140 V4 Weak spark problem.

[Rory140 V4]

Hello guys and girls, I am currently having trouble with my Johnson 1895 140 looper with weak spark from all coils , still has good compression and not sure where to start searching/testing. I would like to know what are the possible causes for weak spark and possible cures for it. I would also like to know the required resistance for the stator both charging side and Ignition side and if there is a way to test coils? (i know i need to get a manual)

I have tried searching but the pages never load...
(got to love the internet)

Thank you
Rory.

 

[Fl_Richard]

Re: 140 V4 Weak spark problem.

Whats the history on this motor. Didi it work perfectly than die or did it slowly deterioriate?

Even with a motor that old (1895) it's rare to have all four coils go bad at once. You need to look at what's driving the coils and check all the grounds.

Is this motor optical ignition?

 

[SparkieBoat]

Re: 140 V4 Weak spark problem.

1985 I assume. not an optical. here is a great guide to troubleshooting your motors electronics.
http://www.cdielectronics.com/downloads/troubleshooting guide/

Your is the OMC 4 cylinder 1978-1998 65-140 HP ..............I think
you really need a spark gap tester and a DVA adapter to determine your problem.
Google DVA adapter, they are about $40 if you already have a multi meter. Check your stator wires, should have 150V+ while cranking, you must use a DVA adapter to test this, or it will burn up your mutli meter.
You also can try disconnecting your rectifier to see if your fire returns, (yellow wires) make sure the wire ends are insulated and do not ground out while testing (this is bad). If disconnecting rectifier solves problem replace rectifier, do not run with rectifier disconnected for and extended period of time, as this controls your charging.
Good luck, Sparkie

 

[daselbee]

Re: 140 V4 Weak spark problem.

I do believe he means 1995.
How about it OP? Some accurate starting data please....

 

[daselbee]

Re: 140 V4 Weak spark problem.

I do believe he means 1995.
How about it OP? Some accurate starting data please....

OOOPPPSSS...no 1995 140s out there...must be a 1985...sorry...

 

[ezeke]

Re: 140 V4 Weak spark problem.

A few possibilities include: bad grounding of the ignition coils; using the wrong (not solid core) plug wires; inadequat starter RPM; and/or incorrect spark plugs.

It's very unusual for all of the ignition coils to fail at the same time.

Use the troubleshooting steps found here:

http://cdielectronics.com/InstallSheet/113-3072.pdf

 

[Rory140 V4]

Re: 140 V4 Weak spark problem.

Well long story short, Was running 9 months ago until put in storage (backyard), when i decided i will start it up just to give it a run. I did all the pre start checks before trying to start it, Anyway after all that it wouldn't start or even try to fire and discovered the no spark and traced it back to the stator, no continuity between the charging coils (cheap second hand one). After being replaced by another second hand one i have a weak intermittent spark problem which now i am currently trying to trace.

Thanks for those links now i can check if the stator is OK, lucky it came with 30 day guarantee if faulty.I have check and cleaned all grounds, and now agree that 4 coils aren't my problem now.The DVA should be done on the weekend weather permitting (got to love off shore cyclone weather) to test the rest of the system.

 

[Rory140 V4]

Re: 140 V4 Weak spark problem.

Well tested the stator on the Brown, Brown/yellow wires and got 362 ohms when the minimum is "Brown Brown/Yellow 450-650 ohms 150V Minimum" Would this be the cause of weak intermittent spark?

 

[ezeke]

Re: 140 V4 Weak spark problem.

Well tested the stator on the Brown, Brown/yellow wires and got 362 ohms when the minimum is "Brown Brown/Yellow 450-650 ohms 150V Minimum" Would this be the cause of weak intermittent spark?

Check each (brown & brown and yellow) wire with an ohmmeter for a grounded condition - engine off. Positive meter lead to wire, negative meter lead to good engine ground. Any movement indicates a grounded condition.

 

[Rory140 V4]

Re: 140 V4 Weak spark problem.

Test and the stator is not grounded, what else can be checked without DVA?

 

[SparkieBoat]

Re: 140 V4 Weak spark problem.

the OHM test did not meet specs....But I would do a DVA test to make sure,,,but it looks like you may have found your problem..I recommend a NEW stator..CDI stators are less costly than OMC and seem to work well. Their support staff is awesome and will try very hard to help you.

 

[Rory140 V4]

Re: 140 V4 Weak spark problem.

well after building a DVA i finally tested it, At cranking speed of a fully charged battery i was getting 97 V, So i am guessing that it is the problem.

 

[SparkieBoat]

Re: 140 V4 Weak spark problem.

that looks like your problem

 

[Rory140 V4]

Re: 140 V4 Weak spark problem.

Ok guys, the bloke i bought the stator off sent me a replacement one, and now has a great blue spark. Got got a question regarding this new stator is this one has 2 orange wires which neither of my other stators have any ideas on what they are or used for?

Edit; Just checked the voltage coming out of it at idle and it is pushing 260 V outs, So...? What to do with it, Just build something to use the energy or maybe a rectifier and turn it in to usable power? any ideas will be great.

Thanks

 

[ezeke]

Re: 140 V4 Weak spark problem.

Sounds like you may have a V6 stator - can you post a picture?

The V4 stator should have one power coil and one charge coil;

The V6 stator will have one power coil and two charge coils.