Tractorsaw1
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So is this in waiting for carb?
Stroking a Dolmar 7900
- Thread starter Fruecrue
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Tractorsaw1
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I went with the tillotson 296 - only issue I have is at times the throttle hangs up at fast idle
Roost426
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So what are the benefit's of the twin jet? Just the fact it is able to be modded? They will both run the same on a stock saw? My smurf has the twin jet since it has been previously modded by someone and I rebuilt the carb on my stock 7900 but can't remember what it looked like inside might have to check again.
mettee
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I think its that they take the carb mods better. They meter correctly and such. @Terry Syd or @Poleman will have to explain that better
Terry Syd
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The twin jets are easy to mod for lots of different size engines. They are also designed similar to the Mikuni diaphragm carb.
The flow in the idle/transition circuit is controlled by a jet, not the 'low speed' needle. The 'low speed' needle is actually ONLY a mixture control for the idle. The idle circuit also has a long thin channel to set up a 'freight train' of bubbles and fuel to the idle port so that the idle mixture is more uniform. It is just a well designed carb.
There are different functions of a carb. Idle mixture, transition, total low speed circuit flow and high speed circuit flow.
Whereas if you are working with a Walbro HD, if you tweak the low speed needle you change the idle mixture, transition and also the total flow in the low speed circuit.
In the Zama you can tweak each function separately, that makes it a much easier carb to dial in.
The flow in the idle/transition circuit is controlled by a jet, not the 'low speed' needle. The 'low speed' needle is actually ONLY a mixture control for the idle. The idle circuit also has a long thin channel to set up a 'freight train' of bubbles and fuel to the idle port so that the idle mixture is more uniform. It is just a well designed carb.
There are different functions of a carb. Idle mixture, transition, total low speed circuit flow and high speed circuit flow.
Whereas if you are working with a Walbro HD, if you tweak the low speed needle you change the idle mixture, transition and also the total flow in the low speed circuit.
In the Zama you can tweak each function separately, that makes it a much easier carb to dial in.
Last edited:
redline4
I'm huge in Japan
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Looks and sounds real good!
