compression question..1994 evinrude 88hp

[papyson]

this motor was run extremely hot...to the point where it melted some insulation etc...last year the compression was checked...3 cylinders at about 100 and one about 95..today i checked the compression...it was 70 on all cylinders...same gauge as was used last year..the only difference was this year all the plugs was removed while checking...what i find strange is that all the cylinders read even..right around 70...any help appreciated...carl..

 

[joereeves]

Re: compression question..1994 evinrude 88

You mentioned nothing that was done after the overheating problem. Were the head bolts re-torqued after that extreme overheating scenario, head gaskets replaced, other bolts and screws tightened etc? If not, it would be a good idea to remove the heads, clean all sealing surfaces, install new gaskets, and torque the head bolts back to factory specifications. A 30 psi drop in compression isn't to be taken lightly.