2003 250 CXL SW electrical problem

[motway]

ok so the other day i was out on my boat and it started to loose power. for the last month or so i have noticed really bad electrolysis on that engine. while i was out the other day i put the boat up on plane everyting seemed normal, but when i started to accelerate past 4000rpm my low voltage alarm came on, thought at first it might have been the trim switch sticking because it comes on when i when i trim the boat sometimes. so after this low voltage alarm comes on i am watching the guage i switch to the volt meter and jumping between 10.5 and 11 volts. then the engine starts to loose power. so i pull it back to idle and im just idleing along trying to figure out what happened. so the alarm goes off and i idle along for a hundred yards or so and since i only had about a mile or 2 to go to get back to the ramp i say screw it and put it back up on plane to see that happens. alarm breifly beeps when i get on plane and i have the engine running about 3600rpm alarm every now and then beeps at me saying im getting less than 11v. so i turn the corner and have about 300 yds left to go to the baot ramp and try to push it up to see what will happen, so the alarm goes off constantly after 4000 rpm and once i hit about 5000 rpm engine nearly shuts off. i pull it back to idle and idle the last 100 yds or so back in with no low volt alarm going off.

the battery is brand new deep cycle.

theres some pretty bad electrolysis on that engine and teh volds have been reading around 11 volts every time i use it but never had it loose power before.
is there a short that is robbing my alternator of its power or is the alternator going bad.

any help would be great.

had this number on the bracket also OT760570

 

[hamit59]

Re: 2003 250 CXL SW electrical problem

Diagnosis of Alternator System on Engine
1. If problem is an undercharged battery, verify condition has not been caused by excessive accessory current draw or by accessories which have accidentally been left on.
2. Check physical condition and state of charge of battery. Battery must be at least 75% (1.230 specific gravity) of fully charged to obtain valid results in the following tests. If not, charge battery before testing system.
3. Inspect entire alternator system wiring for defects. Check all connections for tightness
and cleanliness, particularly battery cable clamps and battery terminals.
IMPORTANT: RED output lead from alternator must be tight. A darkened RED
sleeve indicates lead was loose and becoming hot.
4. Check alternator drive belt for cracks and fraying. Replace if necessary. Check belt tension. Adjust if necessary,

Alternator System Circuitry Test
Using a 0-20 volt DC voltmeter, perform the following tests:
Output Circuit
1. Connect POSITIVE (+) voltmeter lead to alternator terminal B (output terminal). Connect NEGATIVE (?) lead to case ground on alternator.
2. Shake alternator wiring harness. Meter should indicate battery voltage and should not vary. If proper reading is not obtained, check for loose or dirty connections or damaged wiring
Sensing Circuit
1. Unplug RED and PURPLE lead connector from alternator.
2. Connect POSITIVE (+) voltmeter lead to RED lead and NEGATIVE (?) voltmeter lead to ground.
3. Voltmeter should indicate battery voltage. If correct voltage is not present, check sensing circuit (RED lead) for loose or dirty connections or damaged wiring.

Using a 0-20 volt DC voltmeter, connect POSITIVE (+) lead of voltmeter to TERMINAL B of alternator and NEGATIVE (?) lead of voltmeter to engine ground.
2. Start engine and allow to warm up. Increase engine RPM from idle to 2000. Normal voltage output should be 13.5 ? 15.1 volts. If voltage reading is greater than normal,replace voltage regulator.


At this point if you find and under volt reading from the alternator at 2000 rpm. I would pull it off and take it to and auto electric shop for service.

I hope this helps

 

[motway]

Re: 2003 250 CXL SW electrical problem

great thanks for that info ill let yall know how it turns out.

 

[motway]

Re: 2003 250 CXL SW electrical problem

ok so i went and tried to do the test as listed above, wouldent ya know it my volt meter crapped out. so i did what troubleshooting i could without it. pretty much i took the alternator off the engine and started it, i get the same volt reading with the alternator off the engine as i do when its on. does that mean the alternator is probably bad?

 

[hamit59]

Re: 2003 250 CXL SW electrical problem

Sound like you need a rebuild on your alt. That would be the cheapest way to go. A new one will cost you over 350.00+ . I had one rebuilt a month ago for half of that. You may get by with only a regulator.
I'm glad I was able to help out

 

[yamamarinetech40]

Re: 2003 250 CXL SW electrical problem

Wait, check the alternator first. Could still be corrosion. Get a meter, take it somewhere, whatever, check it.