mac .67 + ab67 burning lot of plug

[dozz]

Hi i have a hard time with my boat this summer , i have hydroplane 48x24 with a mac .67 and ab67 tune pipe set at 10.5 and i burn a plug each time i go in the water

when i'm too rich the boat dont go well and i lean my engin and when he go very well each time i burn my plug

i don't find the right setup of the engin

i have another boat with a k.45 and i have no problem with it

i have check every thing change my gaz line change my tank and check all presure hose and always the same problem

my boat run well 1-2 turn after he stop for nothing or i burn another plug again :angry: :angry: :angry:

or my engin go fast and sudenly go slow go fast and go slow i have weird problem with this boat

i run red max 50% fuel and my plug is mccoy9 and my head is shim at .0012

i try everyting this summer and dont found the fiability of this boat

any one have hard time like me in the past with a similar set up

thank

Pat

 

[namba276]

Try more head clearance.

Bob

 

[piper_chuck]

Hi i have a hard time with my boat this summer , i have hydroplane 48x24 with a mac .67 and ab67 tune pipe set at 10.5 and i burn a plug each time i go in the water when i'm too rich the boat dont go well and i lean my engin and when he go very well each time i burn my plug

i don't find the right setup of the engin

i have another boat with a k.45 and i have no problem with it

i have check every thing change my gaz line change my tank and check all presure hose and always the same problem

my boat run well 1-2 turn after he stop for nothing or i burn another plug again :angry: :angry: :angry:

or my engin go fast and sudenly go slow go fast and go slow i have weird problem with this boat

i run red max 50% fuel and my plug is mccoy9 and my head is shim at .0012

i try everyting this summer and dont found the fiability of this boat

any one have hard time like me in the past with a similar set up

thank

Pat

Every time I've had the problem marked in bold it's been because the pipe slipped a bit shorter. A short pipe is also bad on plugs. On the CMD tuned pipes page, Andy recommends 11" for the .67 parabolic pipe and 10.8" for the AB67 pipe. Lengthen the pipe and try again.

 

[Ray Sametz]

What prop you running?????? B) B)

 

[dozz]

i have x457 for props

 

[Rokieboater]

The right prop will make alot of difference.

 

[ALLAN YUEN]

which one blue or silver headed for MAC67?

which one black or silver with welded pressure fitter for AB 67 pipe? or CNC bullet AB67? Set up 11.25"

put more shim head clearance .014

maybe check your remote value sometime bad leak o ring? and fuel filter clog( inside dirt)?

Hope help to work

 

[dozz]

thanks guys

i have blue head mac67

silver ab67 with bullet small one

i think i have bad leak someware because i have 2 mac67 and i try both with same issue..... burn plug

oh well....maybe one day i found the trouble