Yamaha 250 hp carbed please help im stuck

[Captaincrisp]

All the local shops are all booked up for the next while. I have a 1992 txrq 250 hp 2 stroke carbed yamaha. It will idle for 30 seconds to 1 min cold happly Then shakes ( maybe misses) somtimes then dies. It will keep it running above 1200-1400. After its warm it will fire right up again then die in 2-4 seconds. So ive changed plugs (old ones were fairly fuel soaked and carboned nothing crazy though). Then found a leaking fuel pump while testing them. same pumps as ox66 low pressure fuel pumps. Cleaned water seperator on boat and on motor. Also now im running it off of a clean portable tank and new primer bulb. I dont know where too look next. Im thinking of changing thermostats although i doupt thats it. Any ideas would be really apprecated. I need you guys!!!

 

[Captaincrisp]

Ahh comon.. anyone...

 

[99yam40]

sounds like carbs need cleaning

 

[louiefl]

It looks like you have six one-barrel carbs, so I would start by draining each bowl and catching the contents at least on a clean white rag. The lower portion of the carb is the bowl and there is a hex head bolt facing outward. Remove it to drain the bowl. If there is water / crud then that might be part of the problem. Unbolt the air silencer and look down the throat, I forget if there are any air bleed orifices on that side, but if so give it a shot of carb cleaner. More than likely your idle jets are plugged which are located on the bottom of the bowls so you need to remove the carb to spray them out. I'd try draining the bowls and reinstalling the screws. Pay attention to which carb, if any, have debris. Report back as to your findings. Next step is to remove one carb and take it apart, to clean. If you are ok with that then there are 5 to go.

 

[Captaincrisp]

Thanks so much for the awsome advice i pulled off one cover before to look at them. Yesterday i pulled off the other plastic carb cover and noticed all three carbs on that side have fuel puddles in the throat of them. Now i wonder if i just need to rebuild those three or if somthing else is making them leak like that. I noticed that the side that works all the carbs are numbered 1-3 so i assume someone at some point rebuilt that side.

 

[louiefl]

Probably have leking needle valves under the floats. Pull one of the carbs and remove the bowl underneath. The float is held in with a pin, simply slide it out (using adril bit or piece of wire) and remove the float. The needle valve will have a rubber tip that is conical - any grooves or wear means it needs to be replaced.

 

[Captaincrisp]

Ok i rebuilt 3 of the carbs last night boat store only had 4 in town. Ran to my dissapontment exactly the same i decided to screw around with the tps sensor i tuned it so it brought my idle up a little bit . Now it idles pretty nice but when i unplug sensor it dies. I was told there should be no change in idle when unpluged. Or theres another problem.. anyone know what the problem is?