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-   -   Cylinder 4 High EGT/CHT on Ground (https://vansairforce.net/community/showthread.php?t=171445)

Carl Froehlich 05-12-2019 11:54 AM

Quote:

Originally Posted by Nova RV (Post 1345990)

For a quick check of just the spider, you can disconnect the line at the injector (leave injectors installed) and put a shot glass under each disconnected line.

Carl

DanH 05-12-2019 12:57 PM

Quote:

Originally Posted by bsvantho (Post 1345951)
Makes sense - will try that per the AFP manual.

Just out of curiosity did you see any issue while at cruise power?

Above 6~7 GPH, flow division is function of nozzle restrictor size. At that point the piston in the flow divider is raised enough to uncover high volume ports, allowing fuel to bypass the metering slots. Those slots control division at low flow rates. As noted, the slot feeding #4 probably has some trash in it. So lean cylinder when at 3 GPH (slot blocked), normal at 19 GPH (blocked slot bypassed).

Photos and illustrations pages 16 and 17 here:

https://www.danhorton.net/Articles/B...yond%20(1).pdf

bsvantho 05-12-2019 05:40 PM

Quote:

Originally Posted by DanH (Post 1346019)
Above 6~7 GPH, flow division is function of nozzle restrictor size. At that point the piston in the flow divider is raised enough to uncover high volume ports, allowing fuel to bypass the metering slots. Those slots control division at low flow rates. As noted, the slot feeding #4 probably has some trash in it. So lean cylinder when at 3 GPH (slot blocked), normal at 19 GPH (blocked slot bypassed).

Photos and illustrations pages 16 and 17 here:

https://www.danhorton.net/Articles/B...yond%20(1).pdf

Did the shot glass test and sure enough almost nothing from No. 4 direct from the flow divider. The slot was restricted with a nearly invisible piece of debris. I am now intimitately familiar with the mechanics and geometry of the flow divider. It was a good learning experience. Did a run up, all is well after the cleaning.


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