2008 Mercury 90 EFI
Moderators: Redneck_Randy, badmoonrising, lakerunner
-
- Posts: 7
- Joined: Wed Jun 22, 2016 12:37 pm
2008 Mercury 90 EFI
I have recently purchased a 2008 Mercury outboard 90 HP EFI (4 stroke) that had sat for several years. It first cranked and ran without any problems. However, after getting it out it seems to stall out idling witnin 5 minutes or less. I have run a full tank of 100% gas with seafoam in it. At times it looses power with a WOT and other times it runs awesome at WOT. But going back to idle it always stalls out. I can take the filter off the high pressure side and let the fuel pump prime (no bulb) it again it will be ready to go again. When you first crank it and let it idle it never stalls out until after running it. I have put new fuel filters on it as well.
Anyone have this problem or ideas?
Thanks!
Anyone have this problem or ideas?
Thanks!
Re: 2008 Mercury 90 EFI
Had a similar problem. Bought a boat that had a newer motor that sat for several years. The seller spent like $1,500 dollars to get the boat ready for sell which included basic motor tune up along with replacement of gas tank and all external fuels lines. The boat ran great first trip out. Soon got to the point it would not idle and cough a bit under throttle. Finally, it would not start at all except with starting fluid. The problem was the fuel lines inside the motor were original, and though not exposed to the elements, also chemically broke down from long term exposure to fuel that likely had MTBE in it. The carbs were loaded with little chunks of rubber. Cleaned the carbs and replaced the lines and that boat ran like a champ until I sold it. One possibility to look into.
'bob
'bob
- kryptonite
- Posts: 488
- Joined: Fri Mar 04, 2011 7:32 pm
- Location: Otter Lake (S. Central IL)
Re: 2008 Mercury 90 EFI
If you have a portable gas tank, try running it from it to eliminate any tank issues. If it runs good sometimes it seems it would be something in the delivery system.
2008 22' Tahoe Vista Elite Merc 75hp 4 stroke
Re: 2008 Mercury 90 EFI
I have a 2009 90 Optimax 2 stroke that broke down on me 4 times in 4 yrs---after 1st time rplcd fuel line replaced fuel pump grommet? and ran additives with every fillup. Finally idiot dealer after I TALKED TO HDQTRS in Fond du Lac(we are on first name basis now) and found out it was a rubber fitting in fuel pump(have 2 fuel pumps I think) that there was a bulletin on it and a fix. Whooda thunkit?
Knock on wood it still runs good so maybe have your fuel pumps checked--the starving prob with fuel may indicate bad fuel pump. Good luck.
Knock on wood it still runs good so maybe have your fuel pumps checked--the starving prob with fuel may indicate bad fuel pump. Good luck.
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS
-
- Posts: 7
- Joined: Wed Jun 22, 2016 12:37 pm
Re: 2008 Mercury 90 EFI
Ok I hooked a external tank up to it and seems to run better but still stalling out just not as quick. However, after running it for several hours now you cannot hear the fuel pump engage and it will not crank. I also get 6 beeps from the switch now. So bad fuel pump? or lift pump?
Re: 2008 Mercury 90 EFI
I had the same issue with my 90 merc 4 stroke. Merc dealer replaced the internal fuel float with the upgrade system. Runs like a new one again
Re: 2008 Mercury 90 EFI
Hello.
I had similar issues with my 2007 Merc... It was the fuel pump. After fixing that, runs like a CHAMP!! Good luck...
Sincerely,
Rich
I had similar issues with my 2007 Merc... It was the fuel pump. After fixing that, runs like a CHAMP!! Good luck...
Sincerely,
Rich
Rich and Annemarie Bias
2007 20' Princecraft Vantage 20L
2007 Merc 75 4 Stroke
2006 Honda Pilot
2007 20' Princecraft Vantage 20L
2007 Merc 75 4 Stroke
2006 Honda Pilot
-
- Posts: 7
- Joined: Wed Jun 22, 2016 12:37 pm
Re: 2008 Mercury 90 EFI
I replaced the fuel pump and fuel float (Mercury dealer advise that). Runs great now just expensive. Thanks for all the help!
Re: 2008 Mercury 90 EFI
Which fuel pump resolved this?
2008 Sun Tracker Party Barge 21' 2 Log NV performance Package, 90HP 4 stroke Mercury. 37MPH avg. on GPS.
- FLOUNDERPOUNDER225
- Posts: 314
- Joined: Thu Jul 16, 2015 7:19 am
Re: 2008 Mercury 90 EFI
Here is the problem, this one was from ethanol fuel that had sat for a long time, gathered water and corroded everything in the VST (Vapor Separator Tank) that's where the pmp and float are located.
- Attachments
-
- vst pump.jpg (234.98 KiB) Viewed 2632 times
-
- vst mercury.jpg (12.22 KiB) Viewed 2632 times
Pensacola FL
2015 Berkshire 231 RFC
Yamaha F-150
2015 Berkshire 231 RFC
Yamaha F-150