Servicing a blown head gasket.. questions

[Dallas214Stars]

So after very troubling day at the lake and
a compression test cylinders two and three dropping to 60 and 30 psi I’ve decided to change the head gasket on my Chrysler 115 hp. I’ve been reading that the bolts need to be torqued correctly… And I’m not sure how much they need to be torqued, does anyone know the process of this and how much? Also I’m reading the reason the head gasket could’ve blown could’ve been 1- that it’s old and just failed, 2- that impellers bad so I’m going to check the water pump and replace it if necessary, 3- thermostat went bad. I’m trying to figure out what kind of thermostat does this motor take, and where can I get a new one? Any other ideas of what I might need to check while replacing the gasket would be great. Thanks for all the help

 

[The Force power]

First I would find out why the drop in psi, Cylinders/walls scored/ cracked rings ? OR blown Head-gasket?

-Inspect the head to see if its warped (lay flat on piece of glass & check with feeler-gauge
-Thermostat can be bench-tested (in boiling water) will not cause gasket failure
- torque bolts to 21 foot-lbs criss cross. START with inside bolts and AT 15 ft.lbs with 5lbs intervals to 21 lbs

 

[Dallas214Stars]

So the head gasket is fine... cylinder 3 has some scoring that was the 15psi and 2 looks ok that was as 60psi. I’ll attach some pictures. I’m guessing the issue might be on the other side of the piston that I can’t see? Haven’t ever taken one of these off so I’m a bit new as to what I’m looking for that could be causing it.

 

[Dallas214Stars]

[No message]

 

[racerone]

Sounds like the motor needs to come apart for rebuilding.-----Scored cylinders only get worse with more running time.----After looking at the pictures I say it ran hot.-----Has to come apart !!------Need to find what went wrong or it will go ----" boom " ---Again.

 

[Dallas214Stars]

Sounds like the motor needs to come apart for rebuilding.-----Scored cylinders only get worse with more running time.----After looking at the pictures I say it ran hot.-----Has to come apart !!------Need to find what went wrong or it will go ----" boom " ---Again.

What are you looking at in these pictures to tell that it ran hot? Also how are u able to tell that it needs to be pulled apart? Asking because I’m trying to learn the signs of this issue coming on so like u said it doesn’t happen again. If the head gasket is good what to you presume caused the low compression in cylinders in 2 & 3? What is it that is causing these cylinders to be scored like that?

 

[racerone]

Ran hot / no oil !!------I am going to be blunt here.----I have looked at more than 1 damaged outboard motor.----But perhaps wait for an answer you want to hear.----Sorry , your motor needs to come apart !

 

[Dallas214Stars]

Ran hot / no oil !!------I am going to be blunt here.----I have looked at more than 1 damaged outboard motor.----But perhaps wait for an answer you want to hear.----Sorry , your motor needs to come apart !

I don’t need to hear an answer I want to hear I just want to figure out what needs to be done to fix it... obviously it needs repair but I’m trying to get an idea of what is a good spot to start — it just seems like you seem to have some sort of idea what’s the issue is. If all you say is it needs to be repaired I knew that soon as it quit on the lake lol

 

[racerone]

The pistons / rings are damaged and leaking compression !------Rings are now stuck in grooves and can not move to seal compression.------The motor needs to come apart.------You will see what I mean then !

 

[racerone]

Remove the bypass covers on cylinders with low compression.-----Inspect pistons / rings there.------Post pictures of what you see there.-----That will tell the story

 

[Dallas214Stars]

Remove the bypass covers on cylinders with low compression.-----Inspect pistons / rings there.------Post pictures of what you see there.-----That will tell the story

Is this the bypass cover?

 

[Dallas214Stars]

Took it off... can’t see much with the bypass off

 

[Dallas214Stars]

[No message]

 

[racerone]

Rotate the flywheel.-----Remove covers on cylinders with low compression.----Post pictures of piston ring area.

 

[Dallas214Stars]

Rotate the flywheel.-----Remove covers on cylinders with low compression.----Post pictures of piston ring area.

Unless it’s somewhere I can’t see or missing I’m not seeing any rings on the pistons

 

[Dallas214Stars]

[No message]

 

[Nordin]

That side is the intake side.
The damage is at the exhaust side.
That is the side where it gets hot (really hot).
You do not need to pull of the exhaust cover plate, it is just a lost of time.
Some or most of the screws at exhaust cover plate will snap and you have more things to deal with.
Do as racerone says, pull of the block and disassemble it.
99% the rings are stuck in the piston groves and the piston walls are scored at the bad cylinders.
There are some things that cause these problems.
Bad/less lube in the fuel, lean setting of the air/fuel mixture screw at the carb, bad cooling (shot impeller and or clogged water jackets in the block and head).

 

[jerryjerry05]

When the covers are off, rotate the flywheel and the rings should move into the area where
it can be seen.

The reasons for the failure: carbs adjusted wrong, the fuel recirc system clogged, timing off, using cheap oil TCW2 and many more.
The fuel recirc system: just in front of the port covers are 2 dog bone shaped covers.
Under these are reeds and screens that fail and clog.The old oil TCW2 caused the rings to carbon and seize.

 

[racerone]

Some wish to argue.------Pistons that run normal have some black carbon on them.-----When they are grey as pictured here they were HOT------Post pictures of the pistons when they are out of the motor ! ------End of the story.

 

[The Force power]

At this point......I would start shopping for "good used" Power-head.

I don't want to sound pessimistic but by the time you get the block bored/new pistons /rings / gasket-kit & necessary tools to do it; You will have spend the money for it. (unless you want the challenge & have the time)

BTW

raceone / Jerryjerry / Nordin (and others) are Experts in this field; Don't question it just except it