Flywheel Advice

[Man 'o Kent]

1 hour ago, Slim said:

Leaving aside all the other points I would go along with Boater Sam regarding the size of the alternator pulley.  I've got a smaller one than the one in the photo on my A127 alternator. Got it from a motor factors years ago.

 

Frank

I'll second that!

 

Even with everything electric sorted that alternator still needs to rotate a LOT faster, maybe as much as 6 times faster with an engine rated at 1,600 rpm(?). Given the space available and the need to transmit, allowing for losses, something like 1½  HP that 'aint going to be easy.

 

In order to gain as much room for the largest pullies possible it might be an idea to chage the "V" belt drive for the toothed belt type.   A "V" belt takes about 8mm off the effective diameter of a pulley, a toothed belt sits on the top of the pulley so "wastes" no diameter but allowance has to be made for the thickness of the belt plus clearance. But in a tight space every perishing millimeter you can gain is worth having!

On the downside you would still need a countershaft and probably still not get the full rated rpm/output from the alternator.

On the upside you would need barely any belt tension thus giving the alternator's bearings an easier life.

 

 

 

[ste_b]

7 hours ago, Mike the Boilerman said:

 

Yes I was wondering why no-one has asked this yet too!

 

Dear OP, does the charging warning light

 

1) Illuminate before the engine starts, then go out after revving it up? Or

2) Stay alight all the time? Or 

3) Never illuminate?

 

 

 

7 hours ago, Tony Brooks said:

However its an old boat so the electrics may well have been bodged on bodge so it may not even have a warning lamp. Feeding the D+ direct from the battery might explain flat batteries and a non-charging alternator.  It might use a rising oil pressure switch so a faulty switch woudl prevent charging (I am not saying anything here is true or correct practice).

 

The electrics are a nightmare. Totally bodged and in need of ripping out and starting afresh. There doesn't seem to be a light in the circuit as far as I can see.

 

I'll use the advice given so far to have another prod around the electrics and have a think. Thanks.

[Boater Sam]

If there is no ignition lamp, that is maybe why it never charges.

Before you go to far, wire the alternator directly and see if it works. You only need to wire the B+ terminal to battery+ and put a 2.2 watt lamp (really whatever you have will do )  between B+ and D+. It will light up.

It should then charge when the engine is running and revved.. The lamp should go out when it is charging.

[OptedOut]

What is the model number on the alternator data plate?

[ste_b]

There isn't much in the way of markings on the altenator. It looks like a Lucas A127 or clone.

 

I've added a bulb to the circuit, which has helped. I tried a 1.2W bulb, which stayed illuminated and the battery didn't charge, even after increasing the throttle. With a 2.2W bulb it went off straight after starting the engine and the battery showed a charging voltage of above 14v.

 

Thanks for everyone's advice - it's helped a lot.

[bizzard]

1 hour ago, ste_b said:

There isn't much in the way of markings on the altenator. It looks like a Lucas A127 or clone.

 

I've added a bulb to the circuit, which has helped. I tried a 1.2W bulb, which stayed illuminated and the battery didn't charge, even after increasing the throttle. With a 2.2W bulb it went off straight after starting the engine and the battery showed a charging voltage of above 14v.

 

Thanks for everyone's advice - it's helped a lot.

Goody, goody, gum drops.

[MtB]

6 hours ago, bizzard said:

Goody, goody, gum drops.

 

Basil Brush, IIRC. 

[Boater Sam]

12 hours ago, ste_b said:

There isn't much in the way of markings on the altenator. It looks like a Lucas A127 or clone.

 

I've added a bulb to the circuit, which has helped. I tried a 1.2W bulb, which stayed illuminated and the battery didn't charge, even after increasing the throttle. With a 2.2W bulb it went off straight after starting the engine and the battery showed a charging voltage of above 14v.

 

Thanks for everyone's advice - it's helped a lot.

And thank to you for the thanks and coming back to say that it works,,,, most don't bother.