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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 14176
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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My 2005 Mercury 4-stroke outboard has a tendency to do the

Customer Question

My 2005 Mercury 4-stroke outboard has a tendency to do the following:
At launching, it starts normally but after a couple minutes it dies. This happens even when I increase the throttle. It won't restart until I let it sit for about ten minutes. I realize the following can't happen with fuel injection but it acts like it's flooded or vapor locked. It will restart after the wait. If I leave it in neutral an give it more throttle it usually responds to higher RPMs. After operating at higher speed neutral for a few seconds I can go back to idle speed and put it in gear. This problem can repeat itself again later after usage at normal operating conditions.
Submitted: 7 months ago.
Category: Boat
Expert:  Jason replied 7 months ago.

Hi Tom, my name is ***** ***** I will be helping you today.

Flooding and Vapor lock are both things that can and do happen with EFI engines. This wouldn't be a vapor lock issue, but flooding would fit the issue, and it would happen if the fuel pressure regulator was bad and fuel pressure was to high on the engine. It can also happen if the injectors are leaking down. Do you have a fuel pressure gauge to check fuel pressure?

Customer: replied 7 months ago.
Expert:  Jason replied 7 months ago.

Okay, no problem. Did you have any further questions for me on the issue?

Customer: replied 7 months ago.
OK, no problem" ? That's $29 worth of advice ? If I get a pressure gauge do I get a follow-up ?
That is the only possibility ?
Expert:  Jason replied 7 months ago.

I'll answer any question you have on the engine. But if you don't have the tools required to do any testing there is nothing I can do about that. Hi fuel pressure would fit the symptoms. But other things would cause it as well, such as a bad sensor. Checking fuel pressure would be step 1. If that is actually within spec, hooking it up to a scan tool is step two. Being a fuel injected engine there is very little a DIY person can do on these engines. Did you want to get your hands on a fuel pressure gauge and get back to me, or what would you like to do?

Customer: replied 7 months ago.
Even if I had a pressure gauge I would have to terminate this communication to go test it, then how would I get back in contact with you ? I live 100 miles from the nearest outboard mechanic but that's looking like the only option for testing with a "test tool" unless they are available at a place like Pep Boys. Is that a possibility ?
Expert:  Jason replied 7 months ago.

To get back here you would simply log back into the website. You can use a standard automotive fuel pressure gauge on the engine. So if pep boys sells them then that would be fine.

Customer: replied 7 months ago.
What I meant was, do places like Pep Boys have a "scan tool"? Is this the same as an engine analyzer ?
Expert:  Jason replied 7 months ago.

No the scan tool is Marine specific, and a car one would not work. The cheapest one on the market runs 400 bucks, and it is very basic in function. (and you really have to know what you are doing in order to use one effectively)

Customer: replied 7 months ago.
Thanks. That's it for now/
Expert:  Jason replied 7 months ago.

You are very welcome. Let me know how you make out on the fuel pressure check.

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