Bleed lines and plug fouling

[aussiejake]

I have a 2006 Mercury EFI 150 2 stroke that runs richer on the Port bank of plugs.
There are bleed lines that remove the fuel from the reeds and send the excess fuel to the upper and lower crank bearings.
Then the excess fuel from this is fed from the lower crankcase to the Port cylinders.

Now I removed the bleed line coming out of the lower crankcase going to the port cyliders and after a short run the plugs cleaned up and matched the Starboard bank perfectly.

The question is what problems can happen by removing these lines?
Do they lubricate or is it just to burn off the excess fuel?
If it is ok to remove were can I plumb it so the excess doesnt go into the water? Maybe back into the fuel tank?

cheers

 

[CharlieB]

Re: Bleed lines and plug fouling

Half of the fittings have a one-way check valve in them, they MUST be clean and functioning for the system to work correctly. A small hypodermic syringe with alcohol is helpful in testing and cleaning these fittings and valves.

You need the factory service manual to check the routing of the hoses to ensure they are correct.

One of the 'sticky' posts at the top of the forum has link(s) to service manuals, check it out. The manual will show the correct routing and testing of the recirc valves which MUST BE operating or the motor will continue to have the symptoms you currently have.

 

[aussiejake]

Re: Bleed lines and plug fouling

http://1manual.com/Mercury%20manuals/Service%20Manual%20PDFs/TwoStroke/883728/4a.pdf

Thanks for the reply Charlie, Page 14 has the bleed system layout. (Look at outlet 8 in the top drawing)

The bleed system and check valves are in good condition but just wondered if it could be removed from the cylinder input and sent back to the tank rather than adding more fuel to the port cylinders. Obviously I would leave the reed bleed system in place.

Maybe the cylinder inlets lubricate the centre crank bearings?
Or they are just used to burn off the excess fuel.

cheers

 

[Faztbullet]

Re: Bleed lines and plug fouling

The only time it would be rich is at a idle as the bleed system is pretty much empty of fuel above 2000 rom. If your talking about the fittings closer to crankcase half those lube the center main bearings and really not enough raw fuel passing thru these to foul a plug and if it was it would affect all cylinders as mains is not sealed. I would swap the stator leads on switchboxes and see if problem follows as my guess you have a weak stator output at low speed that why a bank is affected....

 

[aussiejake]

Re: Bleed lines and plug fouling

Thanks Faztbullet, that answered my question perfectly.

cheers.