Hard start

[cdsracing]

I Have a 68C model and since I have taken a long trip I have had trouble starting, At first I thought it was my shower of sparks but now I think it is a fuel problem. It use to start with pump on and two pumps of the throttle after two rotations it was running now I cant seem to get it started unless while turning it over I pump the shit out of the throttle. has any one else had these problems ? 

[Hank]

That happened to me a couple of years ago, almost stranded me away from home once.

 

I did the following over several months; each helped for a little while:

 

-new plugs

-checked mags

-carb OH

-shower of sparks OH

 

Then she cranked well, and still does. The SoS was buzzing away, but apparently something inside it was working intermittently. We did the carb because, even with all of the throttle pumping, no fuel ever dripped out the cowl, so we thought it wasn't metering enough. Who ever heard of an engine that won't flood?

 

Good luck with your troubles. Let us know what fixes it.

[N33GG]

The old Mooneys have P Leads from the mags that have insulation that gets brittle a fails with time. Check where the wires from the mags pass through baffling and look for crumbling insulation.

Other than that, the ignition switch has a lot going on during start, and if worn can give problems.

You should consider getting your aircraft to someone that knows old Mooneys inside and out, like Don Maxwell.

I used to own a 68C, and speak from considerable experience. This can be very frustrating, and until you get it fixed right, you are playing Russian roulette with getting stranded.

FWIW YMMV

Good luck!

[bonal]

_{Lots of posts on the subject in fact my hard starting is what led me to Mooney Space. I would suspect an ignition issue if its cranking.  See if you are getting fuel to flow out after pressurizing and pumping. easy to check by looking into intake box for fuel. Shower of Sparks can be confirmed by listening for the buzz. +1 on the leads as they can fail as indicated above. Mine finally just refused to start one day and it was found to be a failed mag.  You can try getting the motor cranking then just release from start to both on the switch and if it catches then its likely your mag that has the starting circuit (cant remember which one it is)  Good luck,  I know how frustrating this can be.}

[Jerry 5TJ]

My 65C got harder to start one winter. I checked plugs, wires, fuel, mag timing, SoS. No improvement; still hard to start cold. Then the left mag failed completely. After rebuilding both mags the plane once again started easily.

[garytex]

Yes mags are something that we treat now like we treat modern ignitions, but they are not. Even on Bendix mags if you're more than 500 hrs passed a good Iran it's time. All us old farts can remember how much maintenance the old points and condenser ignitions used to take. That's what a magneto contains plus it's own little generator they just don't go past 500 very well

[jamesm]

You may want to verify mag timing to the Engine as well and others have stated check  the wire connections/terminations. Shower of sparks does timing but I could never find procedure to check and verify SOS timing.

What stater do you have ?

 

James  '67C 

[jwhitaker74]

 For Carb planes number one culprit i see is weak coils in magnetos and or timing has wandered. You can try running your plane to normal temp and bring rpm back to idle and if by going to one mag on switch it tries to die then its a good sign of weak coil.. There could be carb issue do a rich lean check by slowly retarding mixture when idling and you should see an rpm increase up to 100 rpm befor rpm declines then engine shuts down. If you dont get the increase then you can turn in idle mixture thumb screw 1/2 turn at a time and retry till it is right. Make sure your mixture cable and throttle cables move to both stops on carb as well. also theres a filter at the carb make sure its not dirty. Injected planes do same rich lean check and adjust linkage and inspect las chance filter in servo and mags.

[Shadrach]

My 65C got harder to start one winter. I checked plugs, wires, fuel, mag timing, SoS. No improvement; still hard to start cold. Then the left mag failed completely. After rebuilding both mags the plane once again started easily.

Yes mags are something that we treat now like we treat modern ignitions, but they are not. Even on Bendix mags if you're more than 500 hrs passed a good Iran it's time. All us old farts can remember how much maintenance the old points and condenser ignitions used to take. That's what a magneto contains plus it's own little generator they just don't go past 500 very well

In my experience, Bendix mags will run well within specs long past 500hrs. It's a good idea to check them out, but often times they need little more than a few minor adjustments. The few issues we've had have been more related to calendar time than tach time. On the factory engine that came with the aircraft, the bendix mags went 1850hrs and 37 yrs with out any major repairs or OH. We opened them at 500 and 750 alternated those schedules. I did have one coil failure on the right mag a few years back. The coil was well over 45 years old and ~2450 hours. The coil in the left mag is 48yrs old and has 2900hrs on it. Do you replace these pieces as a matter of principle?