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                           Commander-List Digest Archive
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                     Total Messages Posted Sun 06/18/06: 1
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Today's Message Index:
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     1. 08:17 PM - Re: EBay 680FL N4998E-SN1739-141  (BillLeff1@aol.com)
 
 
 
________________________________  Message 1  _____________________________________


Time: 08:17:14 PM PST US
From: BillLeff1@aol.com
Subject: Re: Commander-List: EBay 680FL N4998E-SN1739-141

--> Commander-List message posted by: BillLeff1@aol.com

I have worked on the Simmons injectors for many years. All Simmons  injectors 
come from overhaul set 10% richer than originally designed. This was  done to 
improve single engine performance along with adding the large intake  scoop.

When installing the injector many mechanics adjust the idle mixture to take  
out that 10% and they do it with the engine hot. The Simmons injector uses  
engine oil in its metering circuit to control fuel flow. So, if you adjust it to

 not run rich with the engine hot it will be too lean when the engine is cold 
or  the oil is not at normal operating temperature.

A properly adjusted engine will run ok at idle when cold but must be leaned  
for operation on the ground when the oil is warm.

In the air it takes nearly 300 pph in climb to keep the cylinders cool (215  
deg C max continuous - without hurting it) and 150 pph (25 gph) to make the  
cylinders last (Per Engine). Any less and you might as well carry extra  
cylinders with you.

By the way, there are long and short propellers. The short props were an  
attempt to increase cruise speed. this was done at the expense of take off and

climb, including single engine climb (this was not the best of ideas).

If you have a plane with small air scoops (ie 680FP or an 8000 lb.  
680FL)this rich running problem is worse because you have more fuel and less  air.

Bill Leff