240 EFI running rich AND low speed control actuator does not work HELP!

[SeptemberC]

330ish hours on engine
Compression on all cylinders is in 115-120 range.
Throttle Position sensor - replaced
Port & Starboard head temp sensors - replaced
mechanical fuel pump - rebuilt
Fuel/water seperator filter - replaced
Low speed control actuator - replaced
All coils have been checked and are firing
spark plugs have been replaced SEVERAL times - YES with BPZ8HS-10 and checked gap
plug wires have been checked
New battery
Throttle body is clean
Fan works and I use it

IT STARTING RUNNING RICH AT THE SAME TIME THE LOW SPEED CONTROL ACTUATOR STOPPED WORKING! - This has GOT to be some kind of clue or link. Does anyone know HOW the actuator works? It's just a reeve switch but where to the wires lead to? I can't find ANY wiring schematic that shows these wires.

I haven't taken the injectors out but if I can't find out what is making it run rich and load up then that's the only thing I can think of to do next but I won't do it until this fall. I can hold the throttle body open to get it to start now if it's flooded when I try to start it. 80% of the time it starts without me having to do that though. Plugs are black and wet.

Did I mention. . .IT STARTING RUNNING RICH AT THE SAME TIME THE LOW SPEED CONTROL ACTUATOR STOPPED WORKING! -

Please help.. .

 

[bhatch21]

Are you saying you replaced the Low Speed actuator switch and that function still doesn't work? To me, it seems like that switch tricks the TPS or ECU into increasing rpm. Have you tried running with it disconnected? Did the engine still seem rich? I don't really like the feature. If I wanted more RPM when the wheel is turned all the way, I would just move the throttle myself.

 

[SeptemberC]

Yes I replaced the low speed actuator switch and it still does not function.
I have not tried running it with the switch completely unplugged.

 

[bhatch21]

I would try running with the switch unplugged. See if it still loads up or is hard to restart. I haven't seen those switches on any Mercury wiring diagrams because I think Seadoo added them after the fact.

 

[SeptemberC]

Tried unplugging it and ran it today. [emoji26] no change.
I guess it could be a leaking injector but why would that keep the low speed actuator from working?
Sometime I wonder if it couldn't be a shorted wire somewhere. . .
I wish I knew someone that has worked on these before.

 

[bhatch21]

Bummer. Electrical problems are usually hard to find and easy to fix. You might pm Dr. Honda. He's an expert on the 240. If you can't get him, try your local Mercury Techs. Tell them it's just like the 2.5L EFI Mercury put in their outboards for years before switching to the Optimax. Good luck

 

[SeptemberC]

More info.... can anyone provide any help?

The low speed control actuator has continuity on both magnets. It also has continuity from the actuator to the engine. I'm attaching a pic of the plug at the engine where the yellow with black stripe that runs from the actuator ends. So I know it's working this far.... WHY would it not bump the rpm's?

I still have a running rich issue too. Sensors have been replaced along with the lift pump diaphragm. Computer scans show no errors or codes.
Come on guys.... I need some wild suggestions and/or out of the box ideas....

 

[bhatch21]

Try jumping the harness wires together where the low speed actuator plugs in. If you do this while the engine is running, according to guys on the other forum, the rpms should increase. If rpms don't increase, that would suggest the ECU is faulty for not responding to inputs. You might call these guys and ask about an ECU repair.
http://www.simonperformancetechnology.com/index.html

 

[Tim75]

It sounds like there should be a solenoid to pull or push the throttle slightly. I would think it would be mounted near the throttle arm linkage. Maybe it is disconnected or failed?

 

[SeptemberC]

Tim75 - it's EFI. no cords, cables... all electtonic from what I can tell.

 

[Tim75]

If no solenoid, what moves the throttle?

Does the ECU bump up timing? That would increase RPM.

Have you checked deep on the throttle linkages on the throttle body?

We may have entered the realm of pulling at straws.

 

[SeptemberC]

Yes I am assuming that the ECU bumps the throttle.
I would LOVE to find technical documents on it but have come up empty.
For what it's worth 2 Mercury shops have "examined" and hooked the diagnostic computer to it.
It was mentioned that Mercury may need to come in a do a reflash. Dealers can't do it but there's a Mercury guy that comes in every once in a while and he can do it.

I'm still looking for answers.