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1989 Evinrude Port Temperature Switch

L

loopie111

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1989 evinrude 140 tx. I suspected that my port temperature switch is bad because my idle timing is off by a lot. Reads 4 BTDC when it should read 8 ATDC. I have to back off the idle timing screw almost all the way and it starts to backfire when I get it to 8 ATDC. When I removed the sensor the aluminum housing was corroded and falling apart. Can I put the sensor back in without the housing? Can I test it in oil without the housing? These are 90+ each and I have 2 motors so I really dont want to replace them because the motors are giving me headaches. Does anyone have used working ones they would like to sell?
 
A cryptic post.
Temp switch has nothing to do with idle timing ignition, unless shortened and initiating SLOW.
May I suggest you get an OEM workshop manual to get your engine properly synched.
The important is to get pick-up timing correct, then idle timing will be whatever needed to get the engine to idle.
 
Sorry about not being clear. I'll start over. I have the omc manual and I have followed it to a T. Here is my problem. 1989 140 tx looper has a very rough idle until I get to about 1500 rpm's then it smoothes out and runs good all the way to WOT. I have rebuilt the carbs and inspected all of the ports and everything is clean. Replaced all of the fuel lines, Installed new fuel filter / water separator, checked primer, recirc system, compression, spark plug wires, stator, power pack, coils & thermostats. Everything has checked out within spec per the manual. When I tried to run throught the sync instructions (in the water under load) the idle timing was showing up as 4deg BTDC when it should have been around 8 deg ATDC. I had to back the idle timing screw almost all the way back to get it to be 8 deg ATDC and then it ran awful and wanted to stall. I was out of ideas and I thought that the port temp sensor could be bad causing the motor to stay in quick start mode until the RPM's went up. Per the manual it is a 10 deg advance which kinda makes sense.

The only thing that doesnt seem right is that I used a syringe to add fuel to each carb one at a time and they all bogged down except for CYL 1. I could add a lot of fuel and it wouldnt bog down at all. If I pulled the sparkplug wire it would barely run so I know the cyl was functioning.

Please let me know what I'm missing. I have twin motors and one is running fine so I have swapped all components to see if it fixes the problem with no luck.
 
To eliminate quick start from getting activated, remove the yellow/red from start solenoid to power pack and ground the white black from PP to temp switch. Then start engine.
I doubt you will ever get that engine running at idle and 8ATDC!
As you got two engines, just compare but remember they are 'individuals' and may not be totally identical in behavior or settings.
 
Do the carburetor throttle butterflies "all" start to open as they should when the scribe mark on the cam is dead center with the throttle cam roller?
 
Thanks for the response, I was testing the quick start last night and it appears that it is not engaging. I unplugged all of the temperature sensors and grounded the white/black from the powerpack. There was no change in engine operation with the wire grounded or not. I tested both engines with the same result. I did not unplug the red/yellow wire so I will try that tonight. What should I set the idle timing at? the omc manual calls for 8 deg ATDC. Can I set the idle timing using the cranking method with the spark plug wires hooked to a tester or is that for optical ignitions only? I will check the butterflies tonight.
 
What are the chances this fixed my problem? Tested all of the electrical components and found that the stator resistence is low 419 but the output is in the acceptable range of 150 v. Cleaned all of the coil grounds and check the spark 1,3 & 4 had a weak spark and 2 wouldnt spark at all. Decided to pull the flywheel and look at stator and timer base. Found the stator was rusty and paint was in the outer metal contacts. The timer base was also dirty. I cleaned and sanded all of the contacts and put eveything back together and tested the spark again. The spark was strong and "snaped" on all cylinders. Could dirty components cause this?
 
You did exactly what everyone seems to be afraid of "flywheel removal and inspection" You very well may have nailed it my friend. :)
 
problem was port temperature switch the quick start sensor was bad. Bypassed the swith and everything ran fine idles like a charm now. Thanks for the help.
 
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