Heater vibrates closed

bryanflood · #1 05-16-2009, 10:51 PM

I have a stock RA-9A with a per plans Van's heater box set-up, the one with the push pull cable on the cabin side of the firewall. My problem is that the stock Vans detent cable seems to often vibrate closed. I have used various stop-gap measures in the past to rectify this problem such as a clothes pin between the knob and the panel on the heater cable to keep it open. Last winter however my clothes pin was lost on a trip. I resorted to using a small piece of duct tape to hold the knob in the open position for the flight home.

Now I am looking for a more permanent solution. Has anyone else had this problem and solved it? If so please share the solution.

Thanks,

Bryan

Harold Lanfear · #2 05-17-2009, 05:35 AM

with the Carb Heat cable on my Kitfox. After much playing around with different 'fixes', I pushed the knob fully "in" and put about a 15-20 degree bend in the wire by hand. When the knob is pulled out, the kink rubs on the metal sheath with enough friction to hold it in place, but does not bind.

Hope this helps, H

sprucemoose · #3 05-17-2009, 09:25 AM

I had the same problem with my carb heat cable. ACS sells a push-button locking cable with the same wire and shield size as the stock Van's cable. Replacing it was about a 20 minute job. Highly recommended.

kevinh · #4 05-17-2009, 10:18 AM

Quote:

Originally Posted by Harold Lanfear

with the Carb Heat cable on my Kitfox. After much playing around with different 'fixes', I pushed the knob fully "in" and put about a 15-20 degree bend in the wire by hand. When the knob is pulled out, the kink rubs on the metal sheath with enough friction to hold it in place, but does not bind.

I don't have this problem, but I'll definitely try to remember your fix. A very clever idea!

gasman · #5 05-17-2009, 11:44 AM

Quote:

Originally Posted by sprucemoose

I had the same problem with my carb heat cable. ACS sells a push-button locking cable with the same wire and shield size as the stock Van's cable. Replacing it was about a 20 minute job. Highly recommended.

NAPA AUTO PARTS has the same cable. twist lock.

chaskuss · #6 05-17-2009, 04:16 PM

Quote:

Originally Posted by gasman

NAPA AUTO PARTS has the same cable. twist lock.

Warren,
Can you provide a part number for the NAPA cable? If not a part number, what is this cable used for?
Charlie Kuss

sprucemoose · #7 05-17-2009, 05:48 PM

Quote:

Originally Posted by gasman

NAPA AUTO PARTS has the same cable. twist lock.

Good point. I don't like twist locks in this application (too close to the mixture knob) but this is a personal preference thing. The push button does work really slick, just like a vernier control cable (without the rotating feature of course.)

Any sort of locking handle is a big improvement over the stock setup.

Capflyer · #8 05-17-2009, 07:51 PM

I found a not necessarily permanent solution that for two winters has worked great. I split a piece of clear tubing the same length as the open valve and simply push it over the pulled cable and it holds well without looking like ****. Easy on/off and I store the piece of tubing in my kneeboard pocket.

gasman · #9 05-18-2009, 02:44 AM

Quote:

Originally Posted by chaskuss

Warren,
Can you provide a part number for the NAPA cable? If not a part number, what is this cable used for?
Charlie Kuss

NAPA....
731-1103 And you can change the knob. It has a set screw. They have them at Radio Shack. The cable slides in and out and then you just turn it 1/8 turn clockwise to friction lock it.

Steve Brown · #10 05-18-2009, 05:48 AM

Quote:

Originally Posted by bryanflood

Now I am looking for a more permanent solution. Has anyone else had this problem and solved it? If so please share the solution.

Thanks,

Bryan

I posted this last week:
"The arm that hooks to the door on mine has two holes. Originally my cable was hooked to the hole closest to the pivot point. So, leverage from the cable pulling on the door was low, but leverage from the door pulling on the cable was high.

I moved it to the other hole to reverse that situation.

I had to replace the cable with a longer one because the total movement is significantly more that before. Also, the cable pulls out slightly past the last detent.

Now the carb heat will not slip back in, even at cruise speed. Opening and closing is easier than before.

At some point I might modify the arm to have a location just slightly closer to the pivot point, but for now its fine."

Flew it again this week and it still seems to work fine.