1999 Bayliner Capri 1750 Self-induced wiring issues (battery backwards)

[bobec_97]

I replaced the entire fuse block on my 1999 Bayliner Capri 1750 (3.0 mercury, alpha 1 outdrive, I/O) because the connections were in terrible shape. When I hooked up the battery, everything seemed to be working great. All the lights came up, the instruments worked, and the blower fired right up. I disconnected the battery to do a final mounting of the fuse block. At this point I was pretty happy!

That all was about to change.

When I reconnected the battery, I stupidly connected the battery backwards. I didn't even notice until the alternator (regulator I think) caught fire.

Amazingly, I could not find any damaged wiring. It also looks like the fuse on the starter somehow didn't blow.

I replaced the entire alternator (and inspected the wiring) and reconnected the battery (correctly this time). However, at the main instrument panel connection, and also at the starter terminals (and other places) I am only getting 7.5 volts. The battery is fully charged, and if I disconnect the + terminal, it registers 13.3 VDC.

I'm stumped - is there anyone who has had a similar experience with this boat that might be able to give me a new place to look? I've seen several wiring diagrams that are supposedly for this boat, but they don't seem to match up exactly. For example, I don't seem to have the circuit breaker shown in most of the diagrams.

I'd really hate to have to junk this boat over my stupidity so I would really appreciate any suggestions.

Thanks in advance.

Bob Clabaugh
Warren, OR

 

[NYBo]

Reverse polarity wouldn't blow the starter fuse, so that's understandable.

Did you turn anything on with the battery hooked up backwards?

 

[sam am I]

I am only getting 7.5 volts. The battery is fully charged, and if I disconnect the + terminal, it registers 13.3 VDC

Couple questions

I assume the "+ terminal" you referring too is the alternator's + terminal? can and is also called the "Batt +" / "B+ terminal"?

When you were measuring the 7.5 VDC in those various places that went up to 13.3 VDC when dis-connecting the "+ terminal", where EXACTLY was your meter's ground/black lead connected too?

Is the alternator a 3 wire type?

 

[bobec_97]

Sorry, I should have been more specific. I hooked the battery cables up backwards.

The alternator IS a three wire version.

When I was measuring the voltage the ground was connected directly to a (paint removed) part of the engine block.

Also, yes, I tried to turn over the engine and flicked several switches while the battery was connected backwards. When I removed the + batters lead(s) and measured between the engine block ground and the + battery terminal the meter read 13+.3 VDC.

Specific measurements that were low: positive starter terminal, starter solenoid terminal, direct positive feed to the instrument panel. Ground was an alligator clip direct to the engine block (top) with the paint scraped off.

I had previously replaced the ground cable from the battery to the block with a brand new one. And he large battery cable to the starter was replaced as well. All the remaining connections were vigorously cleaned up using a wire wheel attachment on a Dremel tool.

One other point - the outdrive trim (all the way up to trailer position) still works.


Thanks for your replies.

Bob Clabaugh

 

[sam am I]

No Title

No problem, I probably just needed a clearer picture.


So, see attachment (I think close to your motor, works enough for all intensive purposes anyway) .........and

Specific measurements that were low:

Then in section B of the attachment

Ground was an alligator clip direct to the engine block (top) with the paint scraped off.

Assume is "A"

positive starter terminal

is area "C" but is a bolt with a insulated strap that goes directly into the main starter body....this one I'm not too sure on, Is this the correct location?

http://forums.iboats.com/forum/engin...tion-on-a-3-0l

post #1 picture 3

starter solenoid terminal

is area "C" where the red and orange are bolted together

http://forums.iboats.com/forum/engin...tion-on-a-3-0l

post #1 picture 3

direct positive feed to the instrument panel

is ( or is essentially )area "D"


And assume your ground is good (based on you just replacing with good new wire) and your voltage is dropping in those area's listed above to 7.5 VDC with the battery (area "B) hooked up, if your NOT **drawing a pretty good arc hooking it up as it drops, I'd say 1) Your battery is toast or 2) the battery's positive post clamp/crimp/wiring is flaky.


For 1)......Hook the battery back up to where you have the 7.5 VDC readings ground referenced from area "A", measure then from one battery post to another. should be 12-13 VDC, if that measures good...it's wiring (pretty high resistance in a line somewhere since it's not arcing when you hook up the battery and it's dropping 5.8 VDC)

For 2) Still with battery hooked up and reading the 7.5 VDC in those area's ground referenced from area "A", measure from the Battery post (not the post clamp, but the post itself) to area "C", you should see 13.3 - 7.5 = 5.8 VDC.

That 5.8'ish VDC drop has to be in either that local positive path or perhaps the ground isn't so good anymore? A now loosened ground bolt/flaky connection in area "A"'s negative path from the battery neg. post could have shown up.

**A shorted (not zero ohms obviously) device down stream could drop the voltage (Battery) but as you hooked up the battery, it would draw a fair amount of current, arcing when connected.

GL