Thread: Bad voltage drop
03-05-2012, 11:03 AM #1
Bad voltage drop
I am having an issue with a big battery drain on my 15, when the battery is charged i have 13.3 volts across the terminal, when i turn the key on, it drops to 12.8, then when I hit the starter button it drops to 12.4-5. I have tried 2 brand new batteries and 2 starter solenoids, the starter motor will turn the engine over no problem if its the first time I hit the button but after that it really struggles because the voltage is around 12.3. If the motor is running and I kill it, the battery is around 13.5 so the stator is charging but, again if I try and start it it drops really low 12.2 and wont fire. I also noticed that if I leave the key on with the trickle charger connected 1.5ah the battery will actually drop in voltage over the course of the day. Finally the stop button lanyard won't kill the engine when pressed or removed, I have to use the key to kill it. Like I said earlier the batteries are new and when I had the motor apart the starter looked good
Could yall get some numbers for me? Key off voltage, key on voltage, cranking voltage, and running voltage.
03-05-2012, 12:30 PM #2
- Join Date
- Jan 2009
U have an open circuit somewhere. Just need to find it.
03-05-2012, 02:51 PM #3
I am not sure where to start looking, I have not cut into the harness at all, I checked the temp sensors, rectifier, stator winding, crank and cam sensors, coils, fuel pump, oil pressure switch, and switch housing and all came back good.
03-05-2012, 04:28 PM #4
1stly get a AMP meter amp clamp and see how much drain you are getting when you crank the ski
2ndly when ski is is just sitting how much if any drain is coming out of the battery
and also try with key ON and OFF check current drawn ( amp) being sucked from battery
This will give you a good picture of the circuit condition
then report back
03-05-2012, 04:34 PM #5
I'd look for a dirty ground connection to the battery at the block/starter area. I might also check the + connection at the starter.
If the starter was binding it'd pull the voltage down more, it could still be the starter.
Check the black(BK/W) and white wires from the kill switch-short them at the harness connector and it should kill the engine. Might be rotted switch wires or a bad switch. After that I'd trace back towards the on/off key area.
03-05-2012, 07:30 PM #6
- Join Date
- Jul 2011
Also, as Was said use a current clamp but if you buy one make sure it is a hall effect type that measures DC and not only AC.
03-08-2012, 01:54 PM #7
Key off, 0 amps
key on, 8.9 amps while fuel pump primes, 0.22 amps when off
03-08-2012, 06:34 PM #8
Sounds normal to me, 220ma is very little drain. Start up is normally high for DC motors so 9 amps isn't bad for the pump. Usually they run 5-7 amps continously. Since the battery charges up when running to give 13.5v right after shut down I'd be looking at the starting system. Bad grounds or other heavy connections can heat up after initial demand at which time the circuit resistance gets higher and thus restricts current flow. A bad starter can do the same internally.
Even if the fuel pump 10 amp draw was high for spec, it is not enough to deplete the battery in the space of one start attempt.
03-08-2012, 06:53 PM #9
I cleaned the grounds and checked the connections and they looked better, I pulled the started and cleaned every contact surface and put it back in which helped. I think it might have been timing related because it took a few attempts to fire properly which killed the battery. I kicked the timing up to 6 then 8 degrees at idle and it starts much more consistently but still has some issues. I think the issue was firing at the wrong time and dragging the starter motor down which caused a huge current draw because the starter was still trying to move but under great stress, which is why the timing change helped. I will keep y'all updated.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Racecar_Dave in forum Yamaha PWC Performance (2-stroke)Replies: 6Last Post: 09-22-2009, 08:37 PM
By Surf Junkie in forum Yamaha PWC Performance (2-stroke)Replies: 0Last Post: 09-22-2009, 04:05 PM
By josh_m in forum 4-Tec PerformanceReplies: 38Last Post: 03-24-2009, 09:45 AM
By YudLuz2 in forum Open DiscussionReplies: 111Last Post: 11-05-2007, 05:36 PM
By NateGP1300R in forum Yamaha PWC Performance (2-stroke)Replies: 33Last Post: 07-29-2006, 08:08 PM