Lycoming 320 starting procedure

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apg1387
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Lycoming 320 starting procedure

Post by apg1387 » Thu Sep 27, 2018 7:11 pm

So I got my first airboat, total noob to airboats but have been around boats my whole life. You guys are probably going to roast me for this but how do I start my 320? Is it fuel pump, ignition, mag, mag Or is it fuel pump, mag, ignition, mag? Still learning about mags. After its started can do you turn the fuel pump off or does it stay running.

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Slidin Gator
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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Thu Sep 27, 2018 8:17 pm

Welcome to the addiction! :toothy7: Lot's to learn.

I assume it is carbureted? I take it you have an electric fuel pump (mounted on top of or below the tank), but you likely also have a mechanical fuel pump mounted on the front accessory housing (see pic). The purpose of the electric fuel pump is to prime the system, but the mechanical should pull fuel through the electric once the engine is operating.

You also have 2 mags, the STBD side mag should be the "Impulse" mag that is used for starting, the right mag is typically not the impulse type. This is the aviation standard, but it might be different on yours depending on what the prior owners did. With both mags off (see safety info below), if you turn the prop by hand, you should hear a clicking sound every so often, that is the impulse activating. Figure out which mag is making the noise and which switch it is connected to. When operating, both mags should be timed together at 25 degrees BTDC. But, at low RPM during starting, the impulse mag has a spring system that holds the timing back to fire close to TDC for easier starting. Once running this system stops due to centrifugal weights and timing reverts to the 25 degrees advance.

If not installed, add a mixture adjustment cable before running, it is a safety feature, see below.

Procedure is:
- #1, always check that the prop is clear, no one behind boat, no dogs etc...!
- Mixture adjustment to full rich, normally push the cable knob down
- Electric fuel pump on, wait until you hear it load up (a few seconds).
- Hit starter button
- Turn on Impulse mag only
- Engine should start, if not repeat above but add a pump or two of the accelerator to feed some fuel
- Once running, turn on PORT mag
- Confirm oil pressure
- Turn off fuel pump
- Let engine idle and build some temp before putting the hammer down. Usually idle up after a few minutes of idle to build heat.

Safety
The magneto ignition is designed to fail in the running position, no one wants their plane to stop running in the air! To disable, the magneto P lead has to be grounded, this is what the mag switch does. In the run position, the switch is off, in the stop position the switch is on to connect the mag to grounded. This means that a bad wire, switch or ground connection can result in a live mag - the motor may start if turned over, all it takes is one bad mag ground (2 opportunities to fail in the ON position). It also means that when turning the prop by hand there the potential for the motor to spring to life! I have also had a situation where a tree branch broke a mag switch, same thing, I could not turn off the mag.

This is where the mixture adjustment comes in. Normal running is at full rich, but to shut down, do not turn off the mag switches, particularly when hot, the motor may run on. Pull the mixture knob to the lean position. Motor will still idle, give it several seconds and it will stumble, then press the gas and the motor will shut down due to insufficient fuel. Then turn off mag switches. Always leave the mixture in the lean position when off, it prevents run away in the event of a "Ghost" start.

Also, aviation carbs are designed to revert to Wide Open in the event of failure of the throttle return spring. I use 2 springs for this reason, inspect yours. In the event of a WOT runaway, the mixture adjustment is your savior.

If for some reason the mechanical pump fails, you can turn on the electric to feed the motor, but figure out why the failure occurred and resolve first, otherwise you will likely burn up the electric in short order too (hard lesson on my part).

Also consider dual start switches, one latching (or a key switch), the other momentary, so it takes 2 switches to fail to crank the starter.

Always turn off the main battery switch (big red Perko) or disconnect the battery, before entering the cage. Never turn the prop by hand unless ALL plug wires are pulled, or you are trying to hand start the motor and you are prepared for the result. Treat the prop like a loaded gun!

I probably missed some items on the safety list, there are a few threads on the board covering it in more detail, do some searches on "Airboat Safety." Others will probably add.

Stay safe, have fun. Don't be afraid to drive it like you stole it, these things are more likely to sink off plane.

