Oil Injection Pump Test - hot motor

[wcmaness]

I have a 1985 Mercury Black Max XR2 150 HP with oil injection. I suspect my oil pump is failing, but don't know how to test it. My upper reservoir is full. I disconnected the hose feeding the fuel line from the oil pump, and turned the engine over several times, but didn't see much oil. actually, it appeared to be only drips from what was sitting in the hose. Should that come out in a greater volume, or what volume - I just don't know. After that, I removed the pump & observed the pump key/shaft on the motor turning, so at least that shaft is not the problem. My water pump. thermostats and hoses are all new, and water runs through, but the engine still gets hot. That's why I suspect the oil pump. Long story short - how do I test the oild pump?

 

[Chris1956]

Re: Oil Injection Pump Test - hot motor

Get yourself a Merc Servie Manual. There is a pump output test within it.

BTW- if the motor is running hot, it is not too likely it is an oil problem. It is more likely a water circulation problem

 

[wcmaness]

Re: Oil Injection Pump Test - hot motor

I have the manual, and find no testing procedures for the oil pump. I would normally agree that heat is a water cooling issue. However, the water circulation is excellent, and the block heats up really fast. My warning buzzer is non functional.

 

[Chris1956]

Re: Oil Injection Pump Test - hot motor

I am surprized there is no oil pump output test. I think my Clymer has such a test for the Merc Motors. I know my OMC manual has one for the johnnys...

Did you check the poppit valve?

 

[wcmaness]

Re: Oil Injection Pump Test - hot motor

What & where is the poppit valve?

 

[Chris1956]

Re: Oil Injection Pump Test - hot motor

The poppit valve pressures the water jacket. It is located on the lower starboard side of the motor. There should be a hose connected next to it.

 

[wcmaness]

Re: Oil Injection Pump Test - hot motor

Do I have to remove the lower unit to check it? I don't see it in my manual?

 

[wcmaness]

Re: Oil Injection Pump Test - hot motor

By the way - I really appreciate your help & attention on this.

 

[Chris1956]

Re: Oil Injection Pump Test - hot motor

Look on the Crowleymarine.com web site. They have the expoded parts diaghrams for your motor. The poppit is held on by two bolts, and you should be able to get to it w/o disassembling anything. Be a bit gentle so you do not break the bolts.

 

[wcmaness]

Re: Oil Injection Pump Test - hot motor

Turned out to be a bad impeller installation/problem. All better now with a new one. Thanks.

 

[j_martin]

Re: Oil Injection Pump Test - hot motor

Them big mercs are fussy on water pump condition. I just replaced an impeller that looked fine except for a little "age" cracking and a definite set to the blades. Didn't even look worn much. There's a world of difference in the water pressure and cooling.

The housing will distort if you look at it cockeyed, and the base plate will wear enough to lose seal with a bit of sand.


John