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Help with Onan magneto.


Hi everyone. I've been offered an incomplete Onan Model 305ACK, and I would like to know what...

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  #1  
Old 05-24-2007, 03:22 PM
twyford rich twyford rich is offline
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Question Help with Onan magneto.

Hi everyone.
I've been offered an incomplete Onan Model 305ACK, and I would like to know what magneto I will need for it to get it running. If I can pick one up reasonably priced then I would think about buying it, the full details are as follows:
Onan aircooled twin cylinder,
Model 305 ACK,
spec. no.99E/2254E,
ser. no. 101C666579,

Generator data; 305CK/286,
Battery 24volt,
AC volts 115 ph1,
Kva 3.5 Watts 3500,
DCvolts 30 amps 50 Watts1500

If anyone can help with a parts manual/instruction book or just tell me the make and type of magneto I need, I would be much obliged.

Many Thanks In advance.
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Old 05-25-2007, 07:09 PM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Help with Onan magneto.

I will check the files and see what mag it takes.
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Old 05-26-2007, 05:36 AM
twyford rich twyford rich is offline
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Default Re: Help with Onan magneto.

If its of any help the set is a military version.
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Old 03-27-2008, 07:03 AM
twyford rich twyford rich is offline
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Default Re: Help with Onan magneto.

Quote:
Originally Posted by twyford rich View Post
Hi everyone.
I've been offered an incomplete Onan Model 305ACK, and I would like to know what magneto I will need for it to get it running. If I can pick one up reasonably priced then I would think about buying it, the full details are as follows:
Onan aircooled twin cylinder,
Model 305 ACK,
spec. no.99E/2254E,
ser. no. 101C666597,

Generator data; 305CK/286,
Battery 24volt,
AC volts 115 ph1,
Kva 3.5 Watts 3500,
DCvolts 30 amps 50 Watts1500

If anyone can help with a parts manual/instruction book or just tell me the make and type of magneto I need, I would be much obliged.

Many Thanks In advance.
Greetings Again.
The above engine is now in my grubby little hands.

I have got more info on this engine now, it was used in/on the 'Honest John' missile system from the 60's to the 80's when the missiles were taken out of service, it's service designation was/is "Generator Set M25"
New numbers are,
Stock No.FSN 1055-385-8025
Contract No. DA-11-199-ORD-620

If anyone can help decypher the fsn and contract no, or point me in the direction of where I can get the info needed, I would be most grateful.

I will try and post a couple of pics of the engine at some stage if that helps as well.

Many thanks.
Twyford Rich
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Old 11-20-2008, 12:17 PM
KidDynamo KidDynamo is offline
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Default Re: Help with Onan magneto.

Did you ever find the magneto number? I have an Onan 3ACK that I will check its mag number.

Different unit, though but maybe the mag numbers from mine will help. I have a feeling that a lot of their units used the same magneto.

(See earlier post of mine. Mine is a twin cylinder Onan.)

http://www.smokstak.com/forum/showthread.php?t=54068
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Old 11-20-2008, 12:33 PM
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Default Re: Help with Onan magneto.

Are these the CCK units that were on ebay?

We bought one of the recon units, but there are also AJ and another unit, 6kVA or so that I have seen.

Peter
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Old 01-23-2009, 03:00 PM
twyford rich twyford rich is offline
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Default Re: Help with Onan magneto.

Hi all.

Been away from the stationary engine scene for a while, work commitments, trying to get a workshop set up and the cost of petrol (gasoline) put paid to that last year.

The answer is a resounding no, to getting the engine up and running, whilst its not running it doen't cost anything on petrol and oil. I did make contact with a guy from the 'Royal Artillery Musuem' in Greenwich (UK) and they have the 'Honest John' missile launcher with the tackle that used to run it, so I must take a visit to it and see what happens.

Rich
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Old 01-24-2009, 11:25 AM
Patrick Patrick is offline
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Default Re: Help with Onan magneto.

I doubt they ever even start theirs - maybe you could "swap" a few parts and keep it cosmetically the same! Unofficially, of course...
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Old 01-24-2009, 02:42 PM
VaughnSimon VaughnSimon is offline
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Default Re: Help with Onan magneto.

Just to take the conversation afield a bit... why do you really need a magneto?

