Over-pressurized Upper Oil Reservoir - breaks cap

[howardjltx]

I have a 1997 Bayliner Jazz - 175hp XR2 Sportjet boat. The main oil tank is pressurized by air from the crankcase through a "check valve". This pressure pushes the oil from the main tank up to the upper reservoir. The cap started breaking from the system being over-pressurized. The boat is running normally (i.e. I run the boat by temporally connecting to the crankcase until the reservoir is full) <br />I have checked and cleaned all the hoses between the Main tank and reservoir. I cannot determine the problem. 1.) Any Suggestions? 2.) Is the crankcase "check valve" strictly a one-way valve or does it act as a pressure regulator or is there a pressure regulator in the oil system? 3.)Could the problem be associated with the "Bleed" system (manual shows hose routing with (7) check valves but gives no operational explanation)?

 

[dingbat]

Re: Over-pressurized Upper Oil Reservoir - breaks cap

The "check valve' is actually a relief valve and they do good bad from time to time. On the other hand, those caps are prone to cracking even without an over pressure condition. I guess the thing to do is replace both and your troubles should be gone.

 

[howardjltx]

Re: Over-pressurized Upper Oil Reservoir - breaks cap

THANKS for the info...<br />The pressure broke a brand new cap. The check valve usually is just a one way valve, but it may be spring regulated. The problem is there are at least eight different chech valves around the front of the engine (carburator side) and I was wondering if one went bad could this cause overpressure in the crankcase - I would not want to go to the expense to replace all eight - I may try taking a pressure reading at each check valve while the motor is running to see if one valve is clogged.....

 

[gss036]

Re: Over-pressurized Upper Oil Reservoir - breaks cap

I have had 2 caps break on my 200, but since the last time, I just tighten it enough to make contact and just a hair more, if it too loose it will simply let oil run out the threads. Is the external tank bloating (over pressurized?)<br />I know this is not much help but is a common problem as stated before.

 

[dingbat]

Re: Over-pressurized Upper Oil Reservoir - breaks cap

I would imagine that all those check valves at the carbs are for the injection system and have nothing to do with the oiling system. <br />On the oil side there is a one way valve in the block where the hose to the large oil tank is attached to prevent allow pressure to only flow in one direction. There is also a 2 psi relief valve connected to a tee in the oil line at the small reservoir which is vented to atmosphere. A second 2 psi valve located in the line between oil injection pump and the fuel pump to prevent the flow of fuel from entering the oil injection system. The only valve that would cause the problem you are experiencing is the one that is vented to atmosphere at the small reservoir