1978 85hp Evinrude problems

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wetplug

Cadet
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Jul 27, 2010
Messages
6
I have a 1978 85hp Evinrude outboard that i am having problems with. This is what it is doing: It starts hard, and doesn't run at full power. When i take the plugs out, one plug is wet and the other three are dry. I have checked spark and have spark on all plugs. I have taken the carbs apart and cleaned them. The first time after i took the carbs apart and cleaned them and cleaned the wet plug then took the boat out i had lots more power for a minute or two and then the motor just bogged down again and the power never came back. Any ideas and also what would cause just one plug to be wet?
 
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Al-53

Chief Petty Officer
Joined
Jul 17, 2008
Messages
491
Re: 1978 85hp Evinrude problems

Ok you took the carbs apart and cleaned them....did you put a new carb kit in....did you wire the orfices out to get any junk out...also have you changed your fuel lines....you said after you cleaned it ran good..then went bad..your fuel lines may be breaking down with the ethanol gas....and clogging the carbs again.....or you did not get all the junk out of the carbs jets....

the top dogs here will get you going...just some suggestions from me is all....

Al
 
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wetplug

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Jul 27, 2010
Messages
6
Re: 1978 85hp Evinrude problems

I did wire them out, even though the carbs were actually spotless to the eye. Their wasn't any gunk in them that i could see. I'm just wondering about the one wet plug if this is maybe the issue or what would cause it.
 
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GerClaire612

Seaman Apprentice
Joined
Apr 18, 2010
Messages
43
Re: 1978 85hp Evinrude problems

i had the same problem with my boat. And like the guy said, buy a carb kit, change your fuel lines and clean the screen in your fuel pump and put a new fuel filter on your fuel line. A fuel pump kit could not hurt either. And every bit of it is faily cheep. Thats what fixed mine.
 
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autohead18

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Jul 25, 2010
Messages
12
Re: 1978 85hp Evinrude problems

head gasket remove head not water cover just head inpect the damage these motors do this all the time do not run engine this could be as bad as runing the motor while it is submurged very bad for power head 2 rings seal the piton ports water runs around these and thay fail puting water beeds on plug and damadgeing the motor change both before runing STOP sorry thought he was stating wet as in water on plug if you got only 3 cylinder firing make sure you have spark on all coils if you do wet plug could be very easy fix change plug check THAT WET plug for spark
 
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ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 1978 85hp Evinrude problems

Thed dry plugs are probably from not getting fuel, which means that the cylinders are not getting oil either.

Be sure that the high speed jets are spotless; there are four of them in the bottoms of the float bowls, behind the drainplugs.
 
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Sixmark

Master Chief Petty Officer
Joined
Jul 11, 2010
Messages
890
Re: 1978 85hp Evinrude problems

autohead18 said:
most def a head gasket remove head not water cover just head inpect the damage these motors do this all the time do not run engine this could be as bad as runing the motor while it is submurged very bad for power head 2 rings seal the piton ports water runs around these and thay fail puting water beeds on plug and damadgeing the motor change both before runing
Click to expand...

It's a bit premature to be telling someone that it is definately a head gasket failure. I have seen several motors over the last 25 years that had a wet/dry combination of cylinders that didn't require head gasket replacement. Many times all it requires is a good carb cleaning and tune-up. A wet cylinder can be as simple as a weak/bad plug or plug wire, or as serious as an internal engine problem, but you don't know unless you have all of the information at hand.
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1978 85hp Evinrude problems

You may only be running on 3 cylinders. Possible the wet plug is not firing. I'd double check the spark on that plugwire with an inductive timing light when the engine is in gear, idling at the dock. Weak ignition components have a tendency to fail when the engine warms up to normal operating temperatures.
 
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wetplug

Cadet
Joined
Jul 27, 2010
Messages
6
Re: 1978 85hp Evinrude problems

Have put in a carb kit and thoroughly sprayed/ cleaned out the jets and their is still no difference. Is their any way to test the power block or the coils?
 
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Sixmark

Master Chief Petty Officer
Joined
Jul 11, 2010
Messages
890
Re: 1978 85hp Evinrude problems

Did you check the spark as recommended?

If you didn't then I suggest you do so, if you find a weak or nonexistent spark then try swapping coils from one of the good cylinders, if the problem follows the coil then you have isolated your problem, if it doesn't then come back and let us know.
 
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