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Originally Posted by larose481
(Post 4683749)
What part number is the intake? If it's a square bore intake there may not be enough flange to seal the carb on a spread bore carb. Edelbrock makes an adapter plate that's only an 1/8' thick for just this. Might be sucking air around carb base.
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Originally Posted by SB
(Post 4683750)
This one ?
https://www.summitracing.com/parts/c...44-4/overview/ Brand:COMP Cams Manufacturer's Part Number:12-244-4 Product Line:COMP Cams Xtreme Marine Camshafts Summit Racing Part Number:CCA-12-244-4 Cam Style:Hydraulic flat tappet Basic Operating RPM Range:2,000-6,200 Duration at 050 inch Lift:234 int./244 exh. Advertised Duration:278 int./292 exh. Valve Lift with Factory Rocker Arm Ratio: 0.498 int./0.500 exh. Lobe Separation (degrees):112 If so, yeh,exhaust sucking water back is a huge possibility #2, engine will probably ant initial timing somewhere between 16-20* BTDC #3 the stock carb metering will be out too lunch. don't know what to suggest with your cam/comp....can't help you there as cams that large I have a Holley Carb on it. |
Same cam, same cam part # . CCA-CL12-244-4
You just linked the cam + lifter kit. # CL12-244-4 |
Originally Posted by SB
(Post 4683753)
Same cam, same cam part # . CCA-CL12-244-4
You just linked the cam + lifter kit. # CL12-244-4 |
Some good Qjet idle/low speed tuning info linked below.
Drilling Qjet Idle Tubes- Fact, or just BS ?? - Performance Years Online Forums |
Those cams are going to want a lot more ignition advance at idle too.
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Originally Posted by SS496
(Post 4683811)
Those cams are going to want a lot more ignition advance at idle too.
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Bump it to 20* initial (idle) ......but DO NOT drive the boat like that since that will likely be overtimed once the centrifugal advance kicks in....this is simply seeing what it wants for idle timing.
You will likely need to reduce the amount of centrifugal advance so you can run more initial and not overtime the engine while running at higher RPM under load. What is your total timing now? |
Originally Posted by SS496
(Post 4683815)
Bump it to 20* initial (idle) ......but DO NOT drive the boat like that since that will likely be overtimed once the centrifugal advance kicks in....this is simply seeing what it wants for idle timing.
You will likely need to reduce the amount of centrifugal advance so you can run more initial and not overtime the engine while running at higher RPM under load. What is your total timing now? |
Originally Posted by SS496
(Post 4683815)
Bump it to 20* initial (idle) ......but DO NOT drive the boat like that since that will likely be overtimed once the centrifugal advance kicks in....this is simply seeing what it wants for idle timing.
You will likely need to reduce the amount of centrifugal advance so you can run more initial and not overtime the engine while running at higher RPM under load. What is your total timing now? |
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