Image
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Lycoming 320 starting procedure

Post by One Eyed Gator » Fri Sep 28, 2018 8:13 am

Look under aircraft power at the top, there is a operation manual and parts manual for that motor.

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Re: Lycoming 320 starting procedure

Post by apg1387 » Fri Sep 28, 2018 6:53 pm

Great post, thanks for the info!

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Re: Lycoming 320 starting procedure

Post by Waggs » Mon Oct 01, 2018 9:46 pm

The O320 H model uses a manual fuel pump that's toward the prop.

Just a heads up
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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Tue Oct 02, 2018 10:43 am

Thanks Waggs, that pic is from a O-320-B2B.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

apg1387
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Re: Lycoming 320 starting procedure

Post by apg1387 » Sun Oct 21, 2018 12:00 pm

Anyone have a good parts diagram of the marvel 4spa carb? The lean/rich knob seems pretty straight forward, my boat doesn't have one to speak of, i am assuming lean/rich is controlled by a little lever or actuating piece on the carb. Also do people run any kind of air filter on these engines? Mine is currently open, thats the way I bought it, seems sketchy. Appreciate all your help guys.

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sun Oct 21, 2018 12:17 pm

Ok so I found it, had to be the lever zip tied in the rich position. Next question is does anyone have a good picture of they rigged up a knob to it?

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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Sun Oct 21, 2018 3:07 pm

A filter does take away a little power, but once you put one on and see all the stuff the motor would be eating, you'll stick with a filter. It's a custom bracket, flat plate and 4 holes to match carb flange, then a tube with a ridge at end for a K&N style oiled filter.

Image


I am interested to see other pictures of mixture control cable set up's too, but here is what I have:

This is a carb mounted bracket on a O-320-B2B that we just bought recently. Note that the mixture control is tie wrapped to rich as purchased, funny how every boat/engine you buy has that feature!

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For another point of reference, here is the set up on my O540. There is a threaded boss on the oil pan on that motor, so I mounted a swivel bracket with a space off the boss. I was concerned about it getting loose, but no issue so far, red loctite helps I think.

Image
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Look at Aircraft Spruce, I like the button lock cables. They ship out of Georgia:
https://www.aircraftspruce.com/menus/ap/controls.html

Aircraft Specialties is another source, they are out of Texas, longer shipping to Fla.:
http://www.aircraft-specialties.com

You can get the filter kit (and all of the above and more) from Schmidt Aviation in Pompano, Fla, search "schmidt airboat store" on this site for more info: 954-782-2845 Email: schmidtairboats@yahoo.com
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sun Oct 21, 2018 3:50 pm

Thanks Slidin, going to get that bracket for the filter asap, some good news I got her running this afternoon and got the starting procedure down pat. One thing I noticed though, either I don't have a mechanical fuel pump or it failed. When I shut off the electric pump down in the tank it would quit within a minute or two of me flipping the switch. Going to call the guy I bought it from later and see what he says about it.

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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Sun Oct 21, 2018 5:53 pm

Post some pictures of your motor so we can figure out what motor you have please. Your mechanical fuel pump should be pretty obvious, in the location shown on the original picture, or on the side of the case towards the prop end (H models as Waggs noted). More than likely you have a failed fuel pump and it is either in the fuel lines (electric pushing through it) or bypassed but still there. But it could have been removed and blanked off too.

You don't have to have a mechanical pump, they will run just fine on a 5-7 PSI electric. But there is nothing more reliable than a mechanical fuel pump and they don't need any battery power to run. They do not offer a rebuild kit (that I am aware of) for the mechanical pumps and it's pretty good coin for a new one, so many folks just bypass them and go electric. If you do that, I highly recommend a spare electric on hand, plus a means to prime it up.

Your electric is submerged in the tank? That is certainly a reliable way to go, no suction issues!
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sat Nov 17, 2018 1:11 pm

Here are some pics of the motor. In the last one you can see a little grey blanking plate, i am thinking thats where the mechanical pump was...
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Re: Lycoming 320 starting procedure

Post by apg1387 » Tue Nov 20, 2018 2:07 pm

That was definitely where the mechanical pump was. What are the downsides to putting the mechanical pump back if any? I am considering putting a facet electric pump on there and carrying a Holly Might mite as a backup. Which model of the facet pump do you run on your 320 and do you think the Holly Might mite has enough flow and pressure at 7 psi 32 gph ? I think I have a Holly mighty mite on there now, I didn't get a good look because its mounted under the deck but that's what it felt like, small and plastic.