Assuming that it has a standard CCK block and cam, could you put a points box on it? For sure you could install a Pertronix ignition as long as there is some rotating part available to stick a magnet to.

Vaughn
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Old 01-24-2009, 02:58 PM
flyag1 flyag1 is offline
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Default Re: ELECTRONIC IGNITIONS

Go here and scroll down the page about 1/2 way... Great Stuff and you get rid of that oil leaking points tower...

http://gmcmotorhome.info/generator.html
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Old 01-25-2009, 02:32 PM
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Default Re: Help with Onan magneto.

I am not sure the mag blocks were drilled for a point box. Be nice if it is.
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Old 01-25-2009, 04:35 PM
KidDynamo KidDynamo is offline
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Default Re: Help with Onan magneto.

The reason to go with a magneto is that they have such a hot spark when working properly! Maybe on an electric start unit this is less important.

On my manual start unit, a fantastic, hot magneto makes starting a breeze. Since my unit has no battery or provision for one, the mag is pretty much mandatory. I prefer magneto ignition and am always interested in generators which can be used without a battery so that I minimize the number of batteries around the house.


The weather finally allowed me to uncover my genset that may be similar to your's. I gassed it up, primed the carb, choked it, and it started right up with the pullstart. I ran it long enough to warm it up on a small load and while at it, I noted the magneto numbers.

It has a shielded magneto and wire system, barely visible in the first picture in my link. The mag is "on it's side" as mounted. I am using regular, unshielded sparkplugs with the bare ends of the shielded ignition wires just looped over the plug terminals, so don't let the odd looking plug wires confuse. (The shielded plugs are shorted & awaiting cleaning)

The magneto is:

Fairbanks Morse CCW (counter-clockwise) Type 5
FM PE1-2B69

There may be other magnetos that would fit up but I don't have spec's on the lag angle, etc. If you know that and know what type of drive coupling is used, you might be able to find a "civilian" mag that would work.

That is a lot easier to do in the states than in the UK, most likely. Hope this helps or at least keeps things rolling a bit.

http://www.smokstak.com/forum/showth...onan+generator
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Old 01-25-2009, 05:38 PM
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Default Re: Help with Onan magneto.

Go to the thread I posted and look at what they are doing. Drilling a hole in the blower / flywheel and gluing in a magnet, mounting the sensor on the back plate and hooking up the leads. All the electronic module does is to time the spark.... that's it. The same is true of the current points setup on my CCK… points time the spark from the coil. The coil then delivers the voltage to the spark plug.


I have flown for years behind 450 and 600 hp radials and opposed 4, 6, and 8 cyl air cooled engines. (Over 25,000 hrs of PIC) All running duel magnetos and dual spark plugs. In those hours I have experienced no less than 3 forced landings due to mag failure. I have driven for many more years than I have flown and in all the miles I have experienced 1 distributor failure. (1984 Chevy 350) However the FAA will not allow certified aircraft to run modern day ignition systems as they fear an alternator failure may force a landing. Like a magneto failure will not?

IMHO: there is only one benefit to running a magneto... (No battery or charging system required) There is no magneto made that can match the voltage (spark) provided by a late model ignition system.

If you have a charging system and battery a modern day electronic ignition system is a much superior system to the your current points system, as is the points system superior to the magneto. Oh, and no one says you have to buy onan specified coils or plugs. Plugs selection should be based on compression and operating temps as well as the voltage supplied by the coil. Google is your friend here… You want more SPARK=power to the plug change the coil to a higher output and then match the plug to the coil. The higher voltage ignition systems burn the fuel air mixture faster and more thoroughly which results in more power, less fuel consumption, and fewer emissions. Oh did I mention the electronic system will run in rain... don't get your points system wet

Want to get real hot sparks which will allow you to increase fuel air mixture beyond 40:1? Then do a search on plasma spark plugs. There are some boys out there using high voltage sparks… (120V & 240V). They piggyback a high voltage lead on the business end of the plug and when the low voltage (20,000V DC) jumps the gap it will take the high voltage with it and you have plasma in the cylinder. (Lightening Strikes) Look around on youtube and you will see some systems so hot they are burning water…

You are not limited to what you can do with these engines...unless you want to preserve a vintage unit and keep it original. However if you are like myself and looking for dependability then there are many modifications available that will help.

So out with the points, out with the control boards, in with electronic timing modules, and in with relays.

Dale
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