1990 25 hp mercury does not charge

Hello, This is the same engine that you guys helped me with that was only running on 1 cylinder. Now that it is running great, I found that it is not charging. #1, does it have a charging system and#2, if it does, what do I check? It is a 1990. Serial # OC243437. Thank you. The voltage stays the same when the engine is running versus not running.

Some electric start kits installed after motor left the factory do not have charging capability.----Post pictures of port side of the block.

Look for two yellow wires coming from under the flywheel.

Many from factory simply went to an isolation (block) - a small strip on the block with a couple of screws (one for each yellow wire). If that's the case simply adding a rectifier and the additional wiring necessary to provide a charge function.

If you don't have the two yellow wires then you would also need the charge stator. These produce (with a rectifier) a "rectified" but not "regulated" charge for a battery. At full throttle they produce about 48 watts (4 amps - barely 1 amp at about half throttle) and the voltage varies between about 13.5 and 16 volts - which also means a "marine" battery is required (or tractor battery etc) - one that can handle the "unregulated power.

So sufficient to keep a fully charged battery "topped up", but I would not consider it a "charger".

Having said that, given the cost and time involved IF the charge stator isn't (at least) there already, I would not add one. An hour or two at the dock with a portable charger will yield far better results.