Rebuilt my mercarb, now runs awfully

[Zacattack]

Good evening,

I recently rebuilt my 2005 3.0 TKS carb and now it runs awfully. Seems lean (small white smoke) when I first start it. Then seems rich (black smoke) after it warms up and the TKS finishes. Prior to the rebuild it ran great, just didn’t idle. Any idea what it could have been that I did wrong? I’ve have the carb off 3 times now fiddling and adjusting but nothing changes. I’ve also spent hours with the idle mixture screw but to no avail. It idles at around 800 and when I give it some throttle it spews out black smoke and unburnt fuel. Thank you

 

[alldodge]

The carb is flooding
The bit of white smoke on start up is unburnt gas

The most likely issue is the float level and could be the float weight

 

[Pmt133]

Just out of curiosity, which mounting gasket did you use? I ask because a lot of the kits come with a thin gasket which I had issues with for a while chasing weird idle and bogs and just poor driving habits. There is a thicker, 3/16 or so mounting gasket that corrected all of that.

I don't think it is your issue, and agree it may be adjustment related on the float as with mine you could drive around that problem. But still something else to check.

 

[cyclops222]

Agree with a float being not adjusted correctly. Did you change any little Float parts ?
Some carburetor kits have rubber tipped float pins. Original tip can be all Brass. And some carbs are very touchy to rebuild correctly.
I assembled ta carb 2 times. Then I found a new MISSING part . Laying on the floor.
After that error. I cleaned the workbench completely. Then laid down a CLEAN LARGE white only, Beach Towel to do any rebuilds. Works much better now.

 

[Bt Doctur]

could by a standard 2bbl on ebay thats not painted inside for around $90

 

[Lou C]

either the float is too high, sticking, or the needle valve isn't holding (sealing off fuel flow).

 

[Zacattack]

The carb is flooding
The bit of white smoke on start up is unburnt gas

The most likely issue is the float level and could be the float weight

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Thank you for all that info specific to my carb. It ran a little better with those adjustments. But still awful. I even tried an Amazon carb. And it ran perfect for about 20 seconds. Then back to running poorly again (black smoke). Have a mechanic coming around in a week. Really hoping it isn’t anything major. Just confused as it ran absolutely perfect the day before I rebuilt the carb.

 

[Grub54891]

Have you ever rebuilt any carbs in the past? The reason I ask is: It’s always awkward the first time“ as with many things in life…..

 

[Scott06]

Thank you for all that info specific to my carb. It ran a little better with those adjustments. But still awful. I even tried an Amazon carb. And it ran perfect for about 20 seconds. Then back to running poorly again (black smoke). Have a mechanic coming around in a week. Really hoping it isn’t anything major. Just confused as it ran absolutely perfect the day before I rebuilt the carb.

Have you checked the fuel pressure? is the bowl over flowing , fuel dripping from boosters?

Using the correct base gasket so there are no vacuum leaks

 

[airshot]

Did you follow all the setup and measurements in the rebuild kit ? They need to be followed to the T....

 

[jimmbo]

The TKS does something to Enrich the Mixture, to speed up a Cold Start. Did that get messed up?

How does TKS work (technically)?

Curious about the mechanics of the TKS system. There is no choke so how does that work? What causes the hissing sound it makes until things warm up? What are the mechanics of it all? Nothing is broken, just curious how it works from a technical perspective compared to a traditional carb.

forums.iboats.com

 

[Lou C]

Hmm could it be on when it's not supposed to be ON?