2.4l scoring?

[wanagofass]

A buddy of mine just pulled the starboard head off of his supposedly fresh/low hour 2.4l due a cyl being low on compression only to find all of the cylinders pretty serverly scored, he called a pretty knowledgeable outboard shop and they told him that was normal for these motors, what do you guys thing? Do 2.4s typically score worse/sooner than others? I'll take some pictures of it tomorrow.??

[wrechin2]

They are normal to have pits and stuff but not scoring. It usually takes a pretty sever blow to damage the crome. I see more out of round cylinders causing problems. A picture will help in determining if it is normal or not.

[ChrisCarsonMarine]

It takes hundreds of hours use to polish the original satin look of the chrome to a bumper chrome shine...they never score under normal use,it either overheated,under-oiled,or injested a mud-dobber nest,chris

[wanagofass]

merc 2.4l chrome bore
the worst cyl at 126 psi

[wanagofass]

http://tinypic.com/view.php?pic=qyzlmg&s=7
the worst cyl at 126 psi

[wanagofass]

http://tinypic.com/view.php?pic=s30zme&s=7
#4 @ 147 psi
http://tinypic.com/view.php?pic=4ucfbb&s=7
#5 @ 134 psi
http://tinypic.com/view.php?pic=vb5p1&s=7
#6 @ 150 psi

[wrechin2]

That is not normal. On the first pic you posted it looks like there is aluminum deposited just between the exhaust and transfer port. Looks like it may have overheated. They will usually discolor but not do what you have. Pictures sometimes make it look worse than it actually is. Here is a 200 I am tubing and you can see some discoloration but it is a slick as a glass. Hope this helps!

http://i53.tinypic.com/5035h3.jpg

[wanagofass]

Its actually not aluminuum deposits, its hard to tell in the pictures bbut the light areas are low as if the chrome was gouged off.

[wrechin2]

That is bad. Can you feel grooves where it light? It looks like aluminum transfer to me here in this picture.

http://i53.tinypic.com/xcngpk.jpg

[tlwjkw]

Looks like all 4 in those pictures are done!...........jmo

[wrechin2]

Looks like all 4 in those pictures are done!...........jmo

+1 The deck looks corroded badly also.

[tlwjkw]

BTW! Bobby wants a picture of your router/sunnen combination.........

[wanagofass]

That is bad. Can you feel grooves where it light? It looks like aluminum transfer to me here in this picture.

http://i53.tinypic.com/xcngpk.jpg
That is aluminum and you can definitely feel it but doesn't feel like it's uilt up with aluminum, more like it gouged down to the aluminum.

[wanagofass]

Looks like all 4 in those pictures are done!...........jmo
What's strange is that most of them are within 3-4 psi of the best cyl which is right where it should be 150psi with the heads it using.

[tlwjkw]

It is very strange that it was still doing anything at all. Don't think it was long for this world with what I'm seein' in those pictures. Might have been that way ta start. Just through in some new and/or different pistons, rings and sent it down tha road (to your buddy). Donno. Just a guess!.............

[wanagofass]

They told him when he bought the boat that this motor had only been run about five times since a complete rebuild, but didn't tell him about the scoring that they found after about one hour of breakin when he changed to the cut heads, he called an outboard shop and they told him these blocks were bad about scoring and he didn't know how but they held good compressionn some kinda way even after they scored. The thing runs like a top but inside looks like it's blown up.

[wrechin2]

BTW! Bobby wants a picture of your router/sunnen combination.........

I use a Sunnen AN815 HD ridgid hone and a 1/2 drill going through a 20 amp router controler. I can slow it down to get the crosshatches you see in the blocks I do for him.

[Jay Smith]

Ya using "dino" oil to break in at at least 40:1 ? That would be one that needs dial bored gauged and check the ring end gaps...

Jay