25hp chrysler ignition

[cobrakada]

just joined and I am kind of new to owning a boat. I bought a traveler with a 25hp chrysler outboard. it's not running but I think I have narrowed it down to the ignition coils are bad. Correct me if i'm wrong but I tested the coils with an ohmeter and I have a good reading when connected to both wires on the coil but when I test from ground wire to spark plug tower I get no reading at all. Also wanted to know if I should have power going to the coils with the key on or are they energized once the engine is turning over. It is a model 252ba with a magneto and coils under the flywheel. Appreciate any and all replys and great forum!!

 

[MickLovin]

These have a set of points check they are clean and have the right gap, just a question, why did you go for the coils first. You should have a low ohm reading on your coils. I am unsure what you mean by spark plug tower, but if you mean between ground and the High tension lead of the coil, you should have a over-scale reading or very high ohm reading from ground to the HT inner core. So sorry bit unsure what you mean by tower. The cranking of the motor generates the power to energise the spark plugs not the battery.
Could be a condensor problem or even just your points not gapped properly.

 

[jerryjerry05]

Outboard ignition . com has test procedures for your motor.

 

[cobrakada]

I am getting no spark on either cyl and watched a video on how to test your coils so thats what I did. Yes when I say tower I mean spark plug wire. But should I get some kind of reading when probing ground wire and spark plug wire?

 

[wickware]

You have some good Norden and Frank Questions. They will probably Jump in later or you might need to add Hello Norden and Frank to your title. Meanwhile you are getting some good info related to my 1970 35hp Chrysler that has a mag sys that does not need a battery in the sys to start and run. My only ignition problem since 1984-85 has been dirty points due to adding excessive oil to the wics. With fine emery cloth dressing and grit removed, they still perform like new.

My suggestions while the more experienced testing is suggested:

1. A good visual exam of the mag sys and ck for Ohm continuity of point’s contacts closing vs them looking closed.

2. If you have a local small engine shop, they might be able to test your coils/condensers vs throwing money at new parts. We had a tester in a small engine’s lab that would make a good coil fire a plug or spark testers. The same analyzer would test the condenser X specs.

Attached is my mag sys. I almost damaged a coil (showing) with a long bolt (pulling).

Good Luck!

 

[cobrakada]

So I picked up a couple coils from a local used dealer her(Edmonton Alberta Canada) I tested them by probing the ground wire and the spark plug wire and got a reading where as I don't get anything when I do the same to mine . However they are different as they came off of a 45hp model. So I'm pretty sure that this is my problem of getting no spark

 

[Frank Acampora]

Blue wire(s) supplies power to the positive terminals of the coils with the ignition key on and the points closed. There should be two separate feeds, one to each positive terminal. White connects negative terminals to ground through the closed points. When the points open current stops flowing, the magnetic field collapses, and a high voltage pulse is sent to the respective plugs.

There should be low resistance between the positive and negative terminals of each coil with all wires removed. There should be HIGH resistance between the negative terminals and the coil center tower. on the order of a couple of thousand ohms. If you show an open circuit, (infinite ohms) the secondary winding is broken and the coil is no good. If you show low ohms, it is grounded to the primary winding and again no good.

You must check to see that 1. there is indeed 12 volts going to each positive terminal, 2. the points are not corroded or dicked-up and will carry current., 3. The gaps are set to .020, and 4. the grounds are fully functional. be certain that the ignition switch has 12 volts on the "I" terminal with the key in on or start position. Also be certain that the red wire is delivering 12 volts to the ignition switch. Be certain there is a ground wire between the points carrier plate and the block. Never mind! I misread your post. You have magneto ignition. Points are still set to .020 There are two brown wires coming out from the carrier plate. these are the stop wires and should be connected to the blue and white terminals. At the switch they should be connected to the two "M" terminals. The magnets in the flywheel pass the iron core laminations and induce a current into the magneto coils.After the magnets pass the laminations, the induced current stops, the magnetic field collapses and that high voltage pulse generated goes to the plugs.

 

[cobrakada]

Thanks Frank I'm getting no reading on either one of these coils on my engine so I guess I'm in the market for a couple coils! Thanks again you've all been VERY helpful!!

 

[wickware]

Please share your final fix for the records. What year model is your 25hp? Is the mag similar or the same as my 35hp (a pic if possible)? I try to record the 35-55hp Chrysler info and would like to know if a 25hp is related for sharing purposes (I do have a Clymer Manuel). Thanks

 

[Nordin]

Reading your thread from top I figure out that your engine is manuel started with regular magneto ignition system. It has the coils, points and capacitors under the flywheel. Right?
These 25Hp engines was manufactured wiht two different ign.systems. 1. Magneto ign.system with coils under the flywheel and magnapull started. 2. Battery ign.system with coils mounted on top of the powerhead and electricstarted.

The magneto ign.system is selfenergnezing, when the flywheel turns the magnets in the flywheel generat a magnetfield in the ign.coils the time the points is closed. When the points open the magnetfield colapse and induce a spark at the plug.

SO First check the points and clean them with fine sandpaper and regap them to 020.
The ign.coils should have resistancereading as primeside groundwire to windingwire (connected to pointsterminal) about 0,3-0,8 Ohm, secondaryside groundwire to hightensionwire about 5,5-8 kOhm (prefix 1000, 5500-8000 Ohm).


Take a close look at the sping in the boot at hightensionwire. It should cut thrue the wire and it usually get rust.

Check the stopcircuit, the stopbutton is connected with a black or brown dualwire to each pointsterminal under the flywheel.

 

[cobrakada]

I'm not sure of the year of the motor but it is a model #252ba. It is an electric start but does have the coils under the flywheel like in the pictures sent from Wickware. I took the boot off of the one coil and it is actually not rusted at all. I'm still leaning towards these coils but maybe i'mm missing something. Like I said before I get a good reading on the primary side but no reading at all on the secondary side. Thanks again for all the help guys!!