Mercury 110 (9.8 HP) dies when shifting or idling down.

[WardenJ]

Hello, I don't know the year of the motor, but it starts up normally and runs well at high RPM idle, but when I idle it down to shift it sometimes dies. Every now and then it will idle down and stay running long enough to shift out of neutral, but when I finish the shift, the engine dies. I have tried raising up the idle via one of those two screws that act as limits for the throttle mechanism, but that doesnt help unless it is clearly too high, and I can't move my throttle control into the "shift" area anymore when I have it adjusted like that. It's clear to me that that method is mearly a mickey mouse repair if at all. Anything else I can look for to solve this problem? Gas and oil are brand new, carb is cleaned out and the needle valve isnt sticking at all. I dont know much more about these carbs beyond that. Any help would be appreciated, thanks.

 

[Papa Joe]

Re: Mercury 110 (9.8 HP) dies when shifting or idling down.

Adjust slow idle needle valve 1.25 to 1.5 turns from seated.

 

[WardenJ]

Re: Mercury 110 (9.8 HP) dies when shifting or idling down.

Where would I find this needle valve? Is that the one accessible fromt he outside of the carb, with the spring wound around the screw? Or is it the one up inside the carb that runs up the center of the body? Also, should I turn it clockwise or counter clockwise? Thanks.

 

[sean321]

Re: Mercury 110 (9.8 HP) dies when shifting or idling down.

I have the same problem. When i am trolling for a couple hundred feet my engine just dies. Start it again and the same thing happens.This motor is a 9.8 hp mercury. What could this problem be ? thanks for any help.

 

[hunterope]

Re: Mercury 110 (9.8 HP) dies when shifting or idling down.

To answer both above.
The screw is the only adjustment available on this carb. It's the one on the right hand side of the carb with the spring on it. I would suggest tunring in till it stops(easily) then backing it out 1.5 full turns. Then adjust accordingly. You may have to fiddle with it a little when starting. (start it with the throttle control in the start position. you will have to monkey with it a bit to get it just right. Also, wait till the motor is warm to make your adjustments. As always, make sure you have the lower unit in the water as not to burn up you impeller. Good luck and let us know how you fare..

 

[Motor Boater Bill]

Re: Mercury 110 (9.8 HP) dies when shifting or idling down.

I would add that you should adjust the idle mix with the ingine in gear--be in the middle of the lake or tied to a pier, or securely tied down on your trailer backed into the water.

On the motor that dies when trolling, there could be other issues that affect low speed operation, like a marginal fuel pump or air leaking into the fuel line (try pumping the bulb--if that helps check fuel system) or cooling (marginal impeller may not cool sufficiently at low speed, check temp of water at the telltale). Crankcase leak is also a possibility, could be crank seals or the small hoses on the side of the crankcase. But check the easy stuff first.

If you post your serial number we can determine the year and also give more specific advice.