Unstoppable 89 mercury 150

[ChrisBurn]

Hey yall, this merc 150 has been swimming twice and is still going strong. Seems to be overcharging the battery as it(the battery) was blowing smoke after a 3 hour cruise. I worked on batteries and voltage regs at Sears in my college years and now run an ac business. Volt meter says 17+ volts at 2000rpm, the reg is watercooled. Anything else to look for? Thanks for your help.

 

[Chris1956]

Re: Unstoppable 89 mercury 150

Maybe it is time to replace the voltage regulator. That motor can charge 40A, and cook a battery as you have found out. CDI Electronics likely makes a replacement.

 

[waynelk]

Re: Unstoppable 89 mercury 150

14.5 volts is the max you are looking for to charge your 12 volt battery. Same as a car. That is a 40 amp system with the water cooled regulator. which are difficult to find used and discontinued new. There are replacements but make sure you get the right one. There is also a two 20 amp stator which uses two regulators for those motors. It has 4 yellow wires instead of 2. I may have a used one around if you get desperate. Usually they fail to charge but you need to replace yours.

 

[ChrisBurn]

Re: Unstoppable 89 mercury 150

Thanks for the help. Found new OEM for 565.00. Whoa! But I think this old merc still has some life and is worth it. Its pushing a 78 v20 wellcraft cuddy. Afraid to put a new motor on a cousin of "Titanic". I'll let you know how it goes.

 

[ChrisBurn]

Re: Unstoppable 89 mercury 150

Changed regulator, but used old o-ring which leaked. Installed new o-ring and everything looks good. Voltage is 14.2 and steady. I wonder if corroded wires (tach, temp, other controls) that were not replaced when motor sank could have caused stress on the regulator. It has been under twice, but with little problems other than this. Thanks for your help.

 

[Jlawsen]

Re: Unstoppable 89 mercury 150

If it happens again, you can order a block off plate for the water cooled regulator and replace it with two new style regulators that are less expensive. I've mounted them on the coil plate and up behind the fly wheel. Those are two places where the fit nicely without any cowling mods. You just need to make a small mounting plate and use the existing bolts in those areas. I use stand-offs on the coil plate to give them a little breathing room.