Carb Heat Repairs

[Hank]

My carb heat cable seized and buckled, leaving carb heat about half on, carb temp ~40°C and climb rate miserable.

My new A&P got the cable working again, but it needs to be replaced. He says McFarlane doesn't do carb heat cables any more, although I'm quite puzzled about any difference between it and a throttle or mixture cable besides length, routing and what it's hooked up to.

Also need a new rod for the carb heat door to pivot around. She's flyable right now (picking her up tomorrow evening), but we have little confidence in how long it will last.

I'm open to suggestions for new carb heat cable and box . . .

[bonal]

Hank, get hold of Dan at LASAR they have a complete set of overhaul parts for the air box and they may have a replacement cable as well. Mine got a complete rebuild last annual. It was very sloppy. Now works very smoothly

There was also a detailed article on the rebuild that was featured on Mooney flyer earlier this year.

[Hank]

Thanks! I'll give them a call, and search the Flyer archives, if there is such a thing.

[bonal]

Wish I could remember what month buy pretty sure it was this year and yes they have archived each month. LASAR completely rebuilt the box with new everything it was 1.35 AMUs you might be able to get the parts and do the work yourself. I was a bit shocked by that one. But it turned out real nice.

[Andy95W]

It is true that McFarlane doesn't have a TSO'ed carb heat cable, but they have what you need. Give them a call and they will talk you and your A&P through the "owner produced part" rationale that make it legal. It sounds hinky, but yes, it is legal.

After that I would just pay your local A&P his hourly labor rate to do a field repair of your carb heat box using Acceptable Practices (ie., his common sense and good judgement).

[orionflt]

Hank,

When I needed to replace my carb heat cable I looked at a couple of owner produced options before going with the A-700 cable from Aircraft spruce  (http://www.aircraftspruce.com/catalog/appages/a700.php). as for the carb box, I had the same issues but luckily I have the resources to repair and or manufacture the parts i needed to make mine work properly. there is no rebuild kit, but if you take your old parts to a machine shop they should be able to help you out. if you still have issues let me know and I will see what I can do to help you.

 

Brian

[47U]

I vote with Bonal. Call Dan at LASAR. Mooney had a carb heat rebuild kit (600063-900 is the number in my logbook) that was a bit pricey at .8 AMU four years ago as I remember, but it includes a new flapper door, end bearing fittings to rivet into the box, and a new dump valve with the hardware bits and pieces. Also included was the blue-line drawing of the whole system. My flapper door shaft was shaped like a football and had wallered into the air intake plenum sheet metal. I made a patch and sealed it up with red RTV, but another A&P might have replaced the whole box, rightfully so. Labor is cheap when you're working for yourself so I had nothng to lose by screwing around with it for a couple days.

My carb heat cable was shot, too. The wire was worn about 70% through where it exits the sheath. I sent it over to Dan and his resources silver-soldered a new wire onto the knob just like new for around .1 AMU. It was a pretty quick turn around, too... a couple days, only. My first annual was a circus (jerk) and this is only one instance of several issues where LASAR, and Dan in particular, was a great resource to this new Mooney owner.

[Hank]

 

 

Thanks, ya'll. Annual is coming up next month. I will call McFarlane and get the new mechanic in the loop on "owner supplied" cable. My '70 model isn't a simple push-pull cable with a knob on the end; it's under the throttle quadrant, and the lever moves up and down.

 

I'll also call LASAR for current pricing and compare against the mechanic's best guess to rework the box, and jump whichever way is cheaper. The box and flapper both appear to be in good shape, the cable is not so swift but moving again. The cable attaches to the left side of the box, and the bearings and supports on that side are floppy loose and shot.

 

This will be owner-assisted annual number 8 for me, but so many of them include new work--wheel bearings, shock discs, tires, tubes, etc.

[bonal]

I stopped by LASAR yesterday to say hi and meet the new service manager he seems real nice at the time they were in the process of overhauling an air box I did not have time to make inquiries but I know they have all the parts and I know mine was fixed real well. My carb heat control is panel mounted and has a push button release.