Ignition Switch issue ?

[Green Hornet]

I have been encountering an issue when I hot start the aircraft. It is not the hot start process that is a problem. The engine will not turn over until I am about to give up as not to drain the battery. What I have noticed is when I relax the key from wall banging it starts. Now I have to catch it just right (just off the wall) an hold it long enough for the turn over but it starts. Is this indicative of an ignition switch problem about to happen? keep in mind this never happens on cold start. I have been using LOWFLYBYE'S technique discussed in previous thread for hot start that has been reliable. Any inputs are appreciated.

[a64pilot]

If when you turn the key, you hear a distinct click, then it's not the key switch, it's either the starter or the solenoid mounted on the firewall. To isolate if it's the key switch, it's very easily removed by unscrewing the ring on the outside of it. From there it would be very easy to jumper the wires that provide power to the starter solenoid. There are two other wires also, of course they are for grounding the mags.
If it's the solenoid, Maule buy's it from OMC, it's off of an evinrude outboard motor, the OMC part # is printed on it. Of course you have to buy it from Maule or it's not an FAA approved part.
If it is the part of the key switch that grounds the mags, that can be easily checked by disconnecting the mag wires. Then the mags will be hot all of the time, which is unsafe and you can't do a mag check, so if that's it order a new switch from aircraft spruce or elsewhere.

[Green Hornet]

A649 (what is your first name?)

As you suggested we did the following:

First we checked the continuity of the magneto P-leads to ground with the switch off. They should be grounded with the switch off and they were. (The P-lead is the connection that tells the magneto when it should be "hot" - if the P-lead is grounded then the mag is turned off...whereas if the P-lead is open then the mag is "hot".) Then we cycled the switch while looking at the left magneto P-lead. The P-lead should become ungrounded when the switch got to the L-Both-and Start positions. But instead the P-lead stayed at ground potential. We checked the R magneto and it also stayed grounded regardless of ignition switch position.

This was consistent with the no-cold start situation I had this afternoon...neither of the magnetos would come to life because the ignition switch kept both of their P-leads grounded.
We then pulled the ignition switch and disconnected it and after testing it again discovered that the L magneto's P-lead was always grounded (like we saw in the first test above) but the R magneto's P-lead would unground itself (like it is supposed to) but only some of the time. Also, even if the R magneto was properly ungrounded on the Both position if you turned the key farther to the Start position the P-lead would re-ground itself...thus preventing the engine from firing while the starter motor was engaged.

Ordered a new switch this afternoon. We plan to install Wednesday next week.
Once again thanks for sharing your knowledge. It is always nice to have someone as a go to answer man.
It is appreciated !
Bill

It is not your fault you got assigned to the 1St Cav and not the 101

[flyer]

Sojorn

Just to make sure everyone is on the same page. In the Start position, the right mag should be grounded and the left mag should be ungrounded.
The engine starts on the left mag only I think. Unless you have two impulse couplings.

flyer

[MauleMedic]

Ah, flyer, I think you might be right on that. It is common / especially on older aircraft with a separate starter switch (or when hand-propping) to start the engine on the L mag and then switch over to the Both position once it fires.

(Hence the common OFF-R-L-BOTH sequence - which, by the way, is why you always have to question the pilot twice when they have, say, a L-mag drop that's below limits ...verify with something like "just making sure it's the L mag and not the L position on the switch right?" can save a lot of tail-chasing.)

It could be, as you say, these newer ignition switches with the Start built in do that L to Both switching automatically - since you can't manually.

Having said that...it still doesn't help matters much when the Left mag's P-lead is always grounded!

[Green Hornet]

Flyer,
What Maule Medic said. He is my A & P and a good one

[flyer]

Sojoorn

I did not completely understand your description of your investigations.
Did you disconnect the left mag wire from the switch? Was the left mag then ungrounded? I was not clear if you did this.

Good luck

flyer

[a64pilot]

It's Joseph, but everyone calls me Jody. If you were Army, you know how that went
I was 6th Cav, not first Cav, but I would have been just as proud to have been "first team". If you were Aviation, and especially a Gun driver you understand the "Cav" mentality. It really was a little like Apocalypse now. Drove the regular Army nuts.
It is common for the mag without an impulse coupling to be grounded during starting to prevent kickback that would harm the starter. The impulse does two things, it retards the timing to TDC or there about for starting, and provides a "snap" that jumps up the voltage by delaying the mag and then releasing it, which makes more current because the mag moves much faster than the engine is at starting speeds. I believe starter switches usually have a jumper wire to ground the mag without an impulse or remove the jumper if both have an impulse. If allowed, making both have a starting impulse is a good thing to do, in my opinion.
If you have an IO-540 W1A5D, the D means dual mag, which is really a single mag, but either way I believe both fire on starting.
I'm not an "answer" man, I have little Maule knowledge. David Wright or Jeremy would I think be better sources, especially for Maule specific things. I know general aircraft, and well sometimes Maules are just different.

