525 Vapor Lock

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06-17-2021 | 07:59 AM

#11

thirdchildhood

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Joined: Oct 2005

Posts: 5,825

Likes: 612

From: Clarkston, Michigan

The 525 is unique in that it has an electric fuel pump to pressurize the fuel system before starting; Then the mechanical pump takes over. That's why you have to turn the key on, wait for the pump to stop running and then start the engine. It also has a fuel cooler.

06-17-2021 | 12:17 PM

#12

imartin

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Joined: Jan 2005

Posts: 686

Likes: 18

From: Canyon Lake, TX

yep, its a sound you cant miss, and I never start the engine till several seconds after the electric fuel pump stops. Good point.

06-17-2021 | 03:50 PM

#13

Unlimited jd

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Joined: Jul 2009

Posts: 8,527

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From: Taunton Ma

Quote:

Originally Posted by thirdchildhood

this is completely incorrect. The mechanical pump pushes fuel to the electric and aids in priming. Just follow the fuel lines. First stop after the filter is the mechanical pump

06-18-2021 | 08:37 AM

#14

Cory H

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Joined: Feb 2012

Posts: 265

Likes: 16

From: Omaha, NE

I have vapor lock issues on one of my 1997 502MPI's with VST. Anyone know a way to "purge" the vapor quickly to get fuel back in the rail and get going without waiting 1.5hrs to cool down?

08-23-2021 | 08:39 AM

#15

Slalonde24

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Joined: Aug 2020

Posts: 24

Likes: 10

Quote:

Originally Posted by endeavour32

This weekend the port engine completely stopped running after getting warm and turning it off. 3 hours later, it still wouldn't fire up. Checked spark, and plugs were firing. So then I stated working my way through the fuel system, When I removed the water separator, the gasket didn't look right, so I replaced it. Went back to the helm, turned the key and once the fuel pressure reached 90 PSI, I turned the key and the engine fire up instantly. I then took the boat for a test run, to get the engine warm. An hour after turning it off, it fired up. The next day, same, no issues at all.

So, if anyone has a 525, and experiences this, change the water separator. You may be lucky and have it solve your problem.

Hey Mike, did you ever have this problem reoccur? Ive been experiencing this problem every now and then for about a month now. Fires up cold every time but after it sits for an hour or more she doesnt want to start for 5-10 minutes until I push the vapor out of the fuel system. Port motor still, Starboard motor fires right up every time.

08-23-2021 | 04:14 PM

#16

imartin

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Joined: Jan 2005

Posts: 686

Likes: 18

From: Canyon Lake, TX

I had a huge thread on myike issues, after changing almost everything, it was the fuel line from tank to mechanical fuel pump. Port was 100% blocked, srbd was 70.

08-23-2021 | 04:18 PM

#17

F-2 Speedy

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Joined: May 2012

Posts: 11,427

Likes: 3,953

From: Midwest & T-Rock

Quote:

Originally Posted by Cory H

I have vapor lock issues on one of my 1997 502MPI's with VST. Anyone know a way to "purge" the vapor quickly to get fuel back in the rail and get going without waiting 1.5hrs to cool down?

see if there is a shrader valve on the fuel rail towards the middle of the intake