Rebuilt 2000 Mercarb 3.0L

[Cory Nummela]

I just rebuilt my 2000 Mercarb and the engine will not stay running. Starts fine, runs for 5 seconds or so, than dies. Pump the throttle a few times, starts right up, and dies. Any thoughts? The kit I purchased included everything I needed. Only problems, the float I bought would not adjust to the correct settings, so I reused the existing one, and the needle seat would not come out. I reused the seat but replaced the needle. When it does start up, it actually sounds and runs really good, just not for long.

 

[alldodge]

Howdy

Sure sounds like you have a mess on your hands. If it will keep running if the throttle is pumped then its all the carb, but if it only runs after it is started back up, then its the electric fuel pump switch. Once the motor starts oil pressure closes the switch, thereby keeping power to the fuel pump

 

[Scott Danforth]

my first thought is the float and needle/seat.

since you had issues with both of those, I would start there.

 

[Cory Nummela]

I should have stated in my original post that my boat was running before. When I would try to accelerate, it would hesitate bad and would stall out unless I put it back to neutral. Idled fine when in neutral. When I would shut it off, it was as if it wanted to keep running, than would die. Everything I read and was told is the carb needed a cleaning and carb kit. Now it will not stay running. To me, it's not getting gas for some reason? Would the fuel pump go out like that? Was it maybe going out before?

 

[alldodge]

Fuel pump would not just stop after a carb rebuild, so the carb needs to be rebuilt correctly or needs replaced

 

[Scott Danforth]

see post #3.

your needle/seat and float have issues.

 

[Cory Nummela]

UPDATE...I took the carb apart again and was able to get the old needle seat out. I soaked the carb in a can of carb cleaner and blew everything out with an air compressor. I replaced the seat with a new one. Also replaced the float and plugs. Engine now starts and runs really good and smooth with fast idle. As soon as I pull throttle back to neutral, or close to neutral, engine dies. Starts back up with fast idle, dies in neutral. It seems like an adjustment somewhere, but where?

 

[Bt Doctur]

idle mixture ? From GENTLY SEATED open them up 3-4 turns and see.

 

[Scott06]

What BT said sand is it possible that the idke speed screw is backed out too much? Turn it in a bit as it will stall if backed out too far. Set mixture and idle speed in gear, in the water to about 650 rpm