[rpf]

Hi,I have put a deposit on a 1987 boat with a 70hp VRO Evinrude. The mechanic informed me yesterday that the motor has the following compression readings:145 psi145 psi125 psiI see from previous messages that it is more important for each cylinder to be within 5-10% of one another. The Mechanic indicated that the cylinder wall had some scoring which is causing the 125-psi. He read that there is a bulletin on this motor with regards to this cylinder not being cold properly and for one hour of labour and a 15 dollar part that can be rectified and should prevent any further loss in compression and scoring in this cylinder. Should I be concerned as this is 16% of the other two and could this recommended fix prevent further damage? Or should I move on and look at other boatsÂ…Any help on this would be much appreciated.Cheers Ross

[OBJ]

Welcome Ross!I do not know of any bulletin about the lower cylinder running cold and a fix for the problem. There are a couple out that do address the heat sensor and relocating the telltale elbow. What part is the mechanic going to replace?My opinion on the engine is this....the damage is done and will not get better. If anything, it will get worse over time. Did the mechanic actually pull the head to look at the cylinders? Are the scores really scores or scuff marks from running the cylinder to lean? The three cylinder loopers are good engines for sure....but buying one with a known problem....well...if nothing else, I would try and get the price down on the engine.

[rpf]

Hi OBJ,Thanks for responding so quick.A couple of thingsÂ…I had the compression in reverse order (shows you how much I know) about motors. The compression from top to bottom is.125145145The mechanic said it is some sort of plug that he is putting in based on the bulletin. You are correct the damage is from running hot on the top. This fix will properly cool it.The Mechanic did not take the cylinder head off but confirmed that it is scored and not scuffed.Does this change your opinion?Sorry to miss lead you with the first information. Cheers, Ross

[R.Johnson]

As OBJ pointed out, it sounds like he will relocate the tell-tale elbow. I don't know how you would tell a score from a scuff with out removing the head. In my experience, a scored or scuffed cylinder will show a piston that will look even worse, once removed. It will not stop, and it won't get better. The only thing I know off that will restore compression is a wrench. I have had very little success with anything in a can.

[Wakeboarder Tom]

I agree with RJ above - the mechanic can do b****r all to fix this. Get a reduction in the price of the boat if you can. The only way of solving the reduction in compression is a rebore.You will find that the engine will not idle properly if the compression levels are different - we had the same problem on our 70. The cause was a packed up/intermittent VRO which starved oil to the fuel so be very careful about buying this. THe cause of your scoring may not be a simple overheating problem. The problem your mechanic is trying to solve is that occasionally this model engine can get an air lock in the waterjacket at the top of the block. Moving the telltale outlet to the top of the flat metal plate on the side of the block stops this from happening, although it is more likely to be something a bit more serious.It may be cheaper in the long run to lose the deposit and find another boat??!

[rpf]

Hi RJ & Wakeboarder Tom,Sorry for the delay between messages but I was in Europe on business and never seem to have enough time....Thanks for all the advice. I am moving on to the next situation and look forward to sound advice such as yours in my future endevours.Thanks again,Cheers, Ross