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Stator Coil Testing

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wayneakp

Member
Hi all
I have a Japanese built Mariner 30E -1999. Serial no ON002393. I wish to check the stator coil is good - is there a way to do that with a mulitimeter?

Thanks

Wayne
 
Thanks for that - I looked on their site earlier and they said "Except Japanese" - I am probably being thick so sorry but what am I looking for?

thanks

Wayne
 
you have a yamaha built engine which probably is a copy of one of their older models...i am not familiar with them and have no idea which year and model your motor is a copy of...

i sent a message to someone who may can help you and asked him to look at this thread..
 
papyson said:
you have a yamaha built engine which probably is a copy of one of their older models...i am not familiar with them and have no idea which year and model your motor is a copy of...

i sent a message to someone who may can help you and asked him to look at this thread..
Click to expand...

Much appreciated - thank you
 
I am the one he contacted because I do have some experience with the Japanese built portables.

Unfortunately, yours is not one of them - it's too new.

Yamaha built the Mariner line up until about 1992. They were simply a re-branded Yamaha mechanically identical to their (earlier) Yamaha counterpart.

I do have all the specs, test procedures etc for those.

Your being a 99 model, with the serial number noted is NOT (as far as I know), a Yamaha built model.

I do not know first hand for sure but believe that it was built by Tohatsu. They did build the 25 Merc 2 stroke for a few years (for international sales) and I have seen those motors but the Mariner Line (post Yamaha build days) was pretty much a European thing. The Mariners just sold better in Europe and they kept painting them that way long after they were no longer routinely carried at North American shops.

There is a couple of dealers/shop owners on here who can maybe point you in the direction of a shop manual, who built it (??), or who to contact.

I'm sorry, but I have no experience with these later Mariner models that are not "old Yami's".
 
bilge rat jim said:
I believe your outboard has a standard Mercury electrical system, and has a 832075A21 stator that was used by Merc on most outboards from 30-125 hp. Use this link to CDIs' troubleshhoting guide- the resistance values for your stator should be on page 77.

http://issuu.com/cdielectronics/docs/practical_ouboard_ignition_troubles
Click to expand...

Thanks everyone for your help. I pulled the flywheel off and the part no on the stator doesn't match the parts list / previous replies. The number on the coli is 1628C8 - so I am not even sure its the correct coil for the motor, or its just a number thing???

The part list is http://www.marineengine.com/parts/m...01875-thru-0n055504-bel/electrical-components

many thanks

Wayne
 
There is a video on YouTube titled "How to test a coil in an antique outboard engine" by Doug Penn. I watched it several times and then bought a multimeter at Menards that has a X1K setting for ohms. You place one probe anywhere on a grounded surface and the other probe inside the spark plug wire socket and the needle should drop from infinity down to 1 to 10 ohms. One note, one of my coils read 18 ohms, and the other read 10 so i assumed one of them might need to be replaced. (my motor is a 1967 Merc 9.8 hp). Anyway I ordered 2 new coils since they were 47 years old. When they arrived I checked them both with the multimeter and got 10 ohms on each coil. The coil that read 18 ohms was probably fine, but I'm not an electrician. Basically this is just checking for decent continuity. [h=1][/h][h=1][/h]
 
lightfoot1 said:
There is a video on YouTube titled "How to test a coil in an antique outboard engine" by Doug Penn. I watched it several times and then bought a multimeter at Menards that has a X1K setting for ohms. You place one probe anywhere on a grounded surface and the other probe inside the spark plug wire socket and the needle should drop from infinity down to 1 to 10 ohms. One note, one of my coils read 18 ohms, and the other read 10 so i assumed one of them might need to be replaced. (my motor is a 1967 Merc 9.8 hp). Anyway I ordered 2 new coils since they were 47 years old. When they arrived I checked them both with the multimeter and got 10 ohms on each coil. The coil that read 18 ohms was probably fine, but I'm not an electrician. Basically this is just checking for decent continuity.
Click to expand...


Thanks for your reply - although its actually the stator coil I would like to check. thanks

Wayne
 
This looks like a typical (later) generation of a Japanese outboard ignition system.

The coil with the yellow wires is referred to as the charge or lighting coil - goes to the rectifier or regulator to provide power/charge the battery.

The other coil is what (I know as) the "exciter" coil - which is what supplies the power to the coils and ultimately the sparkplugs.

On earlier systems of this style there would have been a third component called a "pulsar coil" and would have been mounted to the left of the shaft (where those threaded holes are between the two coils) which would have provided the "trigger" (the pulsar replaced the points on even earlier designs).

Looking at the parts list for this model, which you will find listed as a 30 hp 2 cylinder "International" on the Merc lists, there is no pulsar anymore, so I will assume, as Jeff suggests, that advancing/retarding of the entire plate occurs and the trigger is also a function of the exciter coil (so serves double duty).

Logic would state that the black wire is simply a ground and should be grounded against the block at any suitable point (but there would have been a post/screw for it from factory). It would ensure that the circuit is grounded and "could" be your issue if you have intermittent/no/weak spark.
 
Although having the resistance spec the coil is one check, you will also want to check the peak voltage it is producing and to do this you will need either a multimeter with a built in DVA or a separate adapter. Buying an adapter can be quite pricey but fortunately they are very easy to make. Here is a video of me making mine: https://youtu.be/juhri_NxQcQ

I'll be doing a video very soon on using it to perform the exact test you are talking about.

Stuart
 
DangarStu said:
Although having the resistance spec the coil is one check, you will also want to check the peak voltage it is producing and to do this you will need either a multimeter with a built in DVA or a separate adapter. Buying an adapter can be quite pricey but fortunately they are very easy to make. Here is a video of me making mine: https://youtu.be/juhri_NxQcQ

I'll be doing a video very soon on using it to perform the exact test you are talking about.

Stuart
Click to expand...

Thats great thanks - will get the DVA built and look forward to the diagnostic video

Cheers

Wayne
 
wayneakp said:
Thats great thanks - will get the DVA built and look forward to the diagnostic video

Cheers

Wayne
Click to expand...

Just googled the diagram as suggested and your one seems to have an extra resistor (the 300 one) - to those I could find - does that make a difference?

I am also assuming 300 refers to 300 ohms ?

thanks

Wayne
 
Yes, could be volts.

The (under the flywheel) coil usually generates between 120-300 volts (AC). The switchbox, CDI (or whatever is storing the power) converts it to DC and then when it gets the trigger (from whatever source - trigger, engine computer etc) releases it to the coils.

On most Merc and Japanese ignitions, the (sparkplug) coils will up the power (DC) going to the sparkplugs to somewhat above 70,000 volts.

Generally when I am doing simple resistance tests on the ignition coil or trigger (if present) I am simply looking for "continuity" or "excessive" resistance.

If there is a break in the winding(s) you will get NO continuity and they won't produce power.

If there is excessive resistance there may be a break or significant degradation and you might get "some power" but not enough.

If you get "less resistance" than spec I generally don't worry because that indicates everything is "intact".

If you have any kind of small engine shop nearby (for motorcycles, lawn tractors etc) they can test your ignition in fairly short order. They all pretty much work the same way and they will have a DVA tester and can tell you "how much" is coming from under the flywheel.
 
Hi all
So I made a DVA thingy and ran some tests just off the cranking battery. The results are:
Red wire from Stator 192V
Blue wire from stator - 162V
Wire from CDI to coil pack - 179V

so that leaves just the coil to test

Does this fit with the symptoms - at low revs up to around 1500 or so it seems to miss. Then as revs increased it smooths out a bit but does use a lot of fuel?

thanks

Wayne
 
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