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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3936
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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We have a 2007 Mercury optimax 115 running rough, poor idel,

Customer Question

We have a 2007 Mercury optimax 115 running rough, poor idel, lack of power,cuts off after a minute or so. We replaced spark plugs, fuel water separator filter. We also drained the water out of the water separator line. Can you give us advice on what else could've wrong?
JA: 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. Is there anything else important you think the Marine Mechanic should know?
Customer: There is old gas in tank from over the winter with no stabilizer
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Marine Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
Please respond. We are fixing boat now. If you can not, please send us a refund. It didn't say it was going to take up to 24 hours until after we paid.!!
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you.

In order to properly locate the issue with the engine, it is going to take several tests. You are going to need a spark tester and a pressure gauge that can read over 120 PSI.

The first place that you are going to need to test is the test valve on the rear of the VST. Hook up the gauge, then turn the engine key to ON. Watch the gauige and note the pressure. It needs toi read 25 PSI when the pump is running. If it does not, that pump is locked up, and will need to possibly need to be freed or even replaced. Let me know what you get on that.