evinrude dramas

[dish]

this is my first post so here is my story.
I am a commercial fisherman and i just purchased a little 18 foot cat as a
mackeral dory. twin 90 model 40hp evinrudes. first trip 100 miles flawless.
second trip got to destination fine,had a fish,had a snooze.next morning power down 1 cylinder each motor.Limped home 5 nots,40 mile,painfull...
cleaned carbys,new filters,cleaned out tanks.next trip 10 mile power down ,limped home again.took off flywheel,melted charge coil both moters.
changed both stator assemblys,ignition coils,spark plugs,leeds.
tested motors,bang,bang,bang.checked stators,1 long screw in stator assembly retarding timing.pulled head off and guess what? pitted piston head,scored cylinder.could not believe it.
here is the question? Is one minor score on cylinder need bore or can be still used with new piston,rings or go fishn,un bolt motors and row home.
p.s starbord motor low compression both cylinders,new rings maybe?

 

[tashasdaddy]

Re: evinrude dramas

your are depending on them, do it right, and quit rowing.

 

[jay_merrill]

Re: evinrude dramas

Are you going offshore with this boat? If so, how far?

 

[dish]

Re: evinrude dramas

Thanks for replying. I do go off shore,depending on the fish i an targeting
some times 20 mile sometimes 80 mile.If the cylinder has minor score and i
dont get it honed or bored will this just mean low compression in that
cylinder or will it cause further damage.The score is not raised just slight
scratch.the cylinder head is pitted bad as is the piston.Ring must have
caught port and snapped off.Also can you take cylinder block off without
having to remove whole powerhead.

 

[jay_merrill]

Re: evinrude dramas

If you can feel the groove in the cylinder wall with your finger, you probably need to bore it. I have to wonder, however, how it is that both of these motors ended up with massive ignition system failures and broken rings. Unless you have strong capabilities in outboard engine repair, I would let the folks at your local OMC/BRP dealer take a look at them. You are going way too far offshore to fool around with motor that might, or might not, be fixed properly.

As for running an 18 foot boat 80 miles offshore, I hope you will take the following statement as nothing more than fraternal (as in the fraternity of boaters) concern. I really think you are gambling with your life and I strongly recommend that you stop doing it. The simple fact of the matter, is that the weather could very easily change faster than you could get even close to a safe harbor. All it would take is for you to rely on one bad forecast, and you could find yourself many miles offshore, fighting for your life.

 

[dish]

Re: evinrude dramas

Thanks for your concern Jay.Where i fish is the east coast of Australia around the southern great barrier reef.There are lots of little islands you can hide behind if the weather comes away and a bigger mother ship.
As for the ignition problems who knows?The previous owner knew something i didnt i guess.
I just want a couple of years out of them before i whack 2 four bangers on
it or etecs.The evinrudes only have 500 hours which isnt many,i would do
that in 6 months,so there should be a bit more life in those babys yet.
By the time i rebuild them they will be as good as new,if i bother.

 

[jay_merrill]

Re: evinrude dramas

Ah ... I see ... quite a bit different. I thought you meant you were going 80 miles out into open ocean. With islands to duck into, things are quite a bit different.

I wonder what the previous owner knew about these motors also. Having two engines break rings and have a "meltdown" of the ignition systems at the same time is highly unusual. On the cylinder side of things, it makes me wonder if he overheated the engines somehow, or forgot to provide adequate lube.

At any rate, I would say that you are going to need to tear both these engines down to repair them.

 

[dish]

Re: evinrude dramas

Looks like it Jay.
pulled down port motor today,top cylinder perfect,rings look a bit loose,is there ment to be any play or not?
Bottom piston shot,ring destruction.Cylinder fine except for that tiny score.
Cylinder head looks like the moon.I think i did that when i tried tuning it
when the timing was stuck.
Starboard motor just down on compression although each cylinder reads the same.Should i just strip it,have a good look and change piston and rings or just use it with three quarter power?

 

[jay_merrill]

Re: evinrude dramas

What are the compression values on the "good" engine? If they are not too low, and the cylinders are within 10% of each other, the engine may be serviceable.

 

[dish]

Re: evinrude dramas

the good engine is 75psi top cylinder and 90 the other.
Think i will pull it down anyway and have a look.On closer inspection
with the cylinder head off there were about ten dimples on the piston
head closes to the exaust port.Think it is on the way out?
I can get pretty cheap piston and rings so i think i will change both.Cant hurt.
Also the center main crank bearing,i know it should split in two but the bearing cover looks like it was split by hand.Is this what they do after it is
mechined.Just not a perfect cut more like an educated hit with a hammer.....

 

[jay_merrill]

Re: evinrude dramas

I'm not sure about the crankshaft bearings but at 75/90 psi, you have too much differential. Sounds like that motor needs a rebuild too.

It also sounds like the previous owner sold you a boat that he had been "beating to death." I think he owes you a little more than a pint or two!