Mercarb 2 barrel TKS jet sizes?

[WrenchNhammer]

I didn’t realize there were different size jets when I broke my carb down for rebuild. The 2 barrel mercarb TKS goes on a 5.0 Mercruiser. Does anyone know which ones goes where?

 

[Rick Stephens]

What's the serial number on the motor? I couldn't find a TKS for the 5.0L.

 

[WrenchNhammer]

0w372603

 

[Rick Stephens]

There's three part numbers. Stock is #3302-9058. These are marked 1.65. Always run two identical jets in the 2 barrel Mercarb.

There is also a larger jet available to run richer - #3310-866283

There are only 2 jets installed, so probably one or the other. From what I can see the second number may be for the 5.7L motor.

 

[Scott06]

I didn’t realize there were different size jets when I broke my carb down for rebuild. The 2 barrel mercarb TKS goes on a 5.0 Mercruiser. Does anyone know which ones goes where?

The two jets should be the same size left or right barrel doesn’t matter

 

[WrenchNhammer]

There are 3, one is off to itself

 

[Scott06]

There are 3, one is off to itself

the one off by itself is the power valve and has a different shape to it. The main jets are just an orifice where the power valve has a spring loaded plunger on it.

 

[WrenchNhammer]

Different shape?

 

[WrenchNhammer]

Not the one in the bottom of the bowl. I’m guessing the two larger ones go to the 2 barrels and the smaller one off to the side

 

[achris]

Which manual are you using?

 

[achris]

 

[Scott06]

Not the one in the bottom of the bowl. I’m guessing the two larger ones go to the 2 barrels and the smaller one off to the side

Yes this is outlined in chris chart. The smaller one is the enrichment jet for cold starting

 

[WrenchNhammer]

I think I got it straightened out thanks. So just so I understand, the enrichment is only used during cold start and the 2 main jets supply fuel on the regular?

 

[Bt Doctur]

would have been bettor off with a standard 2 barrel

 

[WrenchNhammer]

That’s what I’ve gathered. First boat I’ve had with a carb and I don’t care much for it. First I didn’t realize they were different sizes and put the enrichment jet in the other and it had me stumped lol

 

[Scott06]

I think I got it straightened out thanks. So just so I understand, the enrichment is only used during cold start and the 2 main jets supply fuel on the regular?

Yes the enrichment valve basically replaces a choke system, to provide for richer fuel mixture when starting. Idea was since no one drives a carbed vehicle anymore and knows how to set the choke beore starting ... that you can just walk up trun the key and starting like injected engine...

Yes the main jets supply fuel during normal operation, the carb will run off the idle (mixture screw at carb base) and then transition circuts until there is enough airflow through the venturi to start siphoning gass out of the mains. I think this is normally about 1500-2000 rpm before the mains start dribbling fuel. Look down the bores while you advance the throttle you can see this happening.

 

[WrenchNhammer]

Good to know thanks bud

 

[nola mike]

Yes the enrichment valve basically replaces a choke system, to provide for richer fuel mixture when starting. Idea was since no one drives a carbed vehicle anymore and knows how to set the choke beore starting ... that you can just walk up trun the key and starting like injected engine...

It's not like a secret handshake that nobody tells you about. If pumping the throttle twice is the hardest part of my day, that's a pretty good day.

 

[Scott06]

It's not like a secret handshake that nobody tells you about. If pumping the throttle twice is the hardest part of my day, that's a pretty good day.

only if you have a beer in the other hand.... agreed its not that hard to figure out....

 

[WrenchNhammer]

And you still have to pump it twice. What a joke