1966 johnson 6hp oil return hose nipple

[danielvanalphen]

I've taken off the oil return hose on my 1966 johnson 6hp to see if any blockages are present. I can blow air through the top nipple with no resistance but the lower nipple is a different story. I cant get air to go through. Its getting fully blocked. Wondering if this is normal or how to fix
Thanks

 

[Crosbyman]

the oil gets pushed up the hose with crankcase pressure on the down stroke...it may have a check valve to prevent the oil (and air) from returning


have you tried sucking air out the bottom hose nipple to confirm the flow...OUT of the lower cranckase cavity ?

are you having a problem... use a clear hose and just see if the system is working properly. you should see some.. oil being pushed up the line. or try air blasting any crud out of the way


try rotating the piston to different travel position to see if your blown in air can escape

 

[oldboat1]

Carefully run a piece of weed whacker line through it to clean; follow by carb spray with plastic nozzle.

 

[racerone]

There is no check valve.-----But You can not blow into the bottom fitting.-----Fill the hose with oil and see if it drains down.-----Or start the motor and see if oil spits out.

 

[racerone]

edited

 

[danielvanalphen]

Carefully run a piece of weed whacker line through it to clean; follow by carb spray with plastic nozzle.

I've put copper wire in with carb cleaner and it goes in about an inch and then just completely hits a wall. Like wont go any futher

 

[Crosbyman]

don't fix a non-existing problem try post #4 and if it spits out the oil you are OK .

 

[F_R]

Your motor is normal.

 

[danielvanalphen]

Your motor is normal.

Say its not allowing oil to pass, do you know what would happen then? Would the main bearing that its oiling fail or?

 

[racerone]

It is an oil recirculation line !!-----I am replacing / installing a new crankshaft on one right now.-----There are drilled passage ways to this hose.----A 90 degree turn..-----No check valve.------Amazing design , these 6 HP motors.----Have a dozen myself.------Start this motor.-----If oil spits out than install new hose and go fishing.------There are likely other things that need more attention than this hose !

 

[F_R]

Even if no other obstructions or bends, anything stuck into the lower nipple would hit the crankshaft.
Without having an open one in front of me, I believe the upper nipple connects to the intake manifold, which applies a bit of vacuum to the hose, which sucks oil up from the lower bearing when the lower crankcase is pressurized. Some similar motors have a slot in the crankshaft which acts as a rotary valve and actually pumps oil to the top. I know the 7.5hp has the slot, not sure about the 6. Anyhoo, it is not plugged (never have seen one plugged in 24 years of daily experience in the dealer's shop)

Find something else to worry about.

 

[danielvanalphen]

Even if no other obstructions or bends, anything stuck into the lower nipple would hit the crankshaft.
Without having an open one in front of me, I believe the upper nipple connects to the intake manifold, which applies a bit of vacuum to the hose, which sucks oil up from the lower bearing when the lower crankcase is pressurized. Some similar motors have a slot in the crankshaft which acts as a rotary valve and actually pumps oil to the top. I know the 7.5hp has the slot, not sure about the 6. Anyhoo, it is not plugged (never have seen one plugged in 24 years of daily experience in the dealer's shop)

Find something else to worry about.

Ok thanks so much for the information, it's more the fact that I have the powerhead completed apart to replace old gaskets as I've done everything else on the motor and was just curious about the oiling system, thanks for the information

 

[danielvanalphen]

It is an oil recirculation line !!-----I am replacing / installing a new crankshaft on one right now.-----There are drilled passage ways to this hose.----A 90 degree turn..-----No check valve.------Amazing design , these 6 HP motors.----Have a dozen myself.------Start this motor.-----If oil spits out than install new hose and go fishing.------There are likely other things that need more attention than this hose !

Appreciate the detailed information, I have two 6hp 1977 and 1965, I've take the powerhead of the 1966 to paint and replace head gasket and other gaskets, I was just curious as the oil tube is the only part of the engine that I havent replaced or fixed but from what you've said I think it should be fine, thanks for the reply Appreciate it