Rebuilding 1998 Optimax 135HP

[wkwarrior]

Hello there,

My 98' 135HP Mercury Optimax develop a knock and here are the compression reading before tear down.

<TABLE style="WIDTH: 48pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=64 border=0 x:str><COLGROUP><COL style="WIDTH: 48pt" width=64><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; WIDTH: 48pt; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right width=64 height=17 x:num>120</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right height=17 x:num>125</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right height=17 x:num>105</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right height=17 x:num>105</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right height=17 x:num>107</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-LEFT-COLOR: #ece9d8; BORDER-BOTTOM-COLOR: #ece9d8; BORDER-TOP-COLOR: #ece9d8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #ece9d8" align=right height=17 x:num>45</TD></TR></TBODY></TABLE>

Upon close inspection, it looks like the ring pin on #6 let go and did lots of damage. This would explain the low reading of 45 psi.

1. Wrist/rod bearing are in good shape but i found play on some of the wrist pin to piston cleareance. You can feel a pretty good pay pushing and pulling on it. What would cause this on a few pistons?

2. I can see scoring on #4 and #6 piston. What is the cause of the scoring on these piston? overheat or lack of lubrication? This engine did not get the check valve upgrade in the oil line. Could this be the cause of both failures?

3. What is the general consensus on replacing rod bearing if they look good?

4. Are the bearings and seals from Promarine any good?

Thanks for the feedback.

Ed

[Capt.Insane-o]

On a 98 I would order a reman powerhead with a one year waranty to boot.