McFarlane Throttle Cable Installation on Mooney Rocket

[Bill E]

I am seeking advice or knowledge on a problem I'm having with a replacement throttle cable on my 1979 Mooney M20K Rocket.  My mechanic replaced a throttle cable with a McFarlane replacement part.  At first, the idle was set a little high.  Aside from having to taxi using my brakes (Manifold Pressure would not go below 1070 with throttle pulled all the way back) the throttle seemed to operate normally.  I flew the plane at high power settings, manipulating the throttle several times (1.2 hrs @ 85% power) and landed the aircraft without any further issues.  The mechanic made an attempt to adjust the throttle cable to bring the idle speed within limits.  I then attempted to fly the aircraft again.  The idle was within limits but the upper limits fell short.  Upon advancing the throttle all the way forward on takeoff roll, the engine quit at approximately 32 inches of MP.  I aborted, taxied back and tried again with the same results -- engine quit at 32" MP.  There was still another inch (or so) of available travel in the throttle, but the engine wouldn't run in that final range while being advanced completely forward.  The engine simply bogged down and tried to die.  By pulling the throttle back, I am able to keep the engine from shutting completely down.  We tried it with the Low Fuel Boost pump on and it had very little improvement.  My full power throttle MP redlines around 38.5".  I climb at 35/25.  I was not able to achieve enough power to takeoff.  Does anyone have any idea on what I can do to make this new installation operate properly?  The Rocket engine is a TSIO-520 NB.

[Slick Nick]

Are you sure the replacement cable was correct? Start with the obvious things (like the cable) first. 

[wombat]

As far as I know, the idle speed should not be set by the throttle cable, it's set by a stop on the throttle body.  Your throttle cable should let you get all the way to that stop.

As for high power settings....   That really shouldn't be a factor of the throttle cable either. The throttle cable simply moves the throttle lever and the mixture, turbo, induction, and other stuff just do what they do.  

If the only change is the throttle cable, you have other extremely serious problems that I think you should get fixed before you attempt to fly that aircraft again.

 

 

My Rocket is a 231 conversion as well, I'm happy to share pictures and whatnot if you want.

[1980Mooney]

4 hours ago, Bill E said:

I am seeking advice or knowledge on a problem I'm having with a replacement throttle cable on my 1979 Mooney M20K Rocket.  My mechanic replaced a throttle cable with a McFarlane replacement part.  At first, the idle was set a little high.  Aside from having to taxi using my brakes (Manifold Pressure would not go below 1070 with throttle pulled all the way back) the throttle seemed to operate normally.  I flew the plane at high power settings, manipulating the throttle several times (1.2 hrs @ 85% power) and landed the aircraft without any further issues.  The mechanic made an attempt to adjust the throttle cable to bring the idle speed within limits.  I then attempted to fly the aircraft again.  The idle was within limits but the upper limits fell short.  Upon advancing the throttle all the way forward on takeoff roll, the engine quit at approximately 32 inches of MP.  I aborted, taxied back and tried again with the same results -- engine quit at 32" MP.  There was still another inch (or so) of available travel in the throttle, but the engine wouldn't run in that final range while being advanced completely forward.  The engine simply bogged down and tried to die.  By pulling the throttle back, I am able to keep the engine from shutting completely down.  We tried it with the Low Fuel Boost pump on and it had very little improvement.  My full power throttle MP redlines around 38.5".  I climb at 35/25.  I was not able to achieve enough power to takeoff.  Does anyone have any idea on what I can do to make this new installation operate properly?  The Rocket engine is a TSIO-520 NB.

 

2 hours ago, wombat said:

As far as I know, the idle speed should not be set by the throttle cable, it's set by a stop on the throttle body.  Your throttle cable should let you get all the way to that stop.

As for high power settings....   That really shouldn't be a factor of the throttle cable either. The throttle cable simply moves the throttle lever and the mixture, turbo, induction, and other stuff just do what they do.  

If the only change is the throttle cable, you have other extremely serious problems that I think you should get fixed before you attempt to fly that aircraft again.

 

 

My Rocket is a 231 conversion as well, I'm happy to share pictures and whatnot if you want.

Engine quitting with full throttle on take-off roll after your mechanic made all these adjustments?  I hate to ask but does he actually know anything about a Cont TSIO-520NB? This personally sound unsafe to me.  

Here is RAM's troubleshooting guide - they are the experts on that engine.  Rocket Engineering lifted the engine/prop combination from the Cessna 340.

Troubleshooting — RAM Aircraft, L.P.

He should be following Cont. Manual M-0 and SID-97 

Maintenance Manual

SID97-3E Teledyne Continental® Aircraft Engine - DocsLib