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riverrat00
MMT Pro Member
Joined: Sat Jun 11, 2016 2:29 am
Posts: 92
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 Twin Carb Jetting/Tuning Anyone know what a good place to start on main and pilot jet sizes would be. I have a 180 main and 0.30 pilot now. It is running way too rich at idle and can't tell whats happening after due to the plugs being fouled. Engine has ported head, rods, pistons, exhaust, and cam.
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| Tue Sep 27, 2016 1:46 pm |
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brycecheramie
MMT 1000 Club
Joined: Thu Nov 04, 2010 7:38 am
Posts: 4323
Location: Cut Off, La.
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Re: Twin Carb Jetting/Tuning Hell, I don't even think people are running that big of a main jet in the single carb motors, much less 2 carbs.
Hopefully someone can help you! I never messed with dual carbs
_________________
Refurbishing a Prodrive
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| Tue Sep 27, 2016 7:07 pm |
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scarygary
MMT Pro Member
Joined: Fri Aug 29, 2014 2:36 pm
Posts: 442
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Twin Carb Jetting/Tuning 165main 25 pilot
If you have a stage 3 all bells whistles what you have will work in 50degree air and 103 octane. I have to rejet for winter and summer
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| Wed Sep 28, 2016 6:34 am |
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riverrat00
MMT Pro Member
Joined: Sat Jun 11, 2016 2:29 am
Posts: 92
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Re: Twin Carb Jetting/Tuning Sounded like a lot of fuel to me too. Thanks for that Gary I'll start there. Is there anything else you have found adjusting that would improve overall performance?
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| Wed Sep 28, 2016 7:42 am |
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Got Dux
MMT Pro Member
Joined: Mon Feb 14, 2011 11:12 pm
Posts: 103
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Re: Twin Carb Jetting/Tuning What altitude are you guys jetting at? We are 120' to 440' where I boat. Noticed huge performance improvements under 30* F.
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| Wed Sep 28, 2016 7:50 am |
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cb5331
MMT Super Elite Member
Joined: Fri Dec 18, 2009 8:10 pm
Posts: 16915
Location: Rowlett, TX
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Re: Twin Carb Jetting/Tuning
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| Wed Sep 28, 2016 8:22 am |
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scarygary
MMT Pro Member
Joined: Fri Aug 29, 2014 2:36 pm
Posts: 442
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Re: Twin Carb Jetting/Tuning I been running duels for the last 3 years. They have done great for me. I found that once you know what jet size you motor likes it's really easy to maintain. As far as adjusting carbs. Nothing to it and once I set carbs up for winter I don't touch them till I either rejet. If you put a jet in that gives you the best of both worlds then you may only adjust mixture screw 1 time a year.
I guess some guys can't figure out how simple it is or they listen to everyone else that don't really know how to adjust even if they never had twins.
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| Wed Sep 28, 2016 9:11 am |
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riverrat00
MMT Pro Member
Joined: Sat Jun 11, 2016 2:29 am
Posts: 92
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Re: Twin Carb Jetting/Tuning I'm somewhere around the same elevation. The stock jetting very well could be for the elevation and normal temps in Utah. No problems here either Gary, just needed a starting point to not avoid purchasing all those jets and smoking a case of plugs. Thanks for the help guys.
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| Wed Sep 28, 2016 10:14 am |
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scarygary
MMT Pro Member
Joined: Fri Aug 29, 2014 2:36 pm
Posts: 442
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Re: Twin Carb Jetting/Tuning RR I found the 25 pilot and 170 main are good here in Louisiana. Now if you idle a lot even the 170 will be a little rich. But when you wide open your plugs will look light brown. I'm running a good bit of compression so pump gas is not my motors friend unless I mix 104 octane in the gas. It will run on pump gas but it don't like it.
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| Wed Sep 28, 2016 11:24 am |
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cb5331
MMT Super Elite Member
Joined: Fri Dec 18, 2009 8:10 pm
Posts: 16915
Location: Rowlett, TX
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Re: Twin Carb Jetting/Tuning Why would the main affect the idle?
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| Wed Sep 28, 2016 11:32 am |
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scarygary
MMT Pro Member
Joined: Fri Aug 29, 2014 2:36 pm
Posts: 442
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Re: Twin Carb Jetting/Tuning
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| Wed Sep 28, 2016 6:37 pm |
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