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Water in cylinder 2 - Evinrude 70HP 1979

C

Cyprella

New member
Hi guys, I have a Evinrude 2 stroke 1979 70hp.

I was running the motor for around 10 mins on a high idle and then it slowly started to die off.
When it died of it sort of 'seized' in place and it wouldn't turn over. I removed the plugs and found cylinder 2's plug to be in half... After some direct 2 stroke oil it freed up. I then did a compression test and it was 100% as before (80,80,80). I then cranked it over to remove the oil and whatever was left in the cylinder.

I then reconnected it with a new plug and it fired up however I noticed that water is coming out of the back of the motor near the head cover. I turned it off and tried cranking without plugs in and found that water is coming out of cylinder 2. It does run, but baddly. I have heard two different responses on what I should focus on. Either head gasket or exhaust. If it is exhaust it's not worth fixing if its head its doable.

I will pull the head and see if the gasket is blown but wouldn't that show a decreased compression? Especially on cylinder 2?

What are your thoughts and where should I start (or if I even should)


EDIT - I presume this was caused by a poor 2 stroke mix or over heating (water pump/ thermostat just replaced though).
 
Compression of 80 PSI is way to low on this motor.-----Should show about 130+ PSI.-----Perhaps try another gauge.-----Yes the head will be warped in my opinion..----They all are after years of temperature cycling.------Remove the cylinder head for inspection.-----At an actual compression of 80 PSI you might need to do a complete overhaul or look for another motor.-------It be hard to find a new motor as simple / reliable as that 79 model was.
 
Ditto on Racerone's statement of the compression numbers.... For all to read exactly 80 psi is strange... loose head?

Most likely entry points of water on that model would be... Head Gasket, Warped Head, Exhaust Baffle Inner Plate and/or gaskets...... could also have a failed powerhead to adapter plate gasket.

However, the cylinder head area and that inner baffle plate are the most suspect.
 
joereeves said:
Ditto on Racerone's statement of the compression numbers.... For all to read exactly 80 psi is strange... loose head?

Most likely entry points of water on that model would be... Head Gasket, Warped Head, Exhaust Baffle Inner Plate and/or gaskets...... could also have a failed powerhead to adapter plate gasket.

However, the cylinder head area and that inner baffle plate are the most suspect.
Click to expand...



This is exactly what it looks like. (https://www.youtube.com/watch?v=POChNBcVci4) Will take the head off tomorrow, and buy a new (1988 Johnson 50hp) motor (with compression 130lbs). Are the Exhaust Baffle and Inner Plate hard thing to service? I assume they require a teardown. I would like to at least get it up and running again.

I have some hope as all the cylinders have even, although not high compression and it does still run. Could recoup maybe $300-$400 once if it runs again. I want to think its the head gasket leaking cooling fluid from the inner gallery. Is there any way to differentiate or tell if its the head or the exhaust plate leak?

 
Cyprella said:
This is exactly what it looks like. (https://www.youtube.com/watch?v=POChNBcVci4) Will take the head off tomorrow, and buy a new (1988 Johnson 50hp) motor (with compression 130lbs).
Click to expand...
What size boat is this engine pushing? Usually a boat with an engine at much lower HP than the max rated for the hull results in a very unhappy owner. If you can get the 70HP repaired that will be your best option..assuming it's close to your hull rating.

The 50HP were pretty good engines but so are the 3-cylinder 70's. I had one on a 15' tri-hull and it pushed the boat well and we could run all day on pretty much just a single 6-gallon tank of fuel.
 
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