Altanator experts

[10sec_rx7]

Guys,

have a few problems with the altanator on our ski boat, it dosent seem to be charging at all below 2000rpm which is a big problem cause it spends a fair bit of time below this espically with beginners, at 3300rpm it is only charging to 12.5v

what could be casuing this?? caould be pully be too small and not spinning it enough??

Dale

[GTSBoy]

It may be the pulley, but it would need to be damn small. What does the boat rev to at max? If it a normal sort of range and does not spend large amounts of time at really high revs then you should set up the pulley sizes similarly to the car the engine comes out of (typically anyway).

You should be able to get almost full volts out of it at less than 2000 rpm tho'.

I would tend to think that the alternator might have a suspect diode in the rectifier, or possibly a faulty regulator.

cheers

[10sec_rx7]

i ski at about 3200rpm and i ski the fastest out of everyone that comes with us, it may go to 3800 every now and again for 30sec or so to get past another boat,

i dont know what pully it has on it, i think the motor is out of a HZ holden, it is a 327 chev

at idle it is not charging at all, if you sit at idle for a while the volts drop to 11 and the thing misses its brains out!!

i might pull the thing off and get it checked and maybe re wire everything to the battery, it hasent been touched in the 6 years we have owned the boat. so of the wiring is getting pretty average so ill do that at the same time,

Dale

[GTSBoy]

Corrosion on the various connectors can be a big issue with marine engines too, so perhaps go out there with some abrasives and some CRC to clean it up first.

cheers

[10sec_rx7]

i have had a look at the connectors and they are pretty good, it never gets run in salt water and always gets washed with fresh water, ill pull the alternator off and get it checked out

thanks for the help