2003 Mercury 25hp 2-stroke Won't Idle Unless Choked and Bogs Under Throttle

[tmkilburn]

Need some help. I can get the boat to idle for a while if I pull the primer/choke all the way out. It will idle just fine and I can open the butterfly and it revs up great. After I push the primer/choke in it will idle for a few seconds and then die. When I've got the boat in the water and I twist the throttle it bogs down and dies. I also have to squeeze the primer bulb after it idles for a bit to refill the carb bow. I lost the o-ring to the fuel filter so gas is coming out of it while priming, not sure if this is causing the fuel pump not to fill up the carb bowl.

Steps taken:
1. Cleaned and rebuilt carb with new gaskets (twice)
2. Changed gas tanks and got new fuel.
3. New spark plugs

 

[Barnacle_Bill]

That O ring has to be there. You are just sucking air and not fuel.

 

[tmkilburn]

That O ring has to be there. You are just sucking air and not fuel.

Thanks for the reply. Before I lost the o-ring it was still bogging down under throttle. After cleaning the carb the first time it was doing the same thing. I emptied the fuel filter to make sure the fuel line primer was pumping gas into it and somehow lost the seal. I have one ordered and am going to replace it in hopes that the thing is fixed. It will rev right up to WOT while on fast idel but while on regular idle it dies when throttle is twisted.

 

[tmkilburn]

That O ring has to be there. You are just sucking air and not fuel.

Thanks for the reply. Before I lost the o-ring it was still bogging down under throttle. After cleaning the carb the first time it was doing the same thing. I emptied the fuel filter to make sure the fuel line primer was pumping gas into it and somehow lost the seal. I have one ordered and am going to replace it in hopes that the thing is fixed. It will rev right up to WOT while on fast idel but while on regular idle it dies when throttle is twisted.

 

[tmkilburn]

That O ring has to be there. You are just sucking air and not fuel.

OK, o-ring replaced and it appears to be idling good and bulb gets hard. No more leaking gas. When I open the throttle the motor bogs down and dies. If I open it really slow from an idle it will rev up but you can hear it want to bog down. What could be causing this? I've been through the carb twice.