I agree with Lynn.  This is a very good way to overcome and test for a “too lean” condition.  When you turn on the high boost, watch the fuel flow.  If fuel flow increases more than 3-4 gph and the condition does not improve, turn it off.  I also believe this is a good “test” procedure and not a band aid to be used to fly across country.

Craig Berland

Colyn,

Ralf did not say that this occurred on takeoff or at low altitude with low airspeed, so even if the engine ended up with an overly rich mixture and ceased running, just turn the boost pump off and revert to the previous fuel air mixture. With a bit of altitude and 160 to 180 knots I do not see how there could be any chance of fatalities resulting.

I have used this high boost pump procedure, with the resulting increase in fuel flow, to remedy increasing CHTs more than once.

Make sure it is the HIGH boost you turn on and not the low. In many cases turning on the LOW boost pump will cause a slight decrease in fuel flow and will compound the problem of CHT increasing because of too lean of a mixture to the cylinders involved.

Lynn