Tips and advice for repairing outboard head gasket

[Samu_el]

Hello everyone, I’m a new young boater looking for advice on fixing an outboard motor. I’m also new to this site and am looking forward to being here! I’ve studied internal combustion engines for a while but don’t know much about outboards and have little experience working on engines. I was given by my uncle a 1980’s Sea King 15 Horse by Chrysler 2 stroke that he and my dad used to use before it gave out on them more than twenty something years ago. My dad told me that their fuel mixture wasn’t on point and my uncle said that it overheated when they last used it. The top cylinder has no compression which I discovered a gasket failure. I removed and inspected the impeller after studying some YouTube videos. It seems all I need are a new impeller and head gasket. Does the head need to be filed and machined? I greatly appreciate your time!

 

[Nordin]

Check if there are any score in the cylinder walls?
If, can you catch it with your finger nails?
If no score put a new head gasket and impeller in.
Torque the gasket to proper value in a circular patter starting from the middle left bolt and in CW.
Do it in three steps of the torque values.
If you can catch score with your nails then you maybe can hone the walls and go from there.
Anyhow you have to change head gasket and impeller.

 

[racerone]

The head is warped.----They all are.----Refinish it with emery paper on a flat surface ( piece of glass ) before installing.

 

[Samu_el]

The inside of the cylinder with the broken gasket seemed smooth and fine to me. Do I need to take the motor to a shop to have the machining done to fix the warped head or is that a waste of money to have someone do it for me? My dad was saying that it would need to go to a shop.

 

[Nordin]

From the pics it do not look like it has overheat badly.
The power head is not light brown in color, which it normally would be if it has overheat bad.
I have never machined a head which has overheat.
You can flat it by sanding with fine water sanding paper.
Put the water sanding paper at a piece of glass plate and move it in a "8" pattern movement. Sand it so the surface will be flat and smooth.
If the warp is bad you will not fix it this way, but I have never seen a head that overheat so bad that this would not fix it.

 

[jerryjerry05]

Just put it on a piece of glass and see how big the gaps are?
Never saw one so bad it couldn't be used.

 

[racerone]

Best practice is to make sure the head is flat.----You want bolt torque to squeeze the gasket.----Not part of the torque to straighten the head !----But everyone works to a different standard too.

 

[Samu_el]

Hello again everyone! Hopefully I don’t wreak havoc by bumping this thread. I got the head to a shop for $25. I sanded the block myself, sanded and cleaned the water pump housing and replaced my impeller. I’ve learned so much about outboards these past couple of months! I my motor fires now, but it won’t spin low enough to idle. It dies after a few seconds unless I mess with the throttle. I also replaced my lower unit oil, probably never been replaced since 1980 new. My dad and I took apart the carburetor and did our best to clean everything up with an air compressor and carb cleaner twice. Is my carburetor bad or is there an adjustment I have overlooked? I tried adjusting the mixture screw and even removing it with little to no effect. I adjusted the throttle screw with only managed to keep the motor running under load but no idle. Thank you!