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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10894
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I have a 1990 3 cyl 2 stroke 75hp engine. I have found a

Customer Question

I have a 1990 3 cyl 2 stroke 75hp engine. I have found a hose that is disconnected but I don;t know what it is for or where it connects to. One connection is at the bottom of power head or where the plugs go in and the lower unit starts. It is a clear soft rubber tubing and gas and oil seem to come out of it.
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.


Could I get the engine serial number please?

Can you post a pic of the hose you are referring to?

Is this hose on the port side of the motor? Are all the hoses connected to the oil pump?

Customer: replied 1 year ago.
Serial #0c260843 I don't have a pic at this time. And I am not sure about the oil pump connections. What I can say is that I visually inspected the entire engine and could not find a place that this tube would connect. I discovered it after I realized it was being squeezed by the engine cover. I then slowly pulled on it and it came out of the inside of the engine behind the oil reservoir without any resistance.
Expert:  Tan replied 1 year ago.

Without seeing where the hose was pulled from and the location is is hard to say where it exactly goes. The only hoses on the engine are fuel lines and oil lines.

The oil line runs from the bottom of the oil tank over to the oil pump. The fuel lines run from the engine connection in the motor pan to the fuel filter to the fuel pump then from fuel pump to the carburetors. So the only line I can think of that is go fuel and oil is either an oil line or a fuel line. So without seeing the hose it is really hard to say.

I wouldn't run the engine till we get this resolved. If it is an oil line you could burn up the engine if you try to run it. If it is fuel line the engine won't run.

Here is a link to upload a pic.

Customer: replied 1 year ago.
I won't have a pic till tomorrow. Do I have to start over or can I continue this conversation then? Also the engine does run however on the trip before I discover the tube, it would not go past 2400 rpm and was running as if it was only using 2 cylinders. No alarms going off just would not reach top speed nor rpms.
Expert:  Tan replied 1 year ago.

No you don't have to start over just post back as you have been.

Lets get the hose issue resolved first then we can move onto the engine run issue. You can check spark on all cylinders with a spark gap tester. The spark needs to jump a 7/16" gap. This will get this out of the way and give us an Idea if this is a spark or fuel related issue.

I will be here tomorrow.

Customer: replied 1 year ago.
Expert:  Tan replied 1 year ago.

Your welcome talk tomorrow.

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