Mercruiser 5.0l TKS (2010 Bayliner 245)

[Nmforbes]

Hello all,
First post here in the forum.

I've got a question that hopefully some of you can help out with!
I've got a 2010 Bayliner 245. 5.0l Mercruiser TKS B3 leg.
When starting the boat (even if its only been sitting for 24 hours) it takes quite a while to get up to operating temp (170-180). During that time sitting in the slip I have to keep the choke in or else the engine will stall. It will usually take 20 mins + before I can actually put it in neutral and it will idle without dying.
Also during this time I get a very rich fuel/exhaust smell with some smoke. The smoke goes away once in neutral with no chokany advice would be appreciated and a picture of engine below for reference!
Thank you in advance!

 

[Nmforbes]

I should also mention the engine has 190 hours on it

 

[Bt Doctur]

you dont have a choke plate if its a TKS carb and you have no active control of the choke if you do have a choke plate
I have to keep the choke in or else the engine will stall.

 

[Nmforbes]

My mistake on that.
I push the button on the shifter to pop it into neutral so I can put rpm up with throttle.

 

[Nmforbes]

Or perhaps is it simple (standard carb idle screw) to increase the idle?

 

[badrano]

If your engine is taking a long time to warm up, have you checked to make sure the thermostat isn't stuck open?
I'm kind of thinking the diode in the TKS circuit is blown open. If it is, the TKS module is not being energized while the engine is warming up there by keeping a rich mixture going longer than it should. Once the engine reaches temp, the TKS temp switch will close which will then energize the TKS module which will eventually close up the rich mixture port and that's probably when you're able to go back to idle without it stalling.

When the engine is warming up, do you hear a hissing sound?

When the engine reaches temperature, does the hissing sound continue or does it eventually stop after a bit? Or does the hissing sound stop before the engine reaches temperature?

My last boat had a 5.0 TKS and the hissing would stop somewhere in between a cold engine and the engine reaching temperature.

Look at the harness between the carb and shift linkage. You'll see what looks like a connector with a reddish cover zip tied to the harness. That's the diode. If you know how to test a diode with an ohm meter, check to see if it's open.

 

[Nmforbes]

Everything in your post makes absolute sense.
I'm heading out to check on the boat this weekend, ill check on that and report back.
I assume the hissing sound is the TKS? I haven't paid close attention to that but I will now.

If for instance the diode is bad, simple as replacing it?

Odd because the boat literally just came out of the shop for a tune up and this is how its been acting.
Its being kept in a boat house so I'm really trying to rectify this issue as it absolutely chokes anyone who is in the boat house while its warming up with a very rich fuel smell.

Thank you for your response and will report back asap

 

[badrano]

The TKS carbs have that distinct hissing sound. I never really heard it on my last boat unless the engine cover was open.
Replacing the diode is as simple as fuse.
Hopefully it is just that.

 

[Scott06]

20 minutes to get warm is a long time check the thermostat frirst. Yiu may need a carb cleaning and rebuild as well but take take of first things first