spark plug (milky white coating )

[whaler80]

hi
have a 1980 johnson 100hp 2 stroke, one cylinder down with milky coat on that plug. engine starts and runs on three cylinder but dies at idle.
ideas anyone thanx

 

[tashasdaddy]

Re: spark plug (milky white coating )

check your compression. hopefully a head gasket, but your are definately getting water in that cylinder.

 

[ezeke]

Re: spark plug (milky white coating )

Is the coating dry or wet?

 

[whaler80]

Re: spark plug (milky white coating )

Is the coating dry or wet?

wet plug and top of piston

 

[ezeke]

Re: spark plug (milky white coating )

Tashasdaddy is correct. Water could also get in through a blown exhaust gasket.

Have you had an overheat?

 

[whaler80]

Re: spark plug (milky white coating )

Tashasdaddy is correct. Water could also get in through a blown exhaust gasket.

Have you had an overheat?

yes but about 6months ago!

 

[tashasdaddy]

Re: spark plug (milky white coating )

you probably toasted a gasket, and it's finally showing it's fury. do a compression check on all four, 100 psi or above, and with in 10% of each other. if one is down, pull the head and replace the gasket. it compression is even, then change the exhaust gasket.

 

[ezeke]

Re: spark plug (milky white coating )

The overheat may be the start of the problem. It can distort the head enough to cause the head gasket to leak. It does not take much.

Personally, I would buy a cylinder head gasket and take the cylinder head off and check to see if that is the problem or not. Once you open it, you can see what kind of conditions are there.

If you post photos on your picture site and link them here, the experts can give you a good idea what to do next.

When your engine overheats, you want to re-torque your head bolts as soon as possible and do a compression test. Otherwise it channels and usually just gets worse.

 

[ezeke]

Re: spark plug (milky white coating )

Last place again! I have to learn to type faster.:'(

BTW, If you cannot get to that pretty quick, you need to get some fogging oil and keep that cylinder well lubricated.

 

[whaler80]

Re: spark plug (milky white coating )

Last place again! I have to learn to type faster.:'(

BTW, If you cannot get to that pretty quick, you need to get some fogging oil and keep that cylinder well lubricated.

thanxs guys for the input, this is the way it went,removed head and found gasket to be ok! but piston badly chewed up chunks missing, lost a piston ring. so needless to say water coming from exhaust gasket least of my problems only a coincidence. so i dont think its worth spending $$$$$$ on rebuilding new cylinder,piston, head ect its a 1980 that i have had for 5yrs so hay can't complain. i'm going to replace with a 1990 90 evinrude that looks super clean and checks out , compress, runs goods and just serviced new impeller and all from local yard, thanxs again

 

[F_R]

Re: spark plug (milky white coating )

Not really a coincidence. Most likely explanation is that water has been getting in there ever since the overheat. Water causes rusted bearings and crankshaft. Rusted bearings cause disaster as they break up and go through the ports, taking the piston and rings with it. What you have is the disaster stage. Might take 6 months in fresh water, or two days in salt. Size of the leak counts too.

That is why I keep crying out that head and exhaust gaskets must always be replaced after any overheat situation. Just re-torqueing them is not enough.

 

[tashasdaddy]

Re: spark plug (milky white coating )

sorry to hear the out come. pull the engine apart. sell everything on ebay to help defer the cost of the new one. carbs, starter, lower unit, coils, stator etc. you will be surprized what you can make back. the 1990 is a good engine. i have a 1988 88spl, which is the stripped 90 with out the vro. super great engine.