Mariner 15hp 2 stroke fuel issues

[jeffstevens763@g]

bulbs perish any cracking? i had a bulb leak under the jubilee clip/fuel clip once, it had rubbed through not seen until stripped down,fuel connector O rings and dirt on the ball bearing. you could pump the line up with foot pump to pressure test. sometimes rubber when punctured only leaks one way thats why they turn dry suits inside out to test

[gocherhaz]

Small sign of "good news"

Took the fuel pipe off where it comes from the fuel filter and put a a direct hose with a small funnel of fresh fuel. I had someone hold the fuel up in the air and slowly pour fuel down the funnel. It ran this then leads my believe it is the hose or primer bulb or even fuel tank. Another thing is that my fuel was just shy of a year old, which doesn't help.
I have a new hose coming tomorrow a genuine one.
So let's see if it goes tomorrow.

Yet again thank you to everyone getting involved.

[gocherhaz]

Does someone want to explain how the fuel pump works? Thank you

[jeffstevens763@g]

How does a diaphragm fuel pump work?
It might also be considered the pump's bottom side (although this type of pump will work in any position). The fuel inlet (from the tank) is on the left. The impulse diaphragm (which is on the other side) moves out and in as the pressure in the impulse line goes low and high (relatively).9 Jan 2009
Diaphragm Fuel Pumps - OpenContent Curriculum - BSSD Wiki
wiki.bssd.org/index.php/Diaphragm_Fuel_Pumps
Search for: How does a diaphragm fuel pump work?


in short
just air pressure pulling the rubber diaphragm in and out causing a vacuum to pull the fuel through
or on four strokes works off the cam /crank whatever the design is pushing a plunger on the diaphragm doing the same thing

injected are different two pumps low & high pressure pumps

[gocherhaz]

Does someone want to explain how the fuel pump works? Thank you

[gocherhaz]

Changed the fuel line. Took the fuel pump off and looked at it in case of blockage. Everything seems fine. Still no luck! I have air coming from engine to the pump also.

[neil.mccrirrick]

Check your primer bulb if you can take it off. There will be an arrow on it indicating the direction of fuel flow. If you blow in it that way you will be able to blow through it. Try the other way and you shouldn't be able to. If you can the baffle in the bulb has gone. The fuel pump will not suck fuel if it keeps "falling back".

[gocherhaz]

Originally Posted by neil.mccrirrick

Check your primer bulb if you can take it off. There will be an arrow on it indicating the direction of fuel flow. If you blow in it that way you will be able to blow through it. Try the other way and you shouldn't be able to. If you can the baffle in the bulb has gone. The fuel pump will not suck fuel if it keeps "falling back".

Hi Neil. I have replaced the fuel like with primer bulb. Cheers

[Bigplumbs]

At the risk of teaching you to suck eggs. Did you make sure the arrow on the primer bulb is pointing to the engine in terms of flow.


I still think air is getting in somewhere. Did you try removing the fuel line carb side of the pump, switching off ignition and pulling the engine over to see if any fuel pumps out

[gocherhaz]

Originally Posted by Bigplumbs

At the risk of teaching you to suck eggs. Did you make sure the arrow on the primer bulb is pointing to the engine in terms of flow.


I still think air is getting in somewhere. Did you try removing the fuel line carb side of the pump, switching off ignition and pulling the engine over to see if any fuel pumps out

Would fuel come back out that way?

[gocherhaz]

Okay guys, So after everything I tried. I ordered a new one off eBay. It starts and runs great!
My outcome is this, I think that it being Ex RNLI and the fact they do modifications to the carbs, It has been allowing air in somewhere. I don't know where but it has. I have had that carb on and off at least 20 times.

Thanks for everyones help!

[Fenlander]

A new what?

[gocherhaz]

Originally Posted by Fenlander

A new what?

Sorry. A new carb

[Fenlander]

Ouch costwise I guess... but a good result.

[gocherhaz]

Originally Posted by Fenlander

Ouch costwise I guess... but a good result.

Wasn't too bad. cheaper than a new outboard

[Bigplumbs]

So air getting in well done