91 Force 150 - Possible Head Gasket???

[Jaxxyo]

Back before winter when I was winterizing the 91 Force 150 on my boat I noticed that the spark plug on #2 was clean and the others were black. These spark plugs were all replaced new several months before. So now that the lakes are starting to show signs of open water I wanted to tackle this issue before it becomes a bigger problem.

So today I did a compression test that came out as follows... Keep in mind this was a cold motor that had sat all winter. And it hasn't been decarbed yet and I have owned it 2 years. And I'm not sure of any previous maintenance on the motor.

#1 - 150
#2 - 125
#3 - 150
#4 - 150
#5 - 150

I then used a inline spark tester to verify all 5 cyclinders are indeed sparking. My question is based on this information do you think the head gasket is leaking water and steam cleaning the plug on #2. This is the conclusion I came to from all the searching I did. I'd appreciate any input you experts out there can give me as to what my next steps should be. By the way thanks for everybody that responds to these questions. Being a first time outboard owner and some what mechanically inclined, I've been able to perform all my own maintenance on this motor. With out everybodys help I'd have a lot less money in my pocket. I've attatched a picture of the plugs. The top one is #1 and the bottom is #5.

Thanks Again!

Jeff

 

[ddrieck]

Re: 91 Force 150 - Possible Head Gasket???

Maybe but it may also be your reeds are toast. Pull the top carb and look have look at the reed cage. Look more toward the bottom of the reed cage for any damaged reeds. The top carb feeds the top two cylinders and the lower reeds in that reed cage may be damaged and flushing the cylinder with raw un-burnt fuel. This will also give you a lower reading during the compression check.

While your in there you may also want to go through and refresh the carbs. I have the same outboard and it burnt the center piston due to running lean. Have a look at my project thread below to see the damage it will do.

 

[Jaxxyo]

Re: 91 Force 150 - Possible Head Gasket???

Thanks for the reply,

I pulled the top carb and didn't see or feel any damage to the reeds. I pulled out the reeds and they appear to be in perfect condition. I attatched pictures. So what's next? Time to pull the head off?

Thanks again.

Jeff