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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16213
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have a 2005 90 hp and the no oil light and alarm come on

Customer Question

I have a 2005 90 hp Johnson and the no oil light and alarm come on even though have full tank of oil. If I turn engine off and restart it doesn't come on, but after a while it does. Can you advise with these symptoms
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

Hi Linda, my name is Jason.

Can I get the actual model number of the engine please.

Customer: replied 1 year ago.
J90PLSOA serial number 05111908
Expert:  Jason replied 1 year ago.

Got it. The problem is going to be one of a couple of different things. How technical/deep of an explaination would you like as to the potential issues?

Customer: replied 1 year ago.
Well would like to know what could be wrong, is it an air bubble, is it the sensor or is it the pump
Expert:  Jason replied 1 year ago.

Good morning and sorry for the delay. We all do this on the side, out of our houses. When you had replied back last night I was out for the evening.

On this engine the fuel pump is also the oil pump. The pump serves 2 functions, it draws fuel from the fuel tank, and also draws oil from the oil tank, and then it mixes the fuel and oil inside of the pump before sending it out to the carburetors.

When the no oil warning comes on, it can mean a couple of things

1. There is a hose that connects the fuel pump to the engine block. This is called a pulser hose. If that hose is loose, torn, or compromised, the pump will not cycle correctly, and will not draw enough oil from the oil tank

2. There is a fuel line between the fuel pump and fuel tank. When the engine is running, the fuel line is always under a vacuum (the pump "sucks" fuel up from the tank). If there is any kind of air/vacuum leak on the fuel line, the pump will draw air in through that leak. This will again cause the pump not to cycle correctly, and not draw enough oil from the tank.

3. There is an oil line between the pump and oil tank. If the line has collapsed internally or is pinched, that will cause a lack of oil to the pump

4. In the oil tank itself is a strainer type filter, if that is clogged up that will cause the a lack of oil to the pump as well.

5. Lastly, if the pump is bad it will not draw enough oil from the oil tank.

What we do in the shop is first verify that the pulser hose is good, after that we inspect the fuel line for vacuum leaks. If that looks good we pull the oil tank and dump it out, and see if there is trash in the bottom of the oil tank. And we also make sure that we can blow through the oil line. The pumps are fairly reliable, and 9 times out of 10 the problem is in 1 through 4. But if nothing stands out at the end of going through all of the hoes and the oil tank, then at that point we would replace the pump. Does that all make sense?

Expert:  Jason replied 1 year ago.

I think that should do it. But I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you

Expert:  Jason replied 1 year ago.

Hi , it looks like you read my answer and logged off without leaving a rating or a reply back. I do want to make sure I answer your question on the issue completely, and I think that I have. If you do have a further question on the issue please feel free to reply back. If not, the website has charged you to speak with me but they will not credit me for helping you out until you put through a rating for me. Please let me know if you are having trouble when trying to put through a rating.

Thanks again and happy boating!