1995 150hp mercury efi too rich

[kakise36]

The motor keeps running rich on fuel and will shut off after running for extended period of time. The spark plugs are always wet with fuel and it smokes excessively. When running on the river the motor will begin to die down and pick back up and if you put it in neutral, it will shut off. I have replaced all of the fuel and put in new gas that is mixed at 50:1. I have checked the head temperature sensor and the intake temperature sensor. The throttle position sensor checks out fine on the ohm test but reads 7.5v when trying to adjust it no matter how far you turn it. I have tried 2 different tps sensors and both have the same outcome. I have been trying to adjust it with the head temperature sensor disconnected and the throttle shut.

 

[Dukedog]

do you have an oem manual?... if not pm an email address and i'll send ya a couple pdf's.......... would save lottsa typin' on guess's with what may or may not be goin' on with it...
most all smoke a lot more when oilier removed and pre-mixed.. especially at idle and slow rpm... should not effect tha way it runs.. a syn. blend and/or full syn. oil helps with excessive smoke some.

 

[kakise36]

I am running pennzoil marine oil and i have the oem boat manual.

 

[Dukedog]

is this what it shows for tpi stuff...

TPI voltage reading shown below. .135 ? .010 Models with ECM P/N 14632A13 and below. .250 ? .010 Models with ECM P/N 14632A15 and up and 824003-1 and up. .250 ? .050 Models with ECM P/N 14632A16 and up. IMPORTANT: If engine appears to run too rich or too lean, TPI can be readjusted. Decreasing voltage yields leaner mixture. Increasing voltage yields richer mixture. Allowable TPS range: .200 - .300 volts. 7) Tighten TPI screws to 20 lb. in. (2.0 N? m) holding correct tolerance. 8) Disconnect remote control cable from throttle lever. 9) Slowly move throttle lever to full open position while monitoring voltage reading. Voltage reading should increase and decrease smoothly. 10) Set volt meter to 20 DC volts. Maximum voltage reading at full throttle is approximately 7.46 volts. 11) Remove test lead and reconnect TPI harness to EFI harness. 12) Reconnect TAN/BLACK engine head temperature sensor leads located on port cylinder head.

 

[kakise36]

Yes it is the same except mine didn't have the tpi voltages for the different ecms, it just said it needs to be between .2 and .3v. The voltmeter keeps showing that i am getting 7.5v even with the throttle shut and no matter how you rotate the sensor it keeps displaying 7.5v.

 

[Dukedog]

yours should be tha 824003 so tha .25 +/- .10 applies.. if your not gettin' any change then something is outta whack.. usin' merc test harness?.. can dig a little for tha ohms testing values but not many use it.. its used mostly when there is no 12v power to tha power head.. kinda "ole school"..........

 

[kakise36]

I don't have the mercury test harness. I've just been piercing the insulation on the sensor wires.

 

[Dukedog]

blue and tan/beige/brown (sometimes its kinda in between tha color) as long as its not orange!

 

[kakise36]

i'm supposed to test the blue and the tan? I've been doing the orange and tan.

 

[Dukedog]

not orange..... blue/tan

 

[kakise36]

I got the sensor set now, but it is still smoking and there is fuel or oil coming out in the exhaust inside the prop.

 

[Dukedog]

thats tellin' ya its way fat with unburnt fuel/oil mix.. could be several things from ecu ta plugs with all things in between.... ya might need a dva to check some of tha stuff.....

 

[kakise36]

I ran a vapor separator test and it had fuel coming out of the hose. I took it apart and couldn't find any dirt on the needle valve, so i put it back together and it still has fuel coming from the hose.

 

[flyingscott]

What is your fuel pressure at?

 

[kakise36]

between 32 and 38 psi with only ignition switch on. i unhooked the intake air temp sensor and put the wires together and engine noise and smoke didn't change. According to the book that should cut the fuel back by 10%. I unhooked a vacuum line on the starboard side of the motor that enters the back of the ecu (guessing it is the map sensor) and sucked on the line with my mouth and it didn't change the smoke or engine noise. I tested the spark at 7/16" and it was blue on all plugs.

 

[kakise36]

No Title

 

[Dukedog]

check tha ecu plug.. its not tight.. look at pins for any lose and/or bent.. that hose is supply from mech. pump.. should pump fuel anytime motor is turned over.. vst float, needle and seat controls fuel level in vst.. still several things that could be tha culprit.. would help if you had acess to a known "good" ecu to swap for testin'.. thats something that needs to be eliminated or found ta be bad!............ any horsepower (150/175/200) ecu will work for testin...

 

[kakise36]

I have checked the plug and it is fine, I ordered an ecu and it will be in after 2 weeks.

 

[Dukedog]

collar needs ta be screwed up tight!.. doesn't look like it?... used or new ecu?.. new should be nla?.. used is crap shoot no mater what tha seller says...

 

[kakise36]

The wiring harness is as tight as it will go. It is used, but is returnable.