Starter/Ignition issues

[jfalisi201]

Advice wanted, I have a 78' M20J. Recently have had some starter problems. It was dragging like it had a dead spot, but it would eventually catch on and start. I replaced the starter relay and installed a new Sky-Tec 149NL with no change. I assume the only thing left is the ignition switch? Any suggestions on were to get one?

Thanks Jim

[larryb]

Battery?

[MooneyMitch]

Just a suggestion for you. Check the battery cable integrity, making sure there are no bare spots along its routing which could be shorting to the frame or engine mount. Do the same with ignition switch wires/solenoid cables/wires.

[laytonl]

Don't forget the master solenoid is in the circuit too. I suggest you start at the battery and check the voltage across each cable, the master solenoid, switch, and starter solenoid, while running the starter. You should find a large voltage drop somewhere. Lee

[danb35]

...and check grounds too. Same thing Lee suggested, measure voltage from the battery negative terminal to each grounding point while the engine is cranking. Small numbers good, big numbers bad.

[jfalisi201]

Thank you all, especially Lee and danb35, master solenoid it was. All is good.

Thanks for your help, Jim

[bd32322]

Don't forget the master solenoid is in the circuit too. I suggest you start at the battery and check the voltage across each cable, the master solenoid, switch, and starter solenoid, while running the starter. You should find a large voltage drop somewhere. Lee

I am having a similar issue, but i am an electrical newbie in possession of a multimeter. So if i understand you correctly, i should check the voltage drop across each of the items you mentioned, and a large drop would indicate a failed component correct?

Also if my battery reads 12.3 to 12.5, it should be okay correct? Or is there some other property of batteries other than voltage across terminals that determines how hard it can crank the engine? To isolate the battery as a problem on a 12 volt electrical system, i am wondering if i can jump the aircraft battery with my car and see if the sluggish cranking disappears....

Thanks in advance

[laytonl]

A fully charged battery should be at least 12.3-volts. However, the open-circuit voltage (ie. no load on the battery) can be deceiving. The voltage should stay above 12 volts with a significant load such as landing light and pitot heat.

As to trouble shooting, it probably makes more sense to check the voltage to ground at each component and a drop of more than 0.1 volts across any component may indiciate a problem.

Good luck,

Lee

[N201MKTurbo]

I had a similar problem once. It turned out to be a bad connection where the cross member that supports the battery was attached to the airframe. I kept getting low power starts, the starter would barely crank. I checked all over and finally found a voltage drop while cranking of ~2V between the battery negative terminal and the access door (airframe). I removed the four bolts holding the cross member to the airframe, cleaned everything up (all the surfaces were painted with chromate) and re-installed the hardware with just star washers so they would bite into the metal and make a good connection. Problem solved, it started perfectly.

[Lionudakis]

Some extra advice..... If it's cranking at all, it's not the ignition switch, If it's acting like the battery is low, it might be a weak battery, just because it is 12+ volts doesn't mean has the amperage available to crank the engine. Also the electron circuit needs to make a complete loop, the starter, starter relay, master relay, cables, connectors, power and grounds, or a combination of each can add up to a kink in the circuit. I've replaced many battery cables in various aircraft with excellent results, it's generally old wire, slightly oxidized/corroded under the insulation, with dirty / poor connectors, all add up to restrictions.

For testing batteries one of them cheap load testers from auto parts work well to keep tabs on the condition of your battery. The battery that starts struggling to crank the engine is well past it's capability of doing it's other job of supplying enough juice to get you to vfr or the ground in the event of a gen / alternator failure.

[N201MKTurbo]

The best way to check if the starter is getting enough juice is to measure the voltage at the starter while it is cranking. This requires you to put a meter lead on the actual starter terminal. This is done by attaching an alligator clip lead to the starter terminal and the other end to the meter. connect the other meter lead to the engine. On a 12 volt plane you should see greater then 10V at the starter while cranking, anything less and you have a problem. If you see more then 10V and the starter still does not crank well, then the starter is bad.

