merc 175?

[81hydrostream]

I have a 1986 MERC 175 black max. when im running at speed the motor is fine and take off is normal. but the moment that i start driving around the dock it always wants to stall it will not idle very long before dying out. when you apply just a little gas to idle out and keep the tach at about 1000-1200 its fine. other then this problem the motors runs great. any comments?

[rob vaughn]

I'd just raise your idle speed up... Do it in neutral ( keep it at 1000) & I would check to make sure my timing advance arm is in the correct position...

[MTCM]

Check:

Fuel Tank for possible sticking Anti-Siphon (ball check) valve. If it has one, remove it. They are usually located in the nipple where the fuel line attaches to the tank. If this valve is sticky, the vacuum operated fuel pump on the motor does not have enough "nuts" to pull it open at low RPM. Check for other obstructions as well. Make sure the fuel tank vent is not obstructed too.

Fuel line from tank to fuel pump. If you have the "squeeze bulb" type, replace it. These things have check valves that can stick as well.

If you have (and are using) the vacuum operated fuel pump on the engine, it may be weak. Rebuild it.

One way to eliminate or determine the first two items as problems is to get another tank (portable) with fuel line and run your engine on that tank and see if it behaves the same. If it still runs poor at low RPM, I would start looking at the fuel pump.

[81hydrostream]

I do belive that my idle is a little low. i have a secondary electric fuel pump to pump the fuel from the tank to the motor so i dont think that is the problem but one thing that i did notice that i forgot about is when it does idle either unburned oil or gas is coming out of the exhaust ports above the water?