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Re: Lycoming 320 starting procedure

Post by GMAC 76 » Tue Nov 20, 2018 8:47 pm

FACET GOLD FLOW....3-5 PSI....34 GPH

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Re: Lycoming 320 starting procedure

Post by apg1387 » Tue Nov 20, 2018 9:31 pm

Thanks GMAC

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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Wed Nov 21, 2018 12:16 pm

I like mechanical as the primary. They are more reliable, more tolerant of contamination, and don’t have potential for electrical issues. Key advantage is they will pull a good suction so they can suck the tank dry to get every last drop.

Add electric for redundancy.

That Faucet has a built in, easy to clean suction screen. Connect inlet of Faucet direct to tank. Make a loop in the suction line to hold fuel for quick priming.

Feed outlet to a water separating filter and then into inlet of Mechanical. Use electric to prime the system on first start of the day and then leave it off the rest of the day.

One note, had dirt dobbers clog up vent line on me one time. When motor started to stumble I turned on electric without resolving. Destroyed both pumps and ended up with 5 gallon jug in back seat gravity feeding to get home. I now have vent screen and spare electric. Even an el cheapo spare will get you home. Pack it in vac seal bag or other waterproof bag.

https://www.amazon.com/Bang4buck-Univer ... +fuel+pump
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Lycoming 320 starting procedure

Post by jopete » Fri Nov 23, 2018 7:40 pm

I always ran a electric on my lycomings. a Carter brand. I hate electric fuel pumps. I run a 13$ manual fuel pump on my GPU. if I ever get another Lycoming, it will have a manual fuel pump.


anyway.... on a new boat I usually get a label machine and label all the switches and I put a red arrow on the mag switches and power switches so I can glance down and see they are in the right position before I try to start the engine. saves on battery life when u spin and spin with mags off trying to start!! lol

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sat Nov 24, 2018 6:41 pm

Yeah I need to label my switches. Thanks for all the input guys.

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Re: Lycoming 320 starting procedure

Post by SeatCover » Sat Nov 24, 2018 10:02 pm

Reorder your switches whichever way you please but always put the most important 3 to start or stop the motor (pump and mags) on the side you like best by FEEL and just remember what does what. I wouldn't want to be looking for tags on mag switches when my boat is stuck wide open...and it's no race boat.my mags are on the back of my box and it's pretty easy to remember where they are. :florida:
12' Cut Gilleo, Angle Valve 0-320, 72" Whisper Tip. Goes wherever I point it. :florida:

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sat Dec 08, 2018 1:54 pm

I was going to wire up an outboard style kill switch on the ignition, anyone have one? I have a very newbie question for you guys, i took a look at my alternator this morning and noticed the positive lead is disconnected. Does this wire normally run straight to the positive terminal on the battery? Hopefully thats a good guess, also hoping it still works. How would you guys test this thing? Normally I would just put a multimeter straight on the alternator terminals but thats not really an option with a direct drive airplane engine.
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Re: Lycoming 320 starting procedure

Post by SeatCover » Sat Dec 08, 2018 2:58 pm

You have a delco 1 wire alternator, I dont know exactly what whoever was thinking? If that red wire touches anything it will be bad news for the diodes in the alternator. Looks like the black wire is what goes to the hot wire on the starter, but looks a bit small for an alternator that puts out 70+ amps.and it looks like house wire, no good on something that vibrates a lot. Get rid of the red loose wire and replace the black one with something like 12 guage silver stranded and heat shrink everything.
12' Cut Gilleo, Angle Valve 0-320, 72" Whisper Tip. Goes wherever I point it. :florida:

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Re: Lycoming 320 starting procedure

Post by SeatCover » Sat Dec 08, 2018 3:01 pm

Hold up, I think you may have an alternator that needs to be excited, is there a hole on the back of alternator with a spade connector? I had a mud truck years ago that was like that. There should be 2 spade connectors in the housing, plug it in each one and check your battery volts while running vs off, u will see when it charges.
12' Cut Gilleo, Angle Valve 0-320, 72" Whisper Tip. Goes wherever I point it. :florida:

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Re: Lycoming 320 starting procedure

Post by apg1387 » Sat Dec 08, 2018 3:19 pm

Slidin, do you remember if you ordered the 5' or 8' cable with your button lock for the carb fuel mixture?

