Out of options please help

[Fordracing17]

1994 mercury xri 200. This thing is a nightmare the problem is bogging out of hole. I step on hotfoot and rpms rise to about 3000 and cut out then won't run but 2000 rpm. Then the next day runs like a scalded ape. It is intermittly but as time goes on it is getting more frequent. The following is a list of parts and some things I have done.

Low pressure fuel pump
High pressure pump
6 plugs
6 wires
6 coils
2 switch boxes
Trigger
Stator
All fuel line boat and motor
Replaced all filters
Cleaned vst
Made resistor circuit bypassing various sensors to rule out sensor problem
Checked tps in spec
Has 40 psi of fuel pressure

Thanks

 

[Flashoney]

I checked tps operation and found a dead spot in it hooking a volt ohm meter between two wires not the Orange wire with key on Engine off and both brown with White striped disconnected on head unhook hotfoot at Engine and move throttle observing reading voltage increases Smoothly up to 7.46 I'm having close to the same problem with my 1999 200 mercury efi may be different on your motor you can find the manual on line for particular on your motor good luck taken mine Monday for link and synk timing check and tps set and checked I will update you what they find

 

[Fordracing17]

Anybody??

 

[Dukedog]

tha little coned shaped filter in tha U shaped hose?
you need ta get hold another ecu that is a known good one... any will do... 150, 175, or 200... analog or digital..a1 ta a30 don't mater.. also all aspects of tha efi harness needs ta be checked... it can be a nightmare.

 

[Fordracing17]

Thanks for you help

 

[CharlieB]

Hotfoot? I imagine this is NOT just a fishing motor and you are maybe racing?

How much idle time is it running before you hit it? What spark plugs are you running?

When it bogs and won't run up have you ever immediately shut it down and pulled the plugs to see what they look like?

I suspect you will find they are very wet, near fuel fouling.

I also imagine you are running the spec'd surface gap plugs. These plugs are fine for high speeds but do not like a lot of idling time, they tend to oil up, carbon builds and can foul on the hit. You can either try a standard electrode plug like the NGK B8HS or if there is piston clearance the extended tip BP8HS. Or just prior to the hit bring up the RPM in Neutral to clean out the cylinders a bit, fast idle about 3K for 3 - 5 seconds before dropping into gear and making your holeshot.

Double check the TPS idle setting, if voltage is not spot on it may be idling a hair rich, contributing to loading the plugs.

 

[Fordracing17]

Charlie thanks for input I am running NGK bu8h this is the second set. I use to put in neutral Rev alittle then throw in drive and go. The plugs are wet when I put in neutral and Rev it smokes like a sob. I figure it is running rich. I bogged about 2000 rpm the other day for 40 min then let out and got back in it and boom took off. Should I switch plugs to something other than what I'm running is the tps the only thing that would cause it to run rich what are chances that detonation module is messing up thanks for help

 

[CharlieB]

I'd have to look to see if that unit has the dreaded idle stabilizer module. If so, 86 it and reset WOT Timing.

TPS, temp sensor reading out of range. The factory service manual has the best troubleshooting guide for EFI's

NO return on electrical parts so you MUST test carefully according to the service manual before condemning any electrical part.