Trim motor or alternator

[dls]

Again I have a strange problem. I have a 1999 OX66 200. My motor is running good, idle 500 r's in gear, 5800-5900 r's, compression is in spec's, no missing or hissing. Normally as we trim up the RPM's go up. When I trim up you feel the motor start lugging, like you are pulling a skier, the RPM's are still climbing but slower. I quit trimming and it picks up. It doesn't do this every time. My voltage is 13.5 volts and when I put it in gear and take off it will drop to 11.5 to 12.0 volts through out the trim range. Is it possible that some how when I trim up it is drawing voltage from my plugs causing the plugs to have a weak fire ? My voltage drop is the same as it has been since 2001.

[CJ1]

Yes, the trim motor is drawing more than the engine charging system can put out, so it pulls power from the battery. If it can't get power from the battery very well the voltage drops below the 12.6 or so the battery can deliver. Bad wire, connection or battery. I would do a loaded voltage drop test on the main cables to start with. Be glad you don't have a SHO, it would just shut off! Cj

[yam911]

Exactly.

If you need help understanding a loaded voltage drop test, just ask.

[dls]

Thanks for the replies CJ1 and yam911, I have a optima blue top battery and I check all of my batteries every 2 to 3 months with a load tester. So far all check good. If all electrical checks are good should I replace the pump and if I understand correctly my volts should not drop below 12.6 when I am trimming up ? Thanks again for the help !!!

[Bass Junkie]

There's a bunch of guys on this site that have had bad luck with the blue tops, me included. You mileage may vary but that could also be the root of your problem.

[CatFan]

Check both battery cables at both ends for corrosion or looseness.

[CJ1]

Thanks for the replies CJ1 and yam911, I have a optima blue top battery and I check all of my batteries every 2 to 3 months with a load tester. So far all check good. If all electrical checks are good should I replace the pump and if I understand correctly my volts should not drop below 12.6 when I am trimming up ? Thanks again for the help !!!

No, very unlikely the trim unit is drawing that much. It would almost have to be.grounded out. OK, your charging system delivers say 50 amps. Your trim draws 100. So your battery has to supply 50 amps to your engine/trim unit. If the wiring/connections are bad the voltage the engine sees is way low as you are describing. And WILL cause running issues. The 2 main cables should be the first you test with the voltage drop test. Use a DVOM with min/max recall. Turn it to DC volts hook one test lead to the - battery cable at the battery and the other end to the - cable end at the engine. Hook it on the cable ends that eliminates the connections. Run the tilt trim. The meter will record the voltage difference or loss of the cable. That is what you want to see. So this on the positive cable also. If you see a couple of volt drop you found your problem. If your battery is at 12.6 and you trim and loose 2 volts your engine is "seeing" 10.6. Another way to do this is hook meter to the battery and trim it. If it looses a couple of volts then look at the battery or connections. If it stays around the same voltage or drops .5 or so then test at the engine. If it is a big difference check the cables. If all that checks out do a amp draw on the trim tilt unit. But that would be the last test as you need a current probe. I realise this may sound complicated but it is easy and only takes a few minutes. I am still betting on a bad main cable or connection at engine or battery as the others have pointed out. Cj

[CJ1]

I just looked at your numbers again and from memory I don't think mine drops below 12.7 to 12.9 on my digital gauges. Where are you seeing the 11.5? Anyway do the tests and report back. They will cost nothing but a few minutes of your time. Cj

[dls]

Thanks again everyone, I will do these test as soon I can. The voltage drop I saw was on my Yamaha digital gauge. It was funny to me with my motor running but in neutral it only dropped .2 of a volt but in gear at wot it was 2 volts. The day after posting this I went fishing and she ran like a champ and still was dropping 2 volts at wot. Never did it all day long, I hate a "When I feel like it problem" hanks again and I will let you know the results.