Re-Jetting for Economy

[linckeil]

I'm currently rebuilding the WMK-9 carbs on my 1972 1400 inline 6. All 3 carbs have a .080 jet in them.
Should I consider a smaller jet, or will that just mess things up?
A small sacrifice in performance would be made if a noticable increase to fuel ecomony is realized.
Any suggestions? Or should I leave it as it is?
Thanks.

 

[Laddies]

Re: Re-Jetting for Economy

You might save a tiny amount of fuel but might burn a large hole in a piston

 

[hkeiner]

Re: Re-Jetting for Economy

I believe you are thinking of running your motor at WOT with a more lean calibrated high speed fixed jet. Don't do that. I understand that the fixed high speed fuel jets are changed from normal spec ONLY when running the motor at a higher altitude. One would not change them to save fuel. Running a motor leaner than specified for the altitude it is run at is VERY BAD for the motor. Piston meltdown and other overheat related damage.

 

[steelespike]

Re: Re-Jetting for Economy

Running with smaller jets than recomended will cook your motor.
Only solution for efficiency is to optimize setup,prop, weight removal/distribution.
maybe something like smart tabs so you can stay on plane at a lower rpm.
your 1400 will use about 14 gph(gallons per hour)at wot (wide open throttle).
Be sure it is in fine tune and your setup is on the edge and you will get your best mileage.

 

[WillyBWright]

Re: Re-Jetting for Economy

If you do go smaller, no more than 2 sizes and retard your WOT timing two degrees per jet size. But fair warning, a lean outboard is a dead outboard. That modification might save you a gallon or two over the next year or two.

 

[linckeil]

Re: Re-Jetting for Economy

ok, the answer seems obvious. thanks guys.