Rectifier/regulator testing

[metriccrescentwrench]

1990 Johnson 200.

The only test of the combination rectifier/regulator in the factory service manual is a load test with the engine running at 4500 rpm. I can't do that in my driveway. Is it not valid to use the diode test position on a digital meter (as with the earlier engines that used a seperate rectifier) and measure forward and reverse voltage between yellow wires and ground, and between yellow wires and red?

 

[boobie]

Re: Rectifier/regulator testing

Check your PM'S

 

[Faztbullet]

Re: Rectifier/regulator testing

Bench test from CDI
1. Diode plate check:
Test the forward diodes between the two yellow wires and the red wire just like you would on a regular rectifier. You should get a reading one way but not the other. Check the resistance from each of the yellow wires to case ground, you should have a high reading, typically in the M range. The red wire should not read to ground or show
a very high reading, 25M ohms or more.
2. Tachometer Circuit:
Check the ohms resistance between the gray wire and engine ground. You should read approximately 10K (10,000) ohms. Gray to red, and gray to the yellow wires should be a high reading, usually in the M range.

 

[boobie]

Re: Rectifier/regulator testing

If you do this test and it passes does that mean you don't have to follow what the OEM manual tells you on how to check out the charging system output ?

 

[Faztbullet]

Re: Rectifier/regulator testing

If it passes this test the rectifier & tach circuit is good but it does not fully test the regulator side. If it passes test and you have a over charging problem and battery/connections are good usually the rect/reg is defective. Under charging good be rect/reg, stator,connections, etc.....

 

[metriccrescentwrench]

Re: Rectifier/regulator testing

Thanks everyone. I was asking about this not because I think this engine has a charging issue, but because I'm working on tracking down a miss. I'd read through CDI's information about checking powerpacks and noticed they mentioned disconnecting the yellow rectifier wires as a test. While I was at it I took readings with my Fluke and they seemed strange compared to what I was expecting for a normal rectifier. (I totally missed the section in CDI's guide about troubleshooting rectifier/regulators - I'll run through those check this afternoon.)

As of right now I'm suspicious of the power pack, but before I spend money on a new one I want to be sure that's really the problem.

 

[Faztbullet]

Re: Rectifier/regulator testing

Low end midrange or top end miss?

 

[metriccrescentwrench]

Re: Rectifier/regulator testing

It misses at idle, in the water it won't stay running (same problem I've been chasing).

Yesterday I stood out in the cold while the engine idled and moved a timing light from cylinder to cylinder, finally I noticed intermittant misses on several cylinders. The worst was #6, but also noticed it on 3, 4, and 5.

I built a DVA adapter today so I could get the rest of the readings called for in the shop manual - unfortunately I think it's the timer base (but I'm a little conflicted about that). The charge coil was good, 0 volts to ground, and cranking voltages of 198 and 193 (spec is 130 minimum). Sensor coil cranking voltages ranged from 0.74 to 1.19 (spec is 1.2 minimum), so I THINK I'm buying a new timer base. However, I'm a little confused because I looked at the troubleshooting guide from CDI Electronics and they say a minimum of 0.6 volts for the sensor coil cranking tests.

ALSO, it fails the Total Output cranking test from the shop manual (yellow/red wire inside powerpack is disconnected and fast start is disabled) - only get spark on #1 during this test. When the yellow/red wire is hooked up all 6 cylinders show spark. DVA readings of primary wires for # 2 - 6 are all around 5 Volts (using a load resistor ) and 150 Volts for # 1 (with yellow/red disconnected). When yellow/red is connected DVA readings range from 150 to 180 for all cylinders.

 

[Faztbullet]

Re: Rectifier/regulator testing

Pretty much sounds like the timer base is shot. There are several checks like the QS feature of timerbase, internal coil test, advance coil test...