140 hp Mercury outboard dies when put in gear

Vanard · #1 May 17th, 2007, 04:59 PM

Please help, I know absolutely nothing about boats, first one, but am wanting to learn...
So the problem is when I put the boat in gear when it's in the water it just dies. But when I'm at my house with the house it's just fine...
Any ideas on what I can do or what this is???

yorkserv · #2 May 17th, 2007, 05:42 PM

I am having the same problem with mine if you want check out the threads i posted on a similar topic i have an 88 200hp blackmax i got a couple of pointers on where to start i am working on it now if i get anywhere i will let you know

click here: http://forums.iboats.com/showthread.php?t=196259

tashasdaddy · #3 May 17th, 2007, 06:34 PM

no one mentioned backpressure, and lack of, if you are setting you idle on muffs, it has to be set approx 100 rpms, high, as there is no backpressure on the exhaust. then it has to the fine tuned with the motor in the water, it has to run faster out of the water to compensate for the backpressure.

Vanard · #4 May 17th, 2007, 06:38 PM

Thx. for the link, I have replaced all of the fuel filters, fuel lines, old gas, sparkplugs, wires, and distributor cap...This thing sat for over a year before I bought it. So I did a bunch of preventative maintanance. It dies the moment I put it in gear. I can open the throttle manualy as long as it is not in gear and it's fine, but the moment it's in gear it just dies out...Any ideas???

Vanard · #5 May 17th, 2007, 06:40 PM

How do I go about resetting the backpressure, or adjusting it to be aroung 1,000 rpm in the water

Chris1956 · #6 May 18th, 2007, 10:01 AM

Vanard, What you have described is the classic example of the idle mixture being set too lean. Since these motors do not have an accelerator pump, the idle mixture needs to be richer, to compensate. You can try to richen the mixture by opening (CCW turn) the idle mixture screw 1/8 turn on the top carb (inline six, right?). Now try to accelerate. Open the mixture screw on the middle carb 1/8 turn and try to accelerate. Repeat with bottom carb, and then redo sequence (top - mid - lower) again. The idle mixture will end up being as rich as can be had, while still having a reasonable idle smoothness.

If you do not have any luck, the carbs likely need cleaning.