Evinrude 1983 60hp low compression

[DrDim]

I recently bought a boat with what I think is a 1983 Evinrude 60hp 2 cylinder engine (I made a different thread about the year on the engine before).
It idles fine but no real power during load so I did a compression test this evening, the top cylinder only got 50psi and the bottom got 150psi (seems a bit high?).
I tried putting some motor oil in the spark plug hole to see if the psi would raise, however no effect.

What could be wrong? What should be my next step? Head gasket? Junkyard? What happens if I continue running on one cylinder?
I'm hoping a new motor isn't the answer... any help is deeply appreciated.

 

[Bosunsmate]

I recently bought a boat with what I think is a 1983 Evinrude 60hp 2 cylinder engine (I made a different thread about the year on the engine before).
It idles fine but no real power during load so I did a compression test this evening, the top cylinder only got 50psi and the bottom got 150psi (seems a bit high?).
I tried putting some motor oil in the spark plug hole to see if the psi would raise, however no effect.

What could be wrong? What should be my next step? Head gasket? Junkyard? What happens if I continue running on one cylinder?
I'm hoping a new motor isn't the answer... any help is deeply appreciated.

Nope, a new motor is only very rarely the answer, these motors all have parts readily available and are mostly easy to work on especially if not a salt used motor.
Your first step is too remove the head. Take photos so you know how to reassemble. Remove the bigger head bolts on the rear and look at the cylinder walls for signs of scratches and inspect the head gasket for signs of failure.

After that id remove the water jacket which is the little area to the rear of the head and clean it and check the thermostat

 

[Bosunsmate]

Ive this engine and they are great.

 

[Stickler]

Oil in the cylinder is to verify worn rings,if no change,it likely isn't rings, or worn to the point where oil won't make a difference. I'd pull the head gasket and take a look inside, could also be worn/damaged intake or exhaust valves!

 

[racerone]

150 is the correct compression on one of these motors.

 

[DrDim]

Is it possible to do this expection while the boat is in the water. The problem is that I have it in a river and there's no place to pickup the boat along the river (except crane), so I would have to drive it for 6km on the river to a big lake where there are ramps. I'm guessing this is not very good for the cylinder with low psi.

 

[Stickler]

Forgot to mention scored cyl wall or carbon seized rings.

 

[Chinewalker]

Oil in the cylinder is to verify worn rings,if no change,it likely isn't rings, or worn to the point where oil won't make a difference. I'd pull the head gasket and take a look inside, could also be worn/damaged intake or exhaust valves!

It's a 2-stroke - no intake or exhaust valves to wear...

Do pull the head, though, and see what's going on. Can be done without pulling the boat. Might get lucky and have a blown head gasket, which can also be done in situ.

 

[Bosunsmate]

Is it possible to do this expection while the boat is in the water. The problem is that I have it in a river and there's no place to pickup the boat along the river (except crane), so I would have to drive it for 6km on the river to a big lake where there are ramps. I'm guessing this is not very good for the cylinder with low psi.

Doing this on the water would be the worst place unless you only have sea legs.
My motor has 105 and 95psi and goes like a bullet

 

[racerone]

Checked one of these motors a few weeks ago.-My gauge read 155 and 130.------I know my gauge reads accurately.

 

[Bosunsmate]

Checked one of these motors a few weeks ago.-My gauge read 155 and 130.------I know my gauge reads accurately.

My gauge reads accurately too, i just checked compression on my tractor at the weekend with it. All i can say with owning one of these and pushing a 14foot fibreglass with three adults and one child on board that with 105 and 95 psi she still goes good, straight up on to a plane and a good topspeed, (i dont have a tach or a speedo).
They are loopers.
If i could get her up to 150psi im sure id be tickled pink

 

[DrDim]

What should I look for? Do I just have to remove the bolts to check this? Is this the part that I probably need? http://www.skruvat.se/batdelar/Toppackning-Omc-40-60hk-P352443.aspx

 

[Bosunsmate]

Yes thats the head gasket you will need one of them, yes you will need to remove the bolts and also the ignition coils. Make a note of which wire goes where. i put tape on mine, you dont want the top coil being put back on the bottom. I think on mine i just unscrew them and pull them off to the side while i remove the head.

The outer water cover jacket is very cheao compared to the head gasket as it doesnt contain any metal fire rim

 

[Bosunsmate]

What you a looking for is scratches in the cylinders and or an area in the headgasket inner metal rim that looks like engine combustion or water has being seeping through it

 

[DrDim]

I forgot to mention that the spark plug on the bad cylinder was pretty clean ifr?n that masters? Would it be best to buy a new head gasket directly before removing the head? Also do I need anything more than just the head gasket to replace it?

 

[Bosunsmate]

Nope, take the head off first before ordering so you can inspect- in case its more than just that.
If your piston top is clean it might mean waters getting in

 

[bonz_d]

Compression on the ones I have or had.
1975 50hp Johnson 150 + 150
1983 60hp Johnson 148 + 150
1987 50hp Johnson 145 + 145

 

[DrDim]

No Title

I gave it a try today but I did only have a ordinary wrench and some bolts seems to need a bit of force and are in hard places. Also I'm actually not totaly sure if I removed the correct bolts (I'm really no mechanic guy). Could someone point me to if I removed the correct bolts in this picture (I have removed the coils

 

[Chinewalker]

No, you did not. You need to remove the larger ones around the outer edge of the head. There will be 10 in all. 1/2" head. The ones you removed hold on the water jacket cover.

 

[bonz_d]

Not to worry, no big deal. I do think you need to go to the local hardware store and buy a small set of socket wrenches and once you are finished you will need to go to an auto store that rents tools or borrow a torque wrench to tighten the head bolts. You can do this and we here are more than willing to lend assistance. Keep asking question when unsure and it will get done correctly.