High Pressure Fuel Filter and Injector Removal 2007 Merc 115 EFI

[RedTail8]

Hi Folks, I've been struggling with an issue with my outboard that's been frustrating. Now the latest behavior has been getting up to about 4000 RPM with an extremely bogged down acceleration. Eventually the alarm will come on, 4 beeps, limp mode, more intermittent alarm then it will eventually just die.

I was reading in the operators manual tonight that the high pressure fuel filter should only be removed by a certified Merc tech with a special tool to relieve the pressure before changing I'm guessing. I didn't do that and just unclipped the two different filters and replaced them. Actually had accidentally put the low pressure filter in backwards. Later had realized it, bought a new filter and put it back in the correct way.

When I had these issues start I was reading a lot about clogged injectors being the issue so I took them out and flushed them with carburetor cleaner. I also hadn't relieved the pressure in the system so gas shot out a little from the rail and injectors when I was taking it apart. Later just put it all back together.

I have a couple of questions. First would taking it apart without relieving the pressure in the system cause any issues? And second now that I've put the injector system back together does the system need to be purged of air or anything like that? Maybe these items causing the problems I'm having with my motor?

I'm waiting for a couple of manuals to arrive but curious on this now that I read that about the high pressure fuel filter tonight. Based on how it's acting was thinking it was probably an issue with the fuel system somewhere too with maybe the fuel pump or something

Thanks for any help.

Marc

 

[Texasmark]

Ping Faztbullet or just type in a reply to your post saying "Bump". That will put it back at the top where its easier for him to see or send him a message.

 

[GA_Boater]

Relieving fuel pressure is a safety procedure so you don't spray gas in your eyes.

Any time you open the fuel injection system, relieve the pressure first. Put a rag or paper towel over the Schrader and depress the center pin. It goes pssst and the pressure is gone. If you don't bleed the pressure, the first break in the system will relieve the pressure. It's safer to do it with the Schrader. The special tool is a small screwdriver or a valve stem tool - Nothing special about it.

After the pressure is relieved with the Schrader valve, you can safely remove the high pressure filter. The fuel system is self purging. As you crank the motor over, the high pressure pump will push the fuel to and through the injectors as they open.

To clean the injectors takes a little more than just soaking or spraying with carb cleaner. Injectors are electrically activated needle valves. To clean them means actuating them as solvent is flushed through. That's a little hard to for a DIY'er, but not impossible.

Do you know what the 4 beep code means, by any chance?

 

[RedTail8]

When I flushed them I was actuating them at the same time. There's a YouTube of a guy that used larger to smaller pieces of marine shrink tube that attaches to a bottle of carb cleaner and the injector at the other end. Then a couple of lead wires to pulse the injector while also spraying the carb cleaner. I know it's not as good of a job as sending them in for ultrasonic cleaning and testing but I was also mainly looking for how well they sprayed if noticeably clogged possibly being my motors issue and none of them were. No flakes of anything seemed to come through them either. I also had back flushed them the same way.

I don't know what the four alarms mean. Someone in another forum posted a chart of different frequency of alarms and 4 wasn't on the chart. I'm tired of throwing parts at it so want the manuals to know how to troubleshoot and test specific parts - i.e. resistance through the sensors rather than just replacing them hoping the next part will fix it. It's pissing me off. Best time of the season for musky fishing and my boat is a rolling paperweight.