TKS issues with 3.0 Where does the power supply link?

[perna00]

I've got a 2007 135hp 3.0 mercruiser alpha 1 with the tks carb (bayliner discovery 195). The choke (tks) solenoid stopped working. As a temporary fix I adjusted the idle up slightly and pump the throttle about 8 times before starting. Rough start but is perfect after it warms up. I went to trouble shoot it and there is no power going to the TKS solenoid. It says it gets power from the oil pressure but I don't know where to chase the wiring unless I remove all the harnesses and ties. Anyone have to trouble shoot the solenoid that could lend me some advice...?

 

[poconojoe]

Go on the bayliner site. They have manual supliments to download. Mine (185br) had the wiring diagram.

 

[alldodge]

I've got a 2007 135hp 3.0 mercruiser alpha 1 with the tks carb (bayliner discovery 195). The choke (tks) solenoid stopped working. As a temporary fix I adjusted the idle up slightly and pump the throttle about 8 times before starting. Rough start but is perfect after it warms up. I went to trouble shoot it and there is no power going to the TKS solenoid. It says it gets power from the oil pressure but I don't know where to chase the wiring unless I remove all the harnesses and ties. Anyone have to trouble shoot the solenoid that could lend me some advice...?

The oil pressure switch provides a ground to the YKS module. 12V is applied via 1 20amp fuse via the engine circuit breaker.

 

[perna00]

Thank you Alldodge! Bayliners website does not list info on a 195 discovery.

 

[perna00]

So researching a little more I found that a common problem to the TKS system is that the Diode assembly that gives the fuel enrichment module power will short and fail. This would be why it ran rough/smooth for so long and finally gave out. It seems that the Diode will fry and even back-feed power to the fuel pump...which would be why the engine would take 30 seconds to shut off after the key was turned off when it was running bad. Hopefully this will save a few people from spending $200+ on the solenoid vs a $20 diode assembly. Part# if interested is: 83-865913A01

 

[flyman219]

" This would be why it ran rough/smooth for so long and finally gave out. It seems that the Diode will fry and even back-feed power to the fuel pump... "

I'm pretty sure you have a mechanical fuel pump on your motor. Another "switch" that can affect your TKS solenoid is the temperature sensor. This sensor prevents the solenoid from activating (opening up the enrichment passage) while the motor is at running temperature preventing flooding at start ups. If this has failed you may be getting a false running temperature condition preventing the solenoid from activating.

But now I see you are having a no power issue at the solenoid so this may be a moot point.

Mike

 

[perna00]

Well, I just found out there was a fuse blown on the circuit. It was hidden behind the wiring harness against the engine. I now have power going to the solenoid and it extends/contracts with voltage so it appears to be working fine. Only downside is that it still doesn't idle up on a cold start. I even moved the seal in the passage and it appears I am not getting any fuel to be pulled though the passage. I took a small gauge wire and cleaned the passage between the throttle body opening and the port at the solenoid. Afterwards I sprayed carb cleaning through it and it idled up like it should. It seems it isn't getting any feed from below. How is the carb setup? It is supposed to be a passage or tube going into the main bowl of the carb or is it a different setup? I can't see inside the area without removing the entire carb from the engine. Is there a passage I can clean...If so, is it located in the back or bottom of the port? Thanks for any advice.

 

[flyman219]

Here is a link that might help you for the TKS Carbs.

http://boatinfo.no/lib/mercruiser/manuals/mercruiser41.html#/36

Mike

 

[perna00]

Thanks for the link Mike; very helpful. I went ahead and measured the Solonoid and circuits and all is working like it should. The only thing left was the ports so I removed the top of the carb. I'm thinking the gasket was ripped because the bottom port below the throttle plate was open and I never even heard hissing when the solenoid was removed.

 

[perna00]

One last questions...could it be anything other than the gasket? It seems to be a simple siphon system so I'm not sure what else it could be?

 

[flyman219]

So what you should hear when you have a cold start (choke needed) is a hissing noise, similar to a pretty good vacuum leak. After about 8 minutes the motor will reach temps and the solenoid will begin to close the enrichment circuit. You will hear the hiss begin to get reduced to nothing, then the motors RPM's will drop because the mixture is leaned out to the idle adjustment mix. At that point the solenoid should not allow enrichment until the motor drops to a cold start temperature.

Mike

 

[perna00]

So I figured it out. Thanks for all the help guys. What happened was carb gasket got damaged and caused a small air leak. Usually not a big problem except that the gasket is what seals the air port that pulls the air/fuel mix from the TKS solenoid. As soon as I replaced it, the suction is back, hissing during warm-up resumed, and the boat started within 2 seconds without priming or stutter! Blown fuse must have just been coincidence.

 

[Fun Times]

carb gasket got damaged and caused a small air leak.

Just for better clarification purposes, What gasket did you need to replace? The base gasket, http://www.mercruiserparts.com/Show...g&inbr=12824&bnbr=60&bdesc=Fuel+Supply+System

Or the intermediate gasket, http://www.mercruiserparts.com/Show...37190.png&inbr=12824&bnbr=70&bdesc=Carburetor

 

[perna00]

The intermediate gasket (#35 in the second pic). There is a air passage about 2" long channeled out of the mating surface of the carb. The only thing that seals the log run is that gasket.