I have been following this thread with much interest, since I own a 60hp Merc (serial no. a110380) with identical plug colors. I was interested in fastjeff's top seal comment. I had read somewhere where they ran a long sheet metal screw into the top seal and pulled it out (any comment on this method would be appreciated).
I also went out to the part area of this site and looked at the crank case breakdown. The top seal was item 22 and the lower seals were item 27. There was no listing for item 22, did I miss something? Do you use item 27 on the top and the bottom? A discussion of replacing the top seal would really help me.
19.jpg
 
I have a 50hp 1990 Triple which is pretty much the same motor as your Mariner. All the crankshaft seals are the same. On the diagram for my 50hp, the P/N for the upper crank seal (22) is listed, whereas number for the lower crank seals is missing. Go figure!

I wouldn't be too suspicious, though, of a top seal unless it's leaking oil under there. They don't seem to go bad as often as the lower seals, which are subject to much more strenuous conditions.

At any rate, the upper bearing cap is a snug fit in the crankcase but will pull out without splitting the case.

You need to use some sort of puller on the cap since the mounting "ears" are quite fragile and could be easily broken. The cap will pull straight up, out of the upper crank bearing & crankshaft.

If you do pull the cap, you also need to replace the O-ring. Lubricate the O-ring with some Mercury multi-purpose grease or light lithium-based before reinstallation.

Make sure you mark the cap for proper orientation. As I recall you can only bolt it up one way anyway, but you might as well start out having it correctly aligned before you reinstall.

Probably should start your own thread on this, before we hijack this one!

HTH...........ed
 
Changed the top seal on mine at the boat ramp! It's that easy to do.

Pop the 'wheel, remove the trigger coil and stator, drive a couple of self-tapping sheet metal screws into the old seal, and gently pull it out with pliers.

Jeff
 
I myself don't see top seal effecting #1 cylinder and making it rich if it was leaking it would been leaner.
 
Last edited:
fastjeff said:
Changed the top seal on mine at the boat ramp! It's that easy to do.

Pop the 'wheel, remove the trigger coil and stator, drive a couple of self-tapping sheet metal screws into the old seal, and gently pull it out with pliers.

Jeff
Click to expand...

Jeff, crude but effective!!! :p
 
Well, Kurt - did you resolve the original issue with one wet plug? Faztbullet effectively killed the top seal idea with sound logic.
I am still looking for a reasonable solution.
 
Back
Top