Hard starting 67 M20F

[OR75]

I stand corrected. Throttle open and mixture cut off indeed.

[FloridaMan]

Get a SlickStart system and call it a day. You will never have an issue starting your airplane if your mags are working and you have one of those modules installed. 

 

You don't want to be taking an apprehensive passenger somewhere and have your airplane fail to start like it's a mid-70s domestic car. 

[Tmarsha]

I'm not familiar with the slick start system? I will google it and see what comes up. Any info is appreciated.

[FloridaMan]

The previous owner of my 67F had it installed when he started having trouble starting it. While the starter is engaged, it sends a "shower of sparks" to the plugs. Even when hot, if I prime (flood) the engine and hold the starter in, I'll get ignition and the engine will start. 

[Lood]

I must add that any of the newer, light weight/ high speed starters makes starting under all condition a lot easier than the old stock starter.

[OR75]

I must add that any of the newer, light weight/ high speed starters makes starting under all condition a lot easier than the old stock starter.

 

Do you have an idea of how much  faster the high speed starters spin the prop ?

 

Also, I believe with those high speed starters, you can only  crank for 10 seconds or less 6 times with 30 seconds in between each crank.

If it does not start, then you have to wait 30 minutes.

 

Do you ever get to that ?

 

 

Withe stock starter, some hot starts have been a pain, but it always start   

[1964-M20E]

All I know is once I had the skytek on my E model it started much better.  I have a high speed starter on my current F and I've only had one instance where a hot start got me.

[Lood]

Do you have an idea of how much  faster the high speed starters spin the prop ?

 

Also, I believe with those high speed starters, you can only  crank for 10 seconds or less 6 times with 30 seconds in between each crank.

If it does not start, then you have to wait 30 minutes.

 

Do you ever get to that ?

 

 

Withe stock starter, some hot starts have been a pain, but it always start   

 

I use to have a Skytek and I now have B&C. I can't say how much faster they spin, but it it substantial and it makes a huge difference when doing a hot start. With regards to the cranking time and intervals in between, I can't help, as I've never had to try twice, but if the engine takes longer than 10 seconds, something isn't right, I'd say. I did miss a couple of hot starts while I still had the Skytek and I would normally wait about a minute before trying again.

I stand to be corrected, but I do think these high speed starters draw more current and I don't think you'll get much more than three longish cranks out of the battery.

I must agree that although the original old bendix starters are heavy and slow, they are bullet proof and can be cranked almost all day.

[craigsteffen]

I bought my 1967 F model this last November, so I don't have a tremendous amount of experience with it.  It's the only plane I've flown for any amount with fuel injection; basically all my previous experience was with carbureted engines.

 

No matter the engine state or the technique I use, I've found that the throttle position at 1000 or 1200 rpm isn't enough to really get the engine going; it feels like it's struggling.  I always end up goosing the throttle to bring the rpm up to like 1500 and then settle it back down to 1000. 

 

For cold start, I use the technique that the former owner showed me:

Throttle set (I put it 1/3 of the way in)

mixure rich and leave it there. 

fuel pump on just until it stops rising, then off

IMMEDIATELY crank the engine

 

This works really really well for me.  It starts right away, after maybe one revolution.

 

For hot starts, I use the same technique that others use, to leave things mostly the same as shutdown (including mixture all the way out), except as I said, I have the throttle quite a bit higher.  It takes about 5 seconds of cranking and then it catches.  If I leave the throttle at 1200 or so, when it catches, I have to fight to get the mixture in and pick up the throttle before it dies.  If the throttle is higher, then I have plenty of time to get the mixture in and then grab the throttle and settle the engine down to a nice idle. 

 

Until I got the hot start figured out, I always had to crank twice when it was warm (one time three times).  I always cranked less than 10 seconds per try.  I figured something was wrong if it didn't start by then.  I do suspect that I have one of the new high-speed starters, it cranks over pretty fast.  When cranking, the engine does develop significant fuel pressure, not quite up to the green, but most of the way there. 

 

Craig Steffen

[craigsteffen]

The previous owner of my 67F had it installed when he started having trouble starting it. While the starter is engaged, it sends a "shower of sparks" to the plugs. Even when hot, if I prime (flood) the engine and hold the starter in, I'll get ignition and the engine will start. 

 

I don't know which models of Mooney have them, but mine definitely does.  Any Mooney with an IO-360-A1A has the "shower of sparks" system which goes with the retard left magneto (as opposed to impulse-coupled).  The POH refers to a shower of sparks.  Personally, I think "shower of sparks" is a bad name.  Another word for it is "vibrator"; when you put voltage on it, it switches its output on and off very quickly which pulses voltage down the line to the magneto.  Each off pulse fires the secondary coil in the magneto sending a spark to the spark plug, so instead of one spark per compression stroke while you have the starter in, you get dozens of sparks per compression. 

 

The original shower of sparks is electromechanical.  It's basically a heavy-duty relay with voltage across the coil wired so that as soon as the relay makes contact it disconnects the coil, so it bangs back and forth.  It sounds like the SlickStart system replaces the electromechanical vibrator with an electronic solid state one.  That means that it can put more than 12 volts to the magneto coil which might well result in a hotter spark.  I guess that could ignite fuel mixures over a wider range giving you a more reliable start. 

 

It would appear that the current Slickstart system is ONLY available for Slick magnetos, not Bendix. 

http://www.aircraftspruce.com/catalog/eppages/slickstart.php

http://www.matronics.com/forums/viewtopic.php?t=39132&sid=42e122bf1495ae5a8d84764eac248cc2

 

Craig Steffen