60 hp powerhead tear down pics

[Disco44]

Cracked open my 93 60hp 2 stroke to investigate knocking and low compression in the top cylinder and found this, I would say that piston is toast!

The other 2 seem ok, any thoughts or input?

 

[merc850]

You might be able to rebore the cylinder .015 oversize and find a piston to fit; is this the knocking piston or is it one of the others?

 

[wrench 3]

That cylinder either overheated or wasn't getting enough oil. Being the top cylinder you tend to think more towards not enough water to cool it properly, but cover all your bases before running it again. A lean fuel mixture can cause a cylinder to overheat but the damage is usually more at the top edges of the piston.

 

[jimmbo]

The other two pistons and cylinders are free form scoring?

 

[Disco44]

You might be able to rebore the cylinder .015 oversize and find a piston to fit; is this the knocking piston or is it one of the others?

I'm taking to machine shop tomorrow, this was the knocking piston, top

 

[Disco44]

That cylinder either overheated or wasn't getting enough oil. Being the top cylinder you tend to think more towards not enough water to cool it properly, but cover all your bases before running it again. A lean fuel mixture can cause a cylinder to overheat but the damage is usually more at the top edges of the piston.

This was a no oil issue, the oil injection hose disintegrated and by the time I figured it out it was too late but yes already have new impeller.

 

[Disco44]

The other two pistons and cylinders are free form scoring?

Yes the other two seem to have no scoring at all, and everything else looks good to me but wanted post to see if I missed anything.

Ty for the input

 

[Faztbullet]

That motor does not have a oil injection hose/s...better look at the top carb real good.. Also have machine shop check that sleeve has not moved rearward..

 

[Disco44]

That motor does not have a oil injection hose/s...better look at the top carb real good.. Also have machine shop check that sleeve has not moved rearward..

Thanks for the reply Faztbullet, I might be using some wrong terminology.
My oil reservoir had a hose from the bottom to the oil injection pump, is that not correct?

 

[flyingscott]

edit

 

[GreedyMuffin]

I have a 60HP from 97 that got issues. Will tear it down sooner or later, and/or sell it in parts. The engine from 97 looks okay. Got it dirt cheap. 250 USD inlc. controll + speed and gear wire) full instrumental package, and it got a working trim/tilt. Everyting works fine except the possibility of a faulty piston.

 

[Disco44]

No Title

I'm about to take powerhead to machine shop and I assume all components need to be removed but cannot figure out how to remove this tan and blue wire by the middle plug? Any help?

 

[Faztbullet]

My oil reservoir had a hose from the bottom to the oil injection pump, is that not correct?

That supplys oil to pump and that feeds oil into fuel system, if that line failed all the cylinders would have received no oil not just one...

 

[Disco44]

Well took PH to machine shop and the guy said that he could bore the top (scored) cylinder but the others look good, he would measure the middle and bottom cylinders.
Is boring 1 a bad idea?

 

[Faztbullet]

Nope...

 

[Disco44]

Nope...

Roger that, thanks

 

[Disco44]

Picking up powerhead from machine shop today, tech said bottoms 2 cylinders checked out ok and bored the top cylinder .030. Going to be ordering parts and gaskets this weekend. Is there any parts or bearing etc...that is a must to replace while it's cracked open.

New piston
New rings, all 3 Pistons
Gasket set
Impeller
Thermostat

That's what's on list thus far,

Thanks for all the help!

 

[racerone]

You have to determine what caused the problem.---Fix that.------Or be prepared for the same failure again !

 

[Disco44]

You have to determine what caused the problem.---Fix that.------Or be prepared for the same failure again !

Yes, faulty warning alarm and busted oil red hose to oil pump!

 

[jimmbo]

Check that top carb very carefully for fuel level and/or dirt in the fuel circuits