Why wouldn't all the cylinders need the same air/fuel ratio?
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Triple carb motors with different jet sizing?
Why wouldn't all the cylinders need the same air/fuel ratio?
Fuel tends to "run down" into the lower cylinders.
On the earlier Merc triples (that fried their top pistons regularly) Merc used a .0785 jet in the top carb and a .072 in the bottom (it uses two carbs).
Jeff
"We live at the bottom of an ocean of air." - General Marvage Slatington
Each cylinder typically has a different temps and exhaust pulse as well, tune each cylinder on it's own based on piston wash and plug color
That is what I would expect! But perhaps there is a difference in design from one cylinder to the other that warrants such a change?......ex.( one of the crankcases powers a fuel pump or has an oil circulation set up or something, that lowers crank case compression, thus requiring a bigger jet for weaker intake)???Originally Posted by Tiller guy
I figured it was temp related, but so far all of the above sound like very good answers.
Tiller if you run that monster 25 past 6k keep the bottom hole one step rich.
Per this: http://www.groupk.com/tec-rearseize.htm
Good read and thanks for sharing.
Ah-hah! That answers a question that's been bugging me for years: One of Yamaha's triples has a different compression ratio on one of three cylinders. (It's in the sale literature.) Now I know why!
Jeff
"We live at the bottom of an ocean of air." - General Marvage Slatington
Well, after reading that one cylinder has lower compression by design and remembering this older reply here of mine, looks like I got the closest if not exact guess! But I figured it was something to this nature. Awsome!
One year of the OMC 56 had a cooling issue
the fix was a bigger jet in the middle cylinder
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