Rich Bank

[aussiejake]

What would cause the Port cylinders to run richer than the Starboard cylinders on a Mercury 2006 EFI 150hp 2 stroke.

Ive replaced the digitial temp sender in the head and checked all earths etc.

Any ideas would be great. Im thinking the ECM.

cheers

 

[jerryjerry05]

Re: Rich Bank

Not sure why,but how do you know it's running richer??
Remember,there are no dumb questions.
Well maybe there are but I'd still like to know???

 

[aussiejake]

Re: Rich Bank

Cylinders 2, 4 & 6 spark plugs are black and wet on the porcelain and cylinders 1, 3 & 5 come out paper bag color. This is the same every time.

 

[jerryjerry05]

Re: Rich Bank

http://www.mercurymarine.com/contact-us-online
Top of the page is a Contact Us link.
Look there it's for Mercury Service.
Follow the directions,you need the serial# to send in a question.
They have helped me and come in handy.J

 

[Faztbullet]

Re: Rich Bank

It might be the ECU but more a likely a electrical problem. The injectors are fired in pairs so if #1cyl pulse width is off so would #2cyl. I would swap the stator leads from switchboxes and see if problem follows as it may have a weak output. If that did not change anything swap position of the boxes and retest. If problem still exists you could have the injectors acting up but it would be odd to have them all on same bank.
Ignition system failure (switch box, stator, trigger,
etc.) can cause fuel delivery problems. Injectors are
triggered in pairs by one, three, five primary circuits
(inner switch box).
No. 1 Primary Triggers No. 3 & 4 Injectors
No. 3 Primary Triggers No. 5 & 6 Injectors
No. 5 Primary Triggers No. 1 & 2 Injectors
Failure in one or more of these primary circuits will
cause no spark and no fuel to respective cylinders

 

[aussiejake]

Re: Rich Bank

Thanks for the replies.
The motor is running well just wanted to get it a bit better.
The motor is a late model EFI, so no switch boxes etc. Has a Crank position sensor and coils.
I was looking at the ECM or TPS. But I think the TPS would make all the cylinders rich.
Coils and leads have been swapped over.
The plugs will run the same at 4500 plus rpm but the Port bank will richen up at lower cruise rpm around 3500.
I know this as I have done an engine cut off at higher rpm.

I might just be too fussy.

cheers.

 

[Faztbullet]

Re: Rich Bank

It a 2.5 model, that has the "triple nickel " style ECM and it could be a problem with it or a injector/s. You need a DDT to check it or have a dealer hook it up and test injectors. Also a defective t-stat would make that side run cooler and have incomplete combustion...

 

[aussiejake]

Re: Rich Bank

Thanks for the reply Faztbullet.
I have put in new thermostats and Poppet and monitor temps through smartcraft. The DDT had no faults and the injector and coil tests were all 100%.
Idles at 64 Celcius, once over 1200 rpm it drops to 38 Celcius.
It really is an odd one.
I even tried crossing over the the connections between the starboard and port digital temp senders, but it still ran the same.
It doesnt foul the plugs they just come out black on 2, 4 & 6 cylinders. It has to be a temp issue or ECU.
Dont know how to increase the Port head temps while running though.

 

[aussiejake]

Re: Rich Bank

Is water meant to leak past the thermostats?
I did a check and when running water through the remote flusher with the motor cold and not running I get water somehow getting past the thermostats on both heads. Thermostats are fully closed, the rubber gasket must not seal tightly?
From 3lbs pressure upwards water leaks past. (The pressure shows on the mechanical water pressure gauge)

 

[aussieflash]

Re: Rich Bank

I think Fazt is on to something.I found both my Tstats to be seized 1/2 open,so i was running cold at mid to WOT.That might explain why 2 of my plugs where blacker than the others.Take them out and test them.Might just need a clean + new gaskets.

 

[aussiejake]

Re: Rich Bank

Thanks Flash.
It seems that could be the problem. They are definately not stuck open but do allow a lot of water to bypass them when cold.
I made up 2 gaskets last night to go between the thermostat housing and the head which pushed the thermostats harder into the housing.
No water now leaks past at any pressure, I even started it on the hose and water only came out the tube once temps hit 64 C and opened the thermostats.
Water used to come out as soon as the motor was started.

I will do a water test this weekend, after Clipsal

 

[aussieflash]

Re: Rich Bank

You going to the race???Are you from Adelaide??

 

[aussiejake]

Re: Rich Bank

Yes & yes. Going on Saturday