Aux pump micro switch on throttle linkage

SpeedUSAF

210E 1965 #21058698 with IO-520A

The microswitch assembly on the throttle linkage that controls the Aux fuel pump speed circuit has failed. This switch assembly was replaced less than a year ago. (100 hours tach).

All other portions of the aux fuel pump circuitry check ok.

My IA believes there may be either a Cessna kit or Service bulletin that addresses this switch, either removing or replacing it with something better. 

In my humble opinion, the switch installation was not well engineered and will probably continue to fail. Would like to find a better solution. Suggestions?

NOTE: I do not fly the plane unless I can turn on the Aux pump with the "High" side (red) panel switch, so I am effectively grounded until we can replace the throttle microswitch or find a better solution. Concur? 

planewrench

Generally i have seen switches in such ugly condition, surprised that they have not failed. I'd try one more making sure the ramp is just actuating, not slammin into the body. It does not take much . If not ramped, just make sure it is closing, not being bottomed out. carl

Joemcspeed

Definitely following this as I have recently purchased a 210E. I’m trying to figure out a wierd switch labeled “Fuel” under the console.

Can you please tell me if you start your plane with the aux pump on, and see any fuel flow as you push the throttle in? Maybe thats how you noticed the LO side of your fuel pump wasn’t working? Mine does not show any fuel flow and so I start the plane using 2 seconds of the HI fuel pump.

Thanks - Joe

planewrench

Joe, you need to see what the POH for your model/eng combo says. If you have a weird switch somewhere,,, find someone or yourself to track it down. There are different combos of pumps in 210's , and other for that fact. Get to the bottom of what you have and how it operates. Maint manual will have information too.

carl

Joemcspeed

Thanks Carl,

I’ll track it down. It’s certainly after market. Quick question though…. Do you see fuel flow indicated with the LO pump on and throttle in on the start?

Thanks

planewrench

I suspect you should see some flow on the FF gage, There are different outputs for pump all over the board, especially in the cessna lines. If you can start it on low for priming, you are getting enough. Hi pump constant use is ONLY for eng fuel pump fail.. will drown the engine in flight. See if your POH gives any hints. Keep in mind the FF gage is really just a pressure gage set up to indice a flow, its source is from the flow divider up on top of the engine. If you just see a bump in the needle on the low side, you are getting something, even if it may be below the range on the gage. Without seeing what you have, just a stab from memory.

Carl