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Re: Lycoming 320 starting procedure

Post by Slidin Gator » Sat Dec 08, 2018 9:10 pm

I have an 8 foot cable on a front driver, 6 cylinder. The cable also runs from port side on engine to stbd side gauge/control box. You should make your own measurements for your boat, but better too long than too short.

Also, SeatCover is definitely right, all that wiring needs to be re-done, including the main power from battery to starter, that does not look right. The only wire that looks reasonable is the start wire from your starter switch to solenoid (the small wire on the starter).

SeatCover is also most likely right that you have a 3 wire alternator. But his recommendation to try either connector terminal until it works is not the best recommendation, it will overcharge the battery while running and drain the battery when off.

A 3 Wire Delco 10 or 12SI will have 2 spade terminals, shown as 1 & 2 on the case. A 1 wire alternator will not have the 2 spade terminals and it may or may not have a hole in the case or a rubber plug in that hole. This is a picture of the 3 wire:

Image

The "Bat" post is the power output to battery positive
Terminal #1 is the "Excitation Terminal".
Terminal #2 is the "Sense" terminal.

If you just connect T2-Sense to the Bat post the alternator will not (normally) excite and should not run.

If you only connect T1-Excite to Bat post the alternator will self excite and start. However, the sense terminal does not get any reference, more than likely reading low, in which case the Alternator thinks voltage is way low and goes to maximum output, which is where it will likely stay, even when the battery is fully charged, leading to over charging. When the motor is off, the excitation remains live, so the alternator drains the battery, unless isolated by a main battery shut off (Perko etc.).

At a minimum you should connect both T1 and T2 to the Bat post to excite and sense. The alternator will run, won't over charge, but will drain the battery when off. If the wiring from the Bat post back to the battery is poor, the alternator may not charge well. Both the barely hanging on black wire to starter, and start to battery wires look shot, I can believe the starter even works??

From the Bat Post to the Starter solenoid, you want #10 AWG wiring minimum. From the Starter solenoid to the battery main disconnect switch, you want #4 AWG minimum, but #2 AWG is highly recommended.

For the rest of the wiring, you can leave T2-Sense connected to Bat on the alternator, but it is better to run a #16 AWG or larger wire from T2 to the Main battery switch (Perko). This allows the alternator to best sense actual battery condition.

Next, T1-excitation needs to go to a switched source to simplify turning the alternator on and off. The simplest is to connect this to a main power switch that turns power on/off to the starter switch. With a good regulator, external excitation is only required momentarily such that T1 can be switched off (or left on) once the alternator starts. When the regulator fails, it is possible for the regulator excitation to short to ground, which will probably blow fuses or worse in the gauge panel. Normally the T1 line has the dashboard "Idiot" light that limits current in this line, I use a 40 ohm, 20 watt resistor in this line instead. Use #16 AWG or larger wire here.

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If the above is too complicated, then you probably need to get a 1 wire alternator.

Sorry, didn't get to the boat style kill switch question, that is really pretty involved in itself for a dual mag motor!

Here is a great link that discusses 1 wire vs. 3 wire alternator circuits.
http://madelectrical.com/electricaltech ... wire.shtml
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Lycoming 320 starting procedure

Post by Gary S » Sun Dec 09, 2018 7:17 am

I have a friend that has a rebuild shop and he always made a short jumper that connected terminals 1 and 2 together. You have to get on the gas a little to get it to start charging but no worse than putting boat on a plane. You will not have a drain on battery with this method.
I agree with the wiring. I personally would rather see #10 from alternator. Assar as what is going from starter to battery, it looks like a extension cord.

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