bob miller
Well-Known Member
- Joined
- Jun 28, 2007
- Messages
- 1,083
has anyone ever used a 7.5 k/b gold head , large crank , with a tuned pipe ???? what length did you set the pipe at ??? thanks.....bob
7.5 k/b outboard and tuned pipe
- Thread starter bob miller
- Start date
Help Support Intlwaters:
- Joined
- Apr 13, 2011
- Messages
- 6,347
Bob,
To get the "full effect" and highest RPM, you have to switch out the stock P/S for a pipe timing P/S. These were stock on the ducted fan motors but not the outboards. Set pipe length at 9.5", and fine tune from there. Good luck.
To get the "full effect" and highest RPM, you have to switch out the stock P/S for a pipe timing P/S. These were stock on the ducted fan motors but not the outboards. Set pipe length at 9.5", and fine tune from there. Good luck.
BradSpencer
Well-Known Member
- Joined
- May 7, 2009
- Messages
- 890
Hi Bob,
What pipe, hull and prop?
All the SS/air cooled gold head engines came with the liner which had the higher exhaust timing. 184 -186 deg from memory.
What pipe, hull and prop?
All the SS/air cooled gold head engines came with the liner which had the higher exhaust timing. 184 -186 deg from memory.
bob miller
Well-Known Member
- Joined
- Jun 28, 2007
- Messages
- 1,083
brad , the hull is hopper , 447 prop , bob kensill tuned pipe....what I,m most concerned about is over heating the motor ....thanks....bob
BradSpencer
Well-Known Member
- Joined
- May 7, 2009
- Messages
- 890
Nice hull/engine/pipe/prop combo.
Heat won't be a problem as long as you don't go excessively lean. If you have access to a BM 4 flow meter, 100 will be a good starting point, you will probably end up at around 110-115.
I can get you a measurement for the pipe length tonight. As these are custom hand made pipes, the ones I have vary slightly in volume/.
Heat won't be a problem as long as you don't go excessively lean. If you have access to a BM 4 flow meter, 100 will be a good starting point, you will probably end up at around 110-115.
I can get you a measurement for the pipe length tonight. As these are custom hand made pipes, the ones I have vary slightly in volume/.
bob miller
Well-Known Member
- Joined
- Jun 28, 2007
- Messages
- 1,083
brad , I don't have a flow meter
BradSpencer
Well-Known Member
- Joined
- May 7, 2009
- Messages
- 890
Are you using the standard K&B carb and K&B remote needle for that engine?
If so, set low speed mixture disk to full open/rich.
And begin with the needle at 3.5 turns out. Depending on variable with your specific setup you shouldn't need to go leaner than 3 turns out on the needle.
Below are a couple of pics as a guide for pupe length. Mine measures at 50mm from the header mount bolt to the first weld on the pipe. I am running a little more prop, and higher engine timing numbers, so this length should be a conservative starting point if your pipe is the same. Best to start a little longer and shorten the pipe as you go.
If so, set low speed mixture disk to full open/rich.
And begin with the needle at 3.5 turns out. Depending on variable with your specific setup you shouldn't need to go leaner than 3 turns out on the needle.
Below are a couple of pics as a guide for pupe length. Mine measures at 50mm from the header mount bolt to the first weld on the pipe. I am running a little more prop, and higher engine timing numbers, so this length should be a conservative starting point if your pipe is the same. Best to start a little longer and shorten the pipe as you go.
bob miller
Well-Known Member
- Joined
- Jun 28, 2007
- Messages
- 1,083
brad , I'm using the k/b carb and hs needle , thanks for the pictures....thanks....bob
