Charging Problems

[KingJB]

I have just purchased a boat with twin 94 150 mercs which have been fairly neglected most of their lives. One had a blown powerhead which has just been rebuilt. Both motors run well now but the charging system is f'd on both of them. <br /><br />The first one charges at idle and as the revs go up the charge increases. At running speed the voltmeter slowly increases from around 14.5 to 16 at the same rev and eventually pegs the meter above 16. Thought the meter might be bad so replaced it with new one and get the same result. This motor has a 40 amp charging system with two rectifier/regulators going to a single solenoid. What kind of test can i do to see what is the problem?<br /><br />Engine #2 does not send any charge to the battery. <br /><br />By the way I have isolated the batteries to be one for each motor as I was having a problem figuring out why both batteries were going down at the same time. When they were run through system with both hooked to both batteries the motors would charge batteries fine and after about 20 minutes of running both would stop charging. Have no electronics running when checking charging system. Any suggestions as to whats up?<br /><br />Thanks

 

[Trent]

Re: Charging Problems

First of all alot of setups only had a rectifier and not a combination regulator/rectifier. Yours could just have the rectifier and if so is operating normal. On these setups when battery voltage starts getting high you need to turn somthing on to help reduce voltage. You dont want them to get above sixteen volts because you can blow the CDI packs when voltages get about seventeen volts.<br /><br />Your engine #2 sounds like the rectifier is blown? Since you have two engines, swap them and see if engine #2 starts charging. If not then testing will be required to see if you have AC voltage to the rectifier. Hope this helped some?

 

[KingJB]

Re: Charging Problems

Appreciate the info Trent and it helps a little, but this year and model motor comes equipped with two rectifiers that are also regulators which each take 20 amps from the stator and should never let out more than 15V. I guess what i really want to know now is can i check the system by an ohm test on all the components of the charging system and find out which part is bad or do I need to test them in individually with an anmeter? The ohm test seems like the easiest to do in my driveway without running at high rpms and pissing off all the neighbors, if it will give an accurate assesment of which part is really causing the problem. Appreciate it. Any suggestions?

 

[petryshyn]

Re: Charging Problems

If you e-mail me a schematic of the motor, I'll help....<br />Do you have a schematic?