95 Sportjet 120 melted Voltage Regulator

[gambling man]

Took it out last week, and had to crank it a few times to get it started. Negative wire was quite hot. Had it out on the lake and engine quit. No roughness, just quit. Decided to call it a day and started in....quit at least 20 more times...no problem starting, just kept quitting. Not a stall, just quit. Once at port, lifted the engine cover and noticed that the Voltage Regulator had literally melted and burned. Could this just be due to a corroded battery connection? I have ordered a new regulator, but should I check anything else before I install it? I would hate to waste $125. Any help would be greatly appreciated.

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

You need to check for a short to ground and check all your grounds , Check the battery for an internal short, Voltage test and load test (take to Auto Zone type store and they can check it ) Dirty battery terminals are a no-no. These did have a problem with a backfeed to the regulator when they cut off . Your next biggest worry should be did you fry the switchbox ? Run a switchbox bias test as follows after you install the new regulator and before starting engine :

1. Voltmeter set to 20v DC
2. Red voltmeter wire to good engine ground
3. Black voltmeter wire to White/Black wire at switchbox
4. Crank engine, reading should be 2-10 volts

If not post results and we can go from there.

PS is there any way you can post a pic of burnt regulator on the engine ?

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

I will post a picture when I get home tonight.
Also, I will take the battery to autozone tonight and get it tested. The New regulator (CDI) comes in tomorrow, so hopefully I will have it on and tested by tomorrow night. PS, the battery terminals didn't seem that dirty to me, a little white powder.....but I was using the wing nuts, and had just trailered it about 60 miles...maybe it loosened up the attachment.

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

That "hot" negative wire concerns me , Check ALL your grounds to be sure they are rust free !

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

Does anyone have a list or a diagram of the grounds so that I don't miss any?

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

Main battery cable , coils , switchbox ,low oil sensor , rev limiter , Stator adapter and never a bad idea to run one from the mounting plate for the ignition components to the battery . All other grounds are established by mounting bolts for the item .

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

FYI, I want to correct something, it was the POSITIVE cable that was hot, not the negative. Sorry for that. Part will be here tomorrow.

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

Sorry about the quality, these were taken with my phone. I took the bolts off the plate to check behind it, and the coil has some black burnt rubber on top of it, but it doesn't seem to be affected otherwise.

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

Bolt it on and do the tests I asked you to do , if they pass , Drink One for the boat Gods and fire her up !

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

Well, the boat fired right up, and ran. Not real fast.....no spark on one cylinder. Can you guys point me in the right direction for the testing procedures for a 95 120hp?? A mechanic told me probably the coil, but from reading this site, seems more likely to be stator or trigger.....

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

Gonna do some research , reohm the trigger and post results , Also did your switchbox pass the test I described above ? ( post number 2 )

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

To OHM a 120 trigger disconnect all 4 trigger wires , ohm white to purple note reading , next ohm brown to white/black , readings should be between 700 and 1000 ohms

 

[gambling man]

Re: 95 Sportjet 120 melted Voltage Regulator

Sorry haven't posted in a few days, but a mechanic friend of mine pulled it out to his house (on the lake) for easier testing. Anyhow, he ohmed the triggers and the stator, and they were "within specs". (He didn't give me the numbers) He took it out to test it and on a whim, detached the rev limiter. Runs about 43-44mph with two 200lbs men in it...Special thanks to Kend, you definitely should start a business.

 

[kend301]

Re: 95 Sportjet 120 melted Voltage Regulator

Sorry I never mentioned that , I assumed you had read the top thread about the rev limiter wire . BTW did you disconnect it at the switchbox or at the rev limiter ? Makes a difference in what you do next . One will be a rev limiter the other will be testing the harness and Ignition switch.