Trojan Boat Forum

I pulled the alternator off my 454 crusader last evening and was surprised to see only one wier to the alternator. Is this right? or normal. Also, can it be rebuilt? Or would I be better off with a new one. I am removing it because I suspect the bearings in it are going bad, as it (or the) belt would chirp intermittently, and cleared up temporarily when wd40 was applied to the shaft next to the body od the unit. Also, a grinding kind of noise was evident thru a screwdriver when it was running.

One wire alternators are common. Thats what I have on mine as well. If you are having it rebuilt, it might be a good time to tailor it to suit your needs. These alternators are internally regulated which means that the output voltage will remain constant. This is great if your running the power direct to the batteries but if you use an isolator between the house bank and cranking bank, the alternator cant make up for the voltage drop across the isolator. To solve this, the voltage output can be boosted at the alternator when they rebuild it.

Does the alternator produce enough amperage to effectively charge your battery banks? A good rule of thumb is alternator output = 30%-40% battery amp hours. The stock alternators on these engines are often low amperage. (About 30 amps) Now would be a good tome to have this increased as well.

Another trick to accommedate low engine RPM charging is to reduce the pulley size on the front of the alternator. This increases alternator RPM and output at low engine speeds. You do have to be carefull here though since doing this increases the load and reduces the friction area on the belt. Using over an 80 amp output may require a double belt configuration to make this work without ruining belts. A serpentine belt set up would work great here.

some alternators are single wire units. they are "self exciting" such as delco types. what brand of alternator is it? could have that unit rebuilt instead of buying a new one.

Whether you rebuild or buy new, be sure that it is a Marine Alternator or rebuilt to Marine standards, which is built internally protected to prevent sparks. I'm sure you know this, but good to mention for any newbies reading the thread ...

A good marine alternator will feature an external regulator, “hot” rating*, heavy-duty bearings brushes and slip rings, extra large diodes, voltage transient suppresser (Zap-Stop diode), an isolated (insulated) ground (2-wire vs 1-wire), silicon bronze output terminals, and ignition protection or spark arrester (screen on the back to prevent explosions and fire), and have corrosion resistant parts.

It is actually illegal to run an inboard or inboard/ outboard engine with with a non-marine starter or alternator, as enforced by the USCG. I have heard that marine alternators have "USCG" stamped on them, but not sure - and not sure any of mine have this either ... although they are marine parts.

Most likely you have delco easy to rebuild should be around 50-63 amps , the regulator is internal and can not be adjusted


these are inexpensive and do a good job much better in my opinon the the type Rosjo is takling about

I don't know the answer to most of your questions, but it is a marine alternator and I assume a Delco. and has always charged the batteries well. The alternator shop seemed to think it was rebuildable, and said $80 should do it, or a new one for $140. Is that good?

which one has the better warrenty? most of the new ones usually have a good warrenty.

foofer b wrote:I don't know the answer to most of your questions, but it is a marine alternator and I assume a Delco. and has always charged the batteries well. The alternator shop seemed to think it was rebuildable, and said $80 should do it, or a new one for $140. Is that good?

Have it rebuilt.

Both are a fair price , you could just replace the bearings ( cheap ) , but new would be the best way to go IMO


rereading you post have you replaaced the belt ?

The belt was tight and in good condition. I do not believe my engine has many hours since being overhauled in '06.

I suspect the deck hatch leaks onto the engine in that area. Anyone have a simple cure or a way to divert it to the bilge? Currently it just drains out the holes in the gutter around hatch opening.

I used a couple of bilge pump hoses and glued them into the drain holes with some 5200. The hoses run directly into the the bilge. It may be crude but it works.

Paul what are you talking about ?

Got te rebuilt one back and it works well. The shop increased the amperage and made it charge better at low rpm's. Works well. Going diving Saturday. Will post some pics this weekend.

Got te rebuilt one back and it works well. The shop increased the amperage and made it charge better at low rpm's. Works well. Going diving Saturday. Will post some pics this weekend.