Exhaust plate leaks

[Josh S.]

The motor is a 1990 Evinrude XP 150. The problem is fouling of the plugs of the #2 and #5 cylinder with water/oil. The local marine mechanic is stating that the cause of this is leaking exhaust plate gaskets. Is this a valid reason for this? The mechanic thinks that a full rebuild/replacement of the powerhead is in order since he can hear a light knock, not sure I cant hear anything out of the ordinary. Obviously something is wrong, but before I kill my budget and do this, Id like to do my own diagnostic and figure out whats wrong. Any help would be appreciated. Thanks Josh

 

[F_R]

Re: Exhaust plate leaks

Absolutely. Exhaust cover leaks rank right up there near the top of the list of powerhead killers. Overheating is one cause of it, and salt water corrosion is another. It is a must-fix situation. Maybe even too late if you are running it in salt water.

 

[R.Johnson]

Re: Exhaust plate leaks

If you are pulling water into those cylinders', it must be corrected. A exhaust cover leak can let water into the cylinders, but do a compression ckeck first before you go to far..

 

[Josh S.]

Re: Exhaust plate leaks

How would I tell if its the exhaust plates and not something else? Obviously want to get this taken care of as soon as possible, but on the other hand don't want to get carried away either (spending money where it doesnt need to be spent). It is a freshwater boat, and winter is here so have plenty of time.

 

[Solittle]

Re: Exhaust plate leaks

Do a compression check as R.J. suggested.

 

[R.Johnson]

Re: Exhaust plate leaks

Where you have a water leak on both cylinder banks' makes me lean toward a exhaust cover, but you can't rule out the head gaskets either. I would start with a compression test before I went any where.