[Green Hornet]

It's Joseph, but everyone calls me Jody. If you were Army, you know how that went
I was 6th Cav, not first Cav, but I would have been just as proud to have been "first team". If you were Aviation, and especially a Gun driver you understand the "Cav" mentality. It really was a little like Apocalypse now. Drove the regular Army nuts.
It is common for the mag without an impulse coupling to be grounded during starting to prevent kickback that would harm the starter. The impulse does two things, it retards the timing to TDC or there about for starting, and provides a "snap" that jumps up the voltage by delaying the mag and then releasing it, which makes more current because the mag moves much faster than the engine is at starting speeds. I believe starter switches usually have a jumper wire to ground the mag without an impulse or remove the jumper if both have an impulse. If allowed, making both have a starting impulse is a good thing to do, in my opinion.
If you have an IO-540 W1A5D, the D means dual mag, which is really a single mag, but either way I believe both fire on starting.
I'm not an "answer" man, I have little Maule knowledge. David Wright or Jeremy would I think be better sources, especially for Maule specific things. I know general aircraft, and well sometimes Maules are just different.

Jody,
I wasn't a gun driver I was a door gunner on a slick. We actually hovered and landed in LZ's with nothing heavier than an M60. You keep saying "IF I was in the Army". You must meet a lot of wanabe's. " You had a good job but you left, sound off 123...
My entire time spent in Army Aviation was in RVN so not much time to interact with the rest of the army except grunts and that was brief in bound / out bound. Unlike Pilots, Door Gunners did not have mandatory ground time. Although if we meet at a fly in, over a beer I will tell you about my first ever stick time.

188th Aviation Company (Air Mobile Light), 101st Aviation Battalion, 101st Airborne Division, Fort Campbell, Kentucky - Dau Tieng, South Vietnam – III Corps Area of Operation (AO) (11/66-5/67).

188th Assault Helicopter Company “Black Widows”, 269th Combat Aviation Battalion “Black Barons”, 1st Aviation Brigade, call sign: “Hawk”, Dau Tieng (Camp Rainier), South Vietnam (5/67-3/68 Motto: “AIM HIGH”
This was Apocalypse now...

Did not mean to shine a light on you I was just real happy that I was right about the switch and FWIW your inputs are appreciated. I agree both David and Jeremy's help is also always knowledgeable & appreciated.

Flyer,
I will let the Maule medic tell you what he did I am forever on a learning curve. However he is taking finals for his Masters degree from Stanford University and quite busy. The only input I have is that switches have gone through changes over the years. Like I said I was just happy that it wasn't the Mags! ... I have a plan to have Maule Mods in Idaho put on Patroller doors and VG's in 2 weeks or so and I don't want Murphy to mess it up.

[aero101]

Interesting that we got so many EX-Crew Chiefs flying Maules? I was with "159th Dustoff" in that wonderful fun capital, RVN too... If we carried M60's had to do it on a bungee which was actually kinda fun!!! And yes, I remember my first 'Stick Time' too, thank god I had a lot of room!!!

[Green Hornet]

Hey Jim,
Anyone who can put the hours we did in the air and go into the places we went has to have the flying bug if he continues to volunteer. There were so many who quit flying after a short period on time. We did some dust off but I liked having the M60. I saw some of you guys go in to some hot LZ's with nothing but prayer. Here is a web site you might enjoy but I am not responsible for some of the content.

http://www.blackwidows.net/

Are you going to the Idaho flyin?
I am happy to here I am not the lone ranger. Who are the other crew members?
Clear Right
Bill

[Roy]

Hey Jim, I'm not trying to hijack this thread, because I have nothing to ad to the switch problem. However, I was also in the 101st airborne, 159th, 1968 and 69, camp Eagle in HC right next door to B Company, then moved into Phu Bai and C company moved in next door. And I own a elderly M4,210.
Just wondering when you were over there.
Have a great day, Roy

[Green Hornet]

Roy, No problem hijacking the thread the Ignition subject is on hold until I actually get the ignition and install.
I was mostly in the South in 68 but in 67 we were TDY to Tuy Hoa and got up to Phu Bai, Danang, & Dong Ha. The 188th became the C101 after I ETS. The 188th was based at LZ Salley 68-69 . The 188th formed up at Ft. Campbell in 66.and was attached to the 101st. I was with the 82nd at Bragg 65-66
Any way Welcome Home!
One of these days I am going to try to make to Moultrie. Maybe we could get together?
We could get Christine to put the RVN question to a separate thread to see how many of us there are out there? If you guys are curious?
Airborne!

[a64pilot]

If you head towards Moultrie, You need to stop by Americus Ga. Partially because it's close and where Lindburg learned to fly and mostly because the Airport manager and Ag pilot there was a crew chief in a LOSH in first Cav., and I think would enjoy the visit.

[Green Hornet]

Jody
Sounds like a plan and if your around I would like to stop by and say Howdy
First I get to do the Idaho training and then I will have start thinking about the South East.