Hi Scott your the engine man i do believe and am considering a carb change.You have seen my boat go so was wondering if i change the carb from a 167 to a 813 fitted with the accelerator pump would i notice the difference & would there be any gains to be had? Cheers Darren

Listening to engine run it does not sound as if it is really spinning very high rpm.
So best guess would be the CFM capacity of the 167 carb is still not really being met. Going to a larger carb really is not going to do anything for power IMO.

Until engine/prop/pipe combo really starts to sing and carb becomes the restrictive part of producing more power at high rpm your better off fiddling around with other parts of your set up.

Thanks Scott,think it was yourself that mentioned about my pipe RTC saying they were a little long so do you think pipe type length needs addressing to get the RPM up?if so this will be the way i will go next.Cheers Darren

dazzido wrote:
If indeed you are using a Wrap To Center header, systems tuned OAL is too much.
Your pipe likely fine, just need to go 100/105* on header type and establish correct length for engines tune and load.

Give that a go in next few weeks Scott,thanks for the knowledgable advise cheers.Darren