'02 3.3 Merc won't run above idle

[timjet]

I've removed the carb and disassembled. Blew out all the orifices with compressed air. All looks good but the
motor will not run above idle. Starts on the first pull but when I try to increase throttle the engine bogs down
and dies.
Thanks in advance for any help.
Tim

 

[Ballymac]

Re: '02 3.3 Merc won't run above idle

Best take another shot at it, you may have missed something. Why did you take it apart in the first place?

 

[timjet]

Re: '02 3.3 Merc won't run above idle

I took the carb apart because of the bogging down above idle. I downloaded a Fuel System and Carburetion Guide for the motor from this site. It described how to disassemble and clean which I did. I couldn't find anything amiss except that I could not remove the main nozzle from the carb. The main jet unscrewed from the main nozzle, but the parts diagram indicates the main nozzle should come out. It didn't.
I maybe on the wrong track here with the carb, I'm just assuming the carb is the problem. The motor starts easily on the first pull, but after it starts I have to continually adjust the choke lever to keep it running. Even doing this it won't run much above idle before it bogs down, like it's running too rich or lean. If I put it into forward gear, the motor again bogs down, but sometimes I can keep it running by adjusting the choke, but not for long before it stops. Again it sounds like it's running out of fuel or too rich or lean, but have no idea if that's the problem.
Attached is a picture of the main jet and main nozzle. The first picture is with the main jet attached to the nozzle. The second picture is with the main jet removed. You can see the main nozzle in the carb housing. I cannot remove it. Again I don't know if I'm on the right track here or not.
Thanks again for your help.
Tim

 

[Ballymac]

Re: '02 3.3 Merc won't run above idle

I don't have a manual for that motor. My first thought is to make sure the carb is getting enough fuel. Clean tank, lines, primer & connections? In addition, make sure your lift pump is working. Is there good flow to the carb? Work your way to the carb. If you are choking the engine to keep it running you are sending a rich atomized fuel mix. More fuel less air. Do you have the idle air screws set correctly? If it's a 2 stk, visually check the reeds when the carbs are off.

 

[timjet]

Re: '02 3.3 Merc won't run above idle

Thanks Ballymac. I did check the fuel line. Fuel gravity feeds from the tank to the carb, no lift pump. I blew air into the fuel line just to make sure it is clean. I used fresh fuel and a steady stream of fuel is flowing to the carb. The fuel tank is attached to the top portion of the motor.

Not sure what a 2 stk is. I don't believe there are any reeds. There is a idle set screw that moves the throttle valve up or down to adjust the idle speed. It looks and works fine.

If you agree with me that this is a fuel problem I think the next step is to install a carb rebuild kit. I installed a rebuild kit about 5 engine run hours ago and everything looks fine, but I can't think of anything else to do. The only thing that I can think of is perhaps the bowl gasket is bad or the carb seal which is an O ring that seals the carb to the motor is bad though they both look good.

What do you think?