1965 Johnson 9.5HP -water in lower cylinder

[Fergy35]

Hello all. I have used the search function and read till my eyes hurt, but I did not see quite what I was looking for.

I have a 1965 9.5 HP Johnson that is a model #MQ-11C. The motor did sit for a few years before I got it. Anyway, I put it on the back of the boat, and started it in a barrel of water. It did start, not willingly, but it did start. Did not idle real well, but I figured I could re-clean and adjust the carb later - I wanted to try it on the water first. On the lake the first several pulls felt normal. Then the pulls got harder and did not sound right. One more pull and it's locked up.

Back home - pull the plugs and the bottom cylinder is full of water. I pulled several time to clear the water and sprayed some oil in there. I borrowed a compression gauge and I am getting a reading of 100 on the bottom and only 75 on the top. Repeated the test 3 times to be sure and get the same readings.

I don't have a huge budget for the boat (or I would have a newer motor anyway), so I don't want to start randomly replacing parts. Does it sound like I should start with the head gasket? And could someone be so kind as to let me know what the torque spec and sequence is.

 

[ezeke]

Re: 1965 Johnson 9.5HP -water in lower cylinder

You most likely have a blown head gasket caused by overheating.

Remove the cylinder head and replace only with a new gasket.

Keep the cylinder well oiled until you complete the repair.

You should replace the water pump impeller and check the thermostat.

96-120 inch pounds.

 

[F_R]

Re: 1965 Johnson 9.5HP -water in lower cylinder

Hello all. I have used the search function and read till my eyes hurt, but I did not see quite what I was looking for.

I have a 1965 9.5 HP Johnson that is a model #MQ-11C. The motor did sit for a few years before I got it. Anyway, I put it on the back of the boat, and started it in a barrel of water. It did start, not willingly, but it did start. Did not idle real well, but I figured I could re-clean and adjust the carb later - I wanted to try it on the water first. On the lake the first several pulls felt normal. Then the pulls got harder and did not sound right. One more pull and it's locked up.

Back home - pull the plugs and the bottom cylinder is full of water. I pulled several time to clear the water and sprayed some oil in there. I borrowed a compression gauge and I am getting a reading of 100 on the bottom and only 75 on the top. Repeated the test 3 times to be sure and get the same readings.

I don't have a huge budget for the boat (or I would have a newer motor anyway), so I don't want to start randomly replacing parts. Does it sound like I should start with the head gasket? And could someone be so kind as to let me know what the torque spec and sequence is.

Wow, to get so much water in the cylinder that it hydro-locks is unusual to say the least. There would have to be a MAJOR leak somewhere. Normally, I would look at the head gasket first, but with the amount of water that is getting in and 100lbs of compression, I sort of doubt that is the cause. I suspect a hole is eaten through somewhere between the cooling system and crankcase. Sorry, I can't be more specific.

Head gasket torque is 96-120 inch pounds, starting in the center and working outward in a spirol pattern. Tighten to 1/2 spec first, then go over them again at full spec.

 

[Fergy35]

Re: 1965 Johnson 9.5HP -water in lower cylinder

Thank you both, very much. I guess it's time to tear into it and see whats in there. I think I'll order that head gasket and impeller first though, so they are on hand when I start.

Ezeke, thank you for the diagram. I appreciate it.

 

[Fergy35]

Re: 1965 Johnson 9.5HP -water in lower cylinder

The blown head gasket was definitely the problem. I am now looking at a little over 70psi on both cylinders and no water in them.

While I was in there I went ahead and replaced the points and condensers (looks like someone replaced the coils already, they are definitely newer). I now have good compression readings and great spark at both plugs.

Now I think I should look at rebuilding that carb, but that will be a different thread.

Thanks guys.

 

[ezeke]

Re: 1965 Johnson 9.5HP -water in lower cylinder

If you have not already done so, you should re-torque the cylinder head bolts now that you have run the motor.

When you do the carburetor, use the OEM kit so that you get a new float. The floats are made of cork coated in shellac and shellac disolves in alcohol, so they need to be replaced more often than we would like.

 

[Fergy35]

Re: 1965 Johnson 9.5HP -water in lower cylinder

ezeke, That you, for the tips. I will re-torque the bolts when I get home. Where is the best place to get the OEM carb kit?

 

[ezeke]

Re: 1965 Johnson 9.5HP -water in lower cylinder

Any BRP/Evinrude authorized dealer/parts department: http://dealerlocator.evinrude.com/EN/?Rnd=1172157085156

Part #382,048. List price is around $26.00 US.

 

[Fergy35]

Re: 1965 Johnson 9.5HP -water in lower cylinder

Never mind, I just found a post where you guided someone else to ishopmarine.com, maxrules.com, marineengine.com or sea-way.com. Thanks again.