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I am looking for details on a oil pressure switch for a 2001…

Hi, I am looking...

Hi, I am looking for details on a oil pressure switch for a 2001 mercruiser 4.3

Mechanic's Assistant: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.

So, I bought the boat second hand, and realised that the fuel pump is constantly running, even when the ignition is on but not turning over After a bit of research I discovered that there should be an oil pressure switch which only energises the fuel pump when it detects oil pressure

Mechanic's Assistant: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Marine Mechanic should know?

The oil pressure switch had been removed and the purple and purple / yellow wire were just tied together. I bought a replacement switch, but I think I am missing a fitting

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Answered in 39 minutes by:
3/24/2018
Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 17,853
Experience: Degree in Marine Technology. Gas and diesel marine mechanic.
Verified

Good morning, my name is ***** ***** am I speaking with? I read what you wrote. Mercruiser engines are actually cataloged by serial number, and not by year. Do you happen to have that number handy?

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Customer reply replied 3 months ago
Hi Jason, I'm Cyril. The engine serial number is ***** thanks

Hi Cyril, okay got it. Give me a few minutes to pull the correct books and make copies.

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O​kay got it. Now what exactly were you looking for in terms of information? Did you need a wiring diagram, as well as an explanation of how it all works? Also, you mentioned the word fitting so i'm not sure what you mean by that.

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Customer reply replied 3 months ago
at the moment it was only the oil pressure sender that was present, see image named pressure1.jpg. Should the pressure switch be attached to the sender and then both screw into the block, above the oil filter housing?

C​lick this link for a picture, this is what it should look like when it's all put together. http://cdn.shopify.com/s/files/1/0748/6631/products/IMG_5536_1024x1024.JPG?v=1425628510

All of those fittings are just brass plumbing/weatherhead style fittings. You can get them at your local hardware store. Does that make sense.

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Customer reply replied 3 months ago
Would you have the mercruiser part numbers, in case I can't easily source them?.In terms of wiring details, for the pressure sender:
Terminal 1 goes to the negative terminal on the battery, and terminal 2 is connected to the light blue wire which goes to the gauge?The pressure switch - terminal 1 purple terminal 2 purple /yellow (or vice versa).Is that correct? thanks

Sure, on the part numbers, click this link for a diagram. you need numbers 1 and 3, the part numbers are listed on this page - http://www.mercruiserparts.com/bam/subassembly/31480/2694/60

On the wiring. Click this link for a picture - https://imgur.com/a/oih4J

In the picture, #6 is the fuel pump, #5 is the oil pressure switch, #7 is the starter solenoid. The fuel pump on this engine operates under 2 conditions. The first condition is when the key is turned to start, and the engine is actively cranking over. Under this condition, the starter solenoid sends power to the fuel pump on a purple with a yellow stripe wire. Once the engine starts up, and you let go of the key, the starter solenoid will stop applying power to this wire. At the same time, once the engine is running, there will be oil pressure. Once there is oil pressure, the oil pressure switch will send power over to that same purple/yellow wire. On the oil pressure switch there are 2 wires. Think of them as in and out. Your switch has 2 green wires on it. One of those green wires will connect to a purple wire. The purple wire will have power whenever the key switch is in the START or RUN positions. The other green wire will go over to the purple/yellow, for the fuel pump. The oil pressure switch is a simple on/off switch, so it's not polarity sensitive. Does that all make sense. 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 or more specific 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.

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Thank you
Jason

Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 17,853
Experience: Degree in Marine Technology. Gas and diesel marine mechanic.
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Customer reply replied 3 months ago
Perfect, that's what I need. Thanks

You are very welcome. Thanks again and happy boating! -Jason

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