I need diagram on engine and gearbox assembly 115 v4 yamaha outboard

That can be a lot of things...
First off all, disconnect the wire plug to the remote control.
Crank the engine manually ( battery positive on the startermotor post ).
If now you have sparks, then the fault is in your remote control.
If still no sparks, you'll have trouble in the CDI, pulser coils or generator coils.

http://www.yamaha-motor.com/assets/service/manuals/1/LIT-18626-07-95_6E5-101496-Current_1792.pdf

Hey Alex, No, I would get a new bulb..check for leaks in the fuel system.

You can buy the repair manual here:
http://www.fish307.com/clymer-115-250-hp-two-stroke-outboard-jet-drives-1999-2002-b789/

We do not have the info you are asking for. Sorry.

2003 Yamaha 115 4 Strokes Operation and Idle Demo ...

? 2:29
www.youtube.com/watch?v=sMmionreldM
Dec 29, 2012 - Uploaded by Peter Richards Engines for 1989 Larson boat with dual 115 Yamaha 4 StrokeEngines. ... Outboard Yamaha 150 HP DIRTY idle JETS, Motor will not idle .

more info needed but it sounds like fuel,maybe water like condensation

lock lever not down ? does it move up and down at all , the tilt tube could be siezed ,both trim solinoides working ? try standing on the engine gearbox as you trim down or manually release ! if then goes down try injecting the grease nipples with petrol via a grease gun that uses tubes like tooth paste and this will soak the corrosion ! then grease and see if free and if not enough then lift the engine off and remove the tilt tube and clean the sleeves and grease and refit !

Check tilt locks are off,tilt shaft could be frozen

First thing to check: Disconnect the tiny hose between the check outlet and the engine. Disconnect it at the engine side.
With an airgun, blow in the check hole from outside to engine side.
With an airgun, blow out the engine connection.
Start the engine, check waterflow out of the engine connector. If water, reconnect the hose and check the water at the checkpoint.
If still no water at the engine connection: replace the impeller!

not enough information on the motor. what year and model? but all yamaha outboards are shut down by the C.D.I. being grounded by the key switch or the emergency kill switch. the cheapest thing to test or replace is the key switch and the emergency kill. with more info on engine I can help you further.