Moisture on spark plug tips

[Coltrickle]

I have had much help on this forum for my 76 Johnson 70hp and thought I finally had her figured out.. I've replaced fuel lines, found the right prop, rebuilt the carbs and much more.. Now just for giggles I pulled my plugs and 2 of the 3 have this white almost wet baby powder/snotty look on them with tiny waterlike beads and the middle cylinder has what appears to be rust starting to form but it's wet also.. It has been humid here and it's been a week since I run it but I have owned many boats and never seen this after sitting a week! Any thoughts?

 

[Grub54891]

Well I would start with a compression test. And maby a leakdown test. First I would warm it up to clear any moisture. If that cyl is weaker you will have to dig in deeper to see if it's a headgasket. There isn't much more places to get water in there.

 

[F_R]

No Title

You must address this problem immediately, if not sooner. In all probability the exhaust cover is leaking and as a result squirting water in the exhaust ports. It WILL destroy the entire powerhead if it hasn't already. A common problem, it is because the exhaust cover baffle plate warps at even the slightest hint of overheating. Did I mention I've seen it too many times before?

 

[Coltrickle]

Grub54891 F_R I have done a compression test and have 120 on the top cylinder and 124 on the lower 2 cylinders.. I do not have the equipment to perform a leak down test.. I did however buy a merc classic fifty years ago that had this problem and had ruined the bottom cylinder.. Had about 60 psi while the top 3 had 115-120. I did not know this was a common problem on johnsons as well! Should I just pull the head gaskets and exhaust gaskets to be safe.. These exhaust gaskets look to have been replaced but the gaskets on the head still have the factory block paint on them. Thanks for your input.

 

[Grub54891]

Well The compression sound good.,Do what F-R recommends, The exhaust cover is an easy repair, and even it was done before, it may not be done correctly. I've actually seen them baffle plates warped, and actually rusted/burned through. Wish I remberd that before F-R did...lol

 

[racerone]

+++++1 on post # 3 --You must take action immediately.---Most newbies just do not understand how serious a problem it is when water gets inside the motor and attacks the precision bearings.---Take action !!

 

[F_R]

coltrickle, see what I mean? Somebody else attempted to fix it with just replacing the gaskets. You must address the warped plate, or it will just leak again.

 

[Coltrickle]

F_R Grub54891 racerone here are some pics after I pulled the head off.. I did not take any pics of the exhaust plate because someone put the rtv on real heavy and it tore the gaskets to pieces when removing. The head gasket looks great with no burn marks or water passing marks around the cylinder metal gaskets. However all 3 cylinders have water in them.. How can I check to see if the plates are flat and if they are warped how do I repair them. And is it all 3 plates that warp or just the one closet to the block?? Sorry for so many questions, just want to get it right!!

 

[Coltrickle]

I'm trying to load the pics

 

[Coltrickle]

No Title

@racerone [USER][/USER] [USER][/USER] Here are the pics so this leaking plate will put water into all cylinders?? who knew!!!

 

[racerone]

????---Are you aware of a " recirculating system " on that motor ???----Takes oil , or in this case water / oil mix and sends it from the bottom cylinder to the top cylinder.

 

[F_R]

Very true on the recirculating system, but in addition to that, you have the piston sloshing around (so to speak) in a cylinder full of water. It can get to the crankcase via the intake ports also. I know, it "shouldn't" but it does.

Check the plate for flatness with an accurate straight edge, paying particular attention to the areas around the ports. Notice how thin the metal is in those areas with no back up support and the bolts so far apart. Hey, I'm a card carrying Evinrude man, but I have to admit they screwed up on the design of that motor. My own Father-In-Law had two powerheads replaced under warranty, then gave up and traded his for a (ahem) Japanese motor.

I don't like the looks of the rust in the bottom cylinder. I wish you luck.

 

[emdsapmgr]

Any chance the water is being introduced through the fuel tank? You might want to sample the fuel at the bottom of the tank-just to eliminate that as the problem.

 

[Coltrickle]

racerone F_R emdsapmgr I have never heard of a recirculating system in this type of capacity?? But it makes sense.. If the plates are warped can I have a machine shop skim the surface to correct the warping and also how do you happen to know the torque spec and sequence for the head and exhaust plates? Is it like a car where you start on the ends and criss cross until you reach the center?? Thanks for the advice gentlemen!!

 

[F_R]

Sure the plate can be milled if you can do it without removing too much metal. But keep in mind that making it thinner makes the original problem worse. Part of the reason they warp is the thinness.

Head bolts are 168-192 INCH pounds. Retorque to 192-216 after motor test and cool-down. Begin in the center and spiral outward to about half torque, then repeat to full torque spec.

Exhaust cover is not specifically stated except general spec for 1/4" screws is 60-80 INCH pounds.

 

[Coltrickle]

F_R thank you very much sir! The knowledge on this sight is second to none.. I will post an update in a week or so after I have made the repairs!! Thanks again.

 

[Coltrickle]

F_R Thanks for the info. The knowledge available on this site is second to none. I will post an update after I make the repairs. Thanks again.

 

[Coltrickle]

F_R racerone I have ordered the gaskets to replace the 3 exhaust plate, head, water jacket head cover and thermostat gaskets.. I cleaned up all the exhaust plates and sprayed a light coat of black spray paint on the gasket surfaces then I put a sheet of 1000 grit sand paper on a surface plate and lapped the plates.. The plate that f_r posted the picture of above was warped slightly in near the exact same spots he indicated in the pic.. I took a long fine file and laid all the way over the plate and gently took the high spot down until it was flush all the way across.. 1. I hope this works.. 2 is there any other places the water could get into all of my cylinders that I should check before I put this back together?? Thanks for the help!!