[bd32322]

The best way to check if the starter is getting enough juice is to measure the voltage at the starter while it is cranking. This requires you to put a meter lead on the actual starter terminal. This is done by attaching an alligator clip lead to the starter terminal and the other end to the meter. connect the other meter lead to the engine. On a 12 volt plane you should see greater then 10V at the starter while cranking, anything less and you have a problem. If you see more then 10V and the starter still does not crank well, then the starter is bad.

Good idea! I'll let you guys know after i do some troubleshooting this week.

[jimluper]

I have a 1975 M20E, does anyone know where I can buy a new Starter solenoid ?

 

Thanks

[isaacpr7]

I am having the same issue and the only thing that seems to work is to turn the sprocket a few turns on the starter manually with a long screw driver. After I do this, I can get a good start but it is getting very anoying.

[Marauder]

It sounds like there is a starter conspiracy going on! After fueling up after a trip, I could not get my starter to engage today. I've been having issues with the Bendix not engaging periodically. Usually after a couple of attempts it would. Not today

[Shadrach]

It sounds like there is a starter conspiracy going fan on! After fueling up after a trip, I could not get my starter to engage today. I've been having issues with the Bendix not engaging periodically. Usually after a couple of attempts it would. Not today

It sounds like there is a starter conspiracy going on! After fueling up after a trip, I could not get my starter to engage today. I've been having issues with the Bendix not engaging periodically. Usually after a couple of attempts it would. Not today

A little shot of silicon sometimes helps... I am not a fan of trying to service the starter while on the plane, but sometimes the bendix hangs up in cold weather.

[Marauder]

A little shot of silicon sometimes helps... I am not a fan of trying to service the starter while on the plane, but sometimes the bendix hangs up in cold weather.

I have been using silicon for the past 15 years on it. In fact, probably enough to take my wife from a B to a DD. I sprayed it again yesterday and will go out today to see if it will turn. I also threw my special battery charger (only special because it is specific to the Concorde and costs a lot) on it last night just in case flying 2 hours wasn't enough for the battery.

Pretty humbling to have the line boy tug me back from the pumps to my hangar...

[N201MKTurbo]

You can engage the bendix by rotating the bendix with a screwdriver or bic pen, while rotating the prop backwards. Once engaged you have one shot at starting the engine. Not something you want to do every day but it will get you home.

[Marauder]

You can engage the bendix by rotating the bendix with a screwdriver or bic pen, while rotating the prop backwards. Once engaged you have one shot at starting the engine. Not something you want to do every day but it will get you home.

I'm headed out to the airport to see if it will turn. If not, I will try your method. I am assuming that if I release the key on a non-start, I can repeat the process to try again? The Bendix should retract afterwards.

[N201MKTurbo]

I'm headed out to the airport to see if it will turn. If not, I will try your method. I am assuming that if I release the key on a non-start, I can repeat the process to try again? The Bendix should retract afterwards.

 

Yes when the engine fires it will force the bendix to retract.

 

This is easy to do on an F unless you have a cowl closure.

[N201MKTurbo]

BTW If you have a Prestolite starter, I have a perfectly functional one collecting dust in my hanger that I'll sell for less then the cost of a bendix..

[Marauder]

Yes when the engine fires it will force the bendix to retract.

This is easy to do on an F unless you have a cowl closure.

Oh you had to say the ugly words "cowl enclosure". I do have one.

[Marauder]

BTW If you have a Prestolite starter, I have a perfectly functional one collecting dust in my hanger that I'll sell for less then the cost of a bendix..

Thanks for the offer. Starter has been in there for quite a while, so I'm not sure what I have. Will determine and let you know.

[N201MKTurbo]

Oh you had to say the ugly words "cowl enclosure". I do have one.

 

You might still be able to do it, it'll just be a PITA.....

[Marauder]

You might still be able to do it, it'll just be a PITA.....

The only way I can get to that side of the starter would be to drop the cowling. I can't even see that side of the starter.