1985 Johnson

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Rbsgfd578

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I was just wondering.I changed the plugs in my 1985 Johnson V-4 90hp and 1 of the plugs had a yellowish froth on it.The motor is running fine and all cylinders are firing strong. What I was wondering is could it be just unburned oil and gas on that cylinder,because before I changed my plugs approx. a couple of hours prior I had turned the motor over a few times to make sure the battery was charged good.
The froth kinda looked like the crud that comes out of your exahust when your running on muffs.
Just wanting to check on this so if it is a problem I can catch it before it gets worse.
Thank you for all your help
 
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steelespike

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Re: 1985 Johnson

Could be nothing could be a slight headgasket problem.
Run her a couple of hours and take a look at the plugs.
might appear whitish or possibly a little rust.Sometimes water in the cylinder will make the plug appear erxtra clean.If nothing you are probably ok.
 
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F_R

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Re: 1985 Johnson

Don't ignore the froth. It probably is water getting in the cylinder, which will destroy the powerhead. If it is getting water intrusion, you must find the problem and fix it. The motor sees water as water, whether from a bad gasket or complete submersion.
 
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emdsapmgr

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Re: 1985 Johnson

As a precaution, you might want to check the VRO tank to be sure there is no water in the tank-being sucked up into the engine.
 
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Rbsgfd578

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Re: 1985 Johnson

I dont have a VRO tank on it..Im runnin premix 50:1
 
tashasdaddy

tashasdaddy

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Re: 1985 Johnson

get a compression guage and test the compression on all 4 cylinders. should be above 100psi, and with in 10% of each other. water could be getting in thru a head gasket or exhaust gasket. hopefully thats all. if it's the head gasket it will show on the compression guage.
 
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Rbsgfd578

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Re: 1985 Johnson

I hope its not the head gaskets as there both not that old at all..On the exahust gasket how hard is it to change.Can the little guy with some mechanical knowledge be able to do it?
 
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Rbsgfd578

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Re: 1985 Johnson

Also how can the head gaskets get hurt if there not that old.My motor hasnt run hot or anything.Matter of fact I did a decarb not long ago and it has been running better than ever.
 
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ezeke

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Re: 1985 Johnson

The heads need to be re-torqued after break-in when new gaskets are installed.

Exhaust gaskets are easy to replace if the cover bolts come out OK.
 
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F_R

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Re: 1985 Johnson

The exhaust cover mentioned is the one in the V between the cylinder heads. The gaskets could be leaking, or there may be a corrosion problem with the baffle plate or even the cylinder block, not uncommon especially if you are running in salt water. A leak may squirt water into the cylinder through the exhaust ports.
 
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Rbsgfd578

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Re: 1985 Johnson

Ok quick update.Pulled the plugs outta my motor last night.Didnt have any yellowish or white froth on them.They were wet but wiped them with my finger and what came off was pure black and smelled like gas.
Why would my plugs still be wet after not being on the water for over a week?
 
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Rbsgfd578

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Re: 1985 Johnson

No mine pistons dont look like that...Thank goodness.
I looked through the plug holes with a flashlight lastnight and the had a I guess a copper,gold, color..
I hope thats Ok..
 
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