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Old 04-01-2008, 06:21 PM
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Default 525SC Carbs

I have a couple questions if anyone can help regarding Merc 1050 Dominator Carbs that were original equipment on the 525SCs:

1. What is stock merc jetting and PV on these carbs?

2. How is the boost referenced power valve achieved and how can I tell if some 1050 blue carbs are actually blower carbs?

BT

Last edited by blue thunder; 04-01-2008 at 07:23 PM.
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Old 04-01-2008, 09:25 PM
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Jets should be #98 all around. The carb is not boost refered, if I remember correctly PW is 6.5.

bl
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Old 04-02-2008, 01:38 AM
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Originally Posted by badluck
Jets should be #98 all around. The carb is not boost refered, if I remember correctly PW is 6.5.

bl

98's and 6.5's is correct. Stock jetting is rich. Not sure about the boost referencing. Mine did have a hose and pvc valve going to the carb base. My jetting was stock with 98's even with 7.5-8#'s of boost and it was fine. Went up about 4 sizes when added a roller cam.
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Old 04-02-2008, 04:05 PM
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Thanks for the replies. It sounds like merc jetted like there was no power valves thinking they will never open anyway.

BT
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Old 04-03-2008, 06:46 AM
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Blue Thunder- What jetting was in your carb? 98's? .... Does your carb have Power valves or not?


I have re-jetted many of these engines. I would run 93 jets square with a 6.5 power valve in the primary and 5.5 in the secondary. From stock jetting , on average the boat will pick up about 2 sometimes 3 MPH. Mercury likes to flood engines with fuel. I hope this helps.
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Old 04-03-2008, 11:09 AM
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Originally Posted by mrhorsepower1
Blue Thunder- What jetting was in your carb? 98's? .... Does your carb have Power valves or not?


I have re-jetted many of these engines. I would run 93 jets square with a 6.5 power valve in the primary and 5.5 in the secondary. From stock jetting , on average the boat will pick up about 2 sometimes 3 MPH. Mercury likes to flood engines with fuel. I hope this helps.

They have 98s square and 6.5 front and back. They were supposed to be stock and I just wanted to make sure. I was curious why merc would choose not to do the boost referencing? Do you boost reference MrHP when lowering the jets and PVs?
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Old 04-03-2008, 11:37 AM
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Originally Posted by blue thunder
They have 98s square and 6.5 front and back. They were supposed to be stock and I just wanted to make sure. I was curious why merc would choose not to do the boost referencing? Do you boost reference MrHP when lowering the jets and PVs?
I have boost referenced before, The carbs are under vacuum , running power valves is just fine. Run the jetting I stated above, if want want to start a bit richer install 94's. The engines will wake up! The other thing I want you to do is set the float levels with the bowl off. Invert the bowl (up side down) and with a pin gauge or clean drill bit, set the floats at 23/64 or .3594 measured in the center of the float/bowl. This will correctly set the floats so they are not too low or too high. The gauge should just slip under the top of the float.

Last edited by mrhorsepower1; 04-03-2008 at 04:41 PM.
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Old 04-03-2008, 12:00 PM
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Thanks much MrHP. I'll take that advise.

BT
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Old 06-27-2008, 06:20 PM
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Originally Posted by mrhorsepower1
Blue Thunder- What jetting was in your carb? 98's? .... Does your carb have Power valves or not?


I have re-jetted many of these engines. I would run 93 jets square with a 6.5 power valve in the primary and 5.5 in the secondary. From stock jetting , on average the boat will pick up about 2 sometimes 3 MPH. Mercury likes to flood engines with fuel. I hope this helps.
Would the same jetting apply to a 525sc that has an intercooler? I have one and right now it is jetted richer, plugs read rich=safe. I know there is room for improvement.
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Old 07-16-2008, 07:42 PM
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Anybody??
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