Chris Dauth
New Member
This one has got me stumped !
First up a bit of history. This is a new boat to our marina, a 2005 Champion 925 with twin 5.0L TBI Mercs driving B1’s Raw water cooled, and it’s the owners first “big” boat. It was shipped 1000 miles up here by road. The owner did have a sea trial and “it seemed to go OK”. Past history is lacking.
We are a small boating community and between us have bought most of the Mercruiser tools, including a Rinda scan tool. A “real” Mercruiser dealer with techs are 500 miles away !
As I’m the “old man” of the marina, the manager asked me if I would “take a look” and see what is going on. Well, we started the port motor up, and it is rich, I mean heaps of black smoke and within about 30 seconds there was ¼ “ thick soot floating around the back of the boat !
My first pick was the ECT sensor (engine coolant temperature) which will tell the ECU (MEFI 3) the motor is cold and therefore give her more fuel. So I grabbed the scan tool and it showed the correct temp and we could see it change as the motor warmed up. It settled out at 155 F. Also, on the scan tool, there were no codes set and all other engine parameters were within spec., almost spot on per the Mercruiser manual # 24 which covers the 305 and 350 TBI & MPI.
Over the course of 2 days, we have changed all the sensors from the starboard engine (which runs perfectly) and the fuel filter. The IAC and the TP sensor have been changed as well, and there has been no change.
We pulled the two injectors and took them up the road to have them tested by the local fuel injection specialist. So, this is what we are up against, the specialist tells us, “never seen anything like them before in my life.” We picked them up next day, nothing wrong with them, no charge ! I’m wondering if anything was done ??
My thoughts are now, as the marine electronic fuel injection (MEFI) is open loop, no oxygen sensor, the extra fuel getting in is coming in thru the worn injectors or the wrong injectors. Our next move is to swap the injectors out of the good starboard motor. The only thing we haven’t checked is the 30psi fuel pressure. We have to make up a gauge to do that.
Anybody have this problem ??
Is there somthing I have missed ??
Oh for a 4 barrel carb.
First up a bit of history. This is a new boat to our marina, a 2005 Champion 925 with twin 5.0L TBI Mercs driving B1’s Raw water cooled, and it’s the owners first “big” boat. It was shipped 1000 miles up here by road. The owner did have a sea trial and “it seemed to go OK”. Past history is lacking.
We are a small boating community and between us have bought most of the Mercruiser tools, including a Rinda scan tool. A “real” Mercruiser dealer with techs are 500 miles away !
As I’m the “old man” of the marina, the manager asked me if I would “take a look” and see what is going on. Well, we started the port motor up, and it is rich, I mean heaps of black smoke and within about 30 seconds there was ¼ “ thick soot floating around the back of the boat !
My first pick was the ECT sensor (engine coolant temperature) which will tell the ECU (MEFI 3) the motor is cold and therefore give her more fuel. So I grabbed the scan tool and it showed the correct temp and we could see it change as the motor warmed up. It settled out at 155 F. Also, on the scan tool, there were no codes set and all other engine parameters were within spec., almost spot on per the Mercruiser manual # 24 which covers the 305 and 350 TBI & MPI.
Over the course of 2 days, we have changed all the sensors from the starboard engine (which runs perfectly) and the fuel filter. The IAC and the TP sensor have been changed as well, and there has been no change.
We pulled the two injectors and took them up the road to have them tested by the local fuel injection specialist. So, this is what we are up against, the specialist tells us, “never seen anything like them before in my life.” We picked them up next day, nothing wrong with them, no charge ! I’m wondering if anything was done ??
My thoughts are now, as the marine electronic fuel injection (MEFI) is open loop, no oxygen sensor, the extra fuel getting in is coming in thru the worn injectors or the wrong injectors. Our next move is to swap the injectors out of the good starboard motor. The only thing we haven’t checked is the 30psi fuel pressure. We have to make up a gauge to do that.
Anybody have this problem ??
Is there somthing I have missed ??
Oh for a 4 barrel carb.