Charging problem 3.7

[theonlysneakyone]

Okay, so i just bought a 1989 Carver santego with twin 3.7LX mercruisers. Keep in mind my batteries are not fully charged but will be soon. Right now the batteries have about 12 volts. So i start the engines, obviously the volts drop and then go back up to 12.2 and then slowly climbs ran it for about 5 minutes got to about 12.35 did not really mess with it. Now this is my first I/O engine i know with a normal engine i should get 13 - 13.5 volts, also noticed that it has the magnets on the crankshaft pulley and a water cooled regulator seems kind of janky IMO. just was wondering if this was how that this charging system is suppose to work. If this is not right i would like to know how it is suppose to work. Also the wiring on the voltage regulator looks correct.

 

[Don S]

Re: Charging problem 3.7

Now this is my first I/O engine i know with a normal engine i should get 13 - 13.5 volts, also noticed that it has the magnets on the crankshaft pulley and a water cooled regulator seems kind of janky IMO.

Well, you don't have a normal engine, you have what is commonly known as a 470, and yes that charging system is a lot "janky".
At idle and low rpm you won't get much output from the engines charging system. See if the charge voltage increases as the rpm gets up around 2000.
Most people convert to an alternator instead of fixing the OEM, it's a lot cheaper. Many of the part a no long avalible, and the ones that are available are very expensive.


There are also other built in problems with that engine, you never want to overheat it, and keep an eye on the oil and antifreeze level as the cam seals are known for leaking antifreeze into the engine.

 

[Bt Doctur]

Re: Charging problem 3.7

It only lives if you keep the batteries in good condition. Never try to charge a dead /weak battery off the system.Never use "both" with weak batteries. Replace batteries at the first sign of trouble.

 

[a1nowell]

Re: Charging problem 3.7

Breezeworks has the altenator conversion kit you want. If you own a 470 you are going to make the conversion sooner or later.

Larry, 470 owner since'08.