Hi there, newbie so please be kind. I have a 40hp yamaha with no serial plate on it. Im told that by its look it is a 79-81 model, its electric and pull start. ( i know, vague) but when i try to buy parts they always seem to be not quite the right fit. Can anyone tell me the model if i put some pics? It is a twin cylinder, single carb. I also need to find out how to wire the tacho, and have found the two green wires coming from the stator but they dont seem to have any current as i tested them with a volt meter. But i got the tacho working, albeit eratically with a yellow spare wire also from the stator. Sorry if this seems a bit vague, please let me know what informattion i need to give. I wish to charge the battery as well but the rectifier appears to be missing too. (screw hole where i think it was fitted) It runs like a dream but just needs a few more things tweaking and i want the electrical system to work to its full capacity. Many thanks in advance.