2000 Yamaha OX66 SX150 150hp running rich

My motor is very slow to start after the initial run. First crank at the ramp and it fires and runs usually on the first turn of the key.. but as the day goes on.. it gets harder and harder to start. Spins and sputters.. spins and sputters. I can smell gas, so I'm pretty sure that it is getting too much fuel. Once I get it running and increase the throttle to plane out.. it runs fine. Its like once it burns off all of the excess fuel its all good. I know that a lot of auto engines have an extra injector that is activated when the engine is cold to make the mixture richer.. but I don't know if outboards do that.
Any ideas..

thanks
Bill Durham

Could be several things. If you haven't done any maintenance, it's probably time to change the low pressure pumps. Clean/replace the VST filter, replace the engine fuel filter, etc. If you've never had the injectors cleaned and calibrated, that's a good idea too. When I got mine, I completely went through the fuel system for piece of mind.

The issue is most like what Joe mentioned. Low Pressure Fuel Pumps.
The gas your smelling are from the diaphragms that leaking. They are
under or around $40 Boats.net has some of the best prices and they are
not hard to replace. They should be replaced every so often as a maintenance
item and if they are originals on a 2000 its time for a rebuild or new...
you can rebuild them but for a few bucks more you can get new


Travis

Thanks for the input guys. I notice on the Boats.net site that they list 2 of those pumps. Does that mean there are 2 in the fuel system? I have replaced the 10 micron fuel filter on the a few times, I fairly regularly clean the spark plugs and did have it tuned up a few years ago but haven't done much maintenance other than that. I had a new impeller installed by Fun and Sun 2 years ago.. they didn't reconnect the speedometer tube when they put it back together..

BD

What is the VST Filter?

thanks
BD

Yes your motor will have 2. Bigger motors even have 3. The vst is the silver tank on the port side of the motor. Unless you are somewhat mechanically inclined, I'd advise getting someone fimiliar with the process to change it.

fairly regularly clean the spark plugs. This does not work on 2 cycle`s. Change the spark-plugs to the BR8HS-10 instead of the BR7`s it will perform much better. Replace the diaphragms or complete pumps. The VST screen will not cause the motor to run rich. Make sure the metering rod for the oil injection is still connected. The plastic ends will break and cause the oil to go full rich.

Michael.. I took a look yesterday at the location of the pumps and it looks like several thinga have to be removed in order to get to the top pump. I noticed that all of the tubing that are connecting to the pumps are held in place by black cable ties.. is that normal? As to my mechanic ability.. I have done a few things on autos in my life.. changed a few clutches, did a head gasket job.. but all a long time ago and not working on an aluminum block. I'm inclined to have somebody do it.

Gary.. thanks for the info on the plugs.. I can do that. I'll check the diagram on the metering rod for the oil injection.. I don't know what that is.
thanks again
BD