Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 2003 Mercury 90hp 4 stroke fuel leak?

Posted by Mallard1100 on 04/04/20 - 6:12 PM
#1

Hi gents, I have a fuel leak on my 2003 90hp 4 stroke Merc that has me scratching my head here. Heres, the timeline of events and some details. The leak seems to be coming from the bottom carb fuel line ( of course hardest to see and get at). It runs down the line and drips right at that point.

In November 2019 the leak started. Came back to the boat a month later and run the engine on muffs for 20 mins. Zero leaks.

February 2020, take the boat out and run the engine for over an hour at different rpms. Zero leak.

March 2020, first trip on the water for stripers. Run the engine for 6 plus hours. Zero leak.

April 4th, 2020, take the boat back out and I have gas leaking again.

No performance issues at all. Motor runs great aside from this.

What gives!? Maybe something sticking in the carb or cracked fuel line? I attached some pictures of the carbs and the bottom carb fuel line where the fuel is running down (right below the intake manifold) It’s source seems to be where it connects into the carb. Could the fuel line have stretched at that point and start to leak or crack? I have also read a few things about these older grey merc fuel lines breaking down? These like are most certainly originals and at this point 17 years old.

https://postimg.cc/hhxd5rwG
https://i.postimg.cc/hhxd5rwG/89009-A...94-AA3.jpg

https://postimg.cc/bSQSSybn
https://i.postimg.cc/bSQSSybn/F5-C0-F...-A24-B.jpg

https://postimg.cc/m1xFrzcR
https://i.postimg.cc/m1xFrzcR/21-A32-...F355-C.jpg

[edit to fix links]

Edited by Phil T on 04/05/20 - 11:05 AM

Posted by Phil T on 04/05/20 - 11:06 AM
#2

I say replace all the lines and crimps with alcohol resistant fuel hose.

Posted by Mallard1100 on 04/05/20 - 2:56 PM
#3

Thanks. Pulled off the lower cowling. Sure as shit, line is cracked. I managed to get the line out but it was tricky. Is there a proper plier made to better install these fuel line clips? Any tips.

https://postimg.cc/kBSqCmpd
https://i.postimg.cc/kBSqCmpd/4389-B9...B8-E55.jpg

(Note - please use url link and not img)

Edited by Phil T on 04/06/20 - 6:13 AM

Posted by Phil T on 04/06/20 - 6:15 AM
#4

Try to come at it perpendicular with plyers if possible. Still a pita.

Posted by biggiefl on 04/07/20 - 8:16 AM
#5

I usually break them off and then use wire ties to install new.

Posted by Mallard1100 on 04/07/20 - 2:50 PM
#6

biggiefl wrote:
I usually break them off and then use wire ties to install new.

Thanks. I’m going to use the mercury zip ties made for fuel lines. The clips don’t seem to be worth the aggravation. I was over thinking it. Thanks gents.