Fuel Problem

genesis08 · #1 08-22-2009, 11:43 AM

Is there anybody on the site that has an Inline six on their boat?I used to have like an external fuel pump with a filter in it installed.it was Electric.I removed it but I think I should not have as I believe the engine is been a bit starved for fuel.To discribeb it,its about 5"tall,2" Diameter made of brass,inlet,outlet and 2 wires on it.

Thanks for the help,

Brian....

macojoe · #2 08-22-2009, 03:22 PM

Your motors fuel pump should be all you need.

genesis08 · #3 08-22-2009, 05:56 PM

Thanks Mac,

Problem is the engine will rev no problem when she is out of gear,but once you put the load on she is not getting up to full power.So I thought that was why there was an electric pump fitted which I had removed and as you said I did not think I needed it.Maybe I do.I think she is not getting enough fuel,,,,Brand new pump and brand new carb.Tha engine just seems starved...Any ideas?

Regards Brian

spareparts · #4 08-22-2009, 06:27 PM

use a portable outboard tank hooked to the mechanical pump on the engine to isolate the fual system. Then if it starts running bad, squeeze teh primer bulb to add fuel presure, if that fixes it, then check the fule screen on the fuel pump or replace teh pump. You could install a fuel pressure guage after teh pump and check the same thing, but it requires a special fitting, you could make one(inverted flare fitting with a t) or order one from mercury

genesis08 · #5 08-23-2009, 04:25 AM

Thanks Spareparts,Thats a good sugestion.I will try that the next day I get out.Weather here has been crapfor the last few weeks,Rain,Rain,Rain.I think I need to move back to the states.Anyway I am still trying to figure out why there was an electric pump fitted aswell to the boat when I got it?

Regards Brian

Hammerhead · #6 08-23-2009, 10:19 PM

I hava inline 6 w/o any external pump and it runs fine. It did duffer from a starvation issue but, went away when I got rid of the anti-siphon check valve. ( Those little steel balls in the fuel line inside the tanks ).

By all means,..check with others if t's OK to do that. Local boat mech said it was OK.

Hope it helps.

turbinedoctor · #7 08-25-2009, 01:03 AM

I have a Merc 90 inline 6 with out an external fuel pump, it ran fine for three years until the other day when it died on me. I was not related to not haveing an external fuel pump though.

Did yours run ok with the external pump?
Is you internal pump working ok?

Turbo