Mercury 6 hp 4stroke won't rev down

Pip42

Recruit
Joined
Jan 28, 2013
Messages
1
Recent recurring problem with my 2006 Merc outboard, well-maintained, but won't rev/slow down. I can turn the throttle completely down, but the engine keeps going at high power.
To get back to dock yesterday, I needed to force it into neutral and reverse, because the engine won't slow enough to do it right. It also starts up at a very high speed, not the normal one idle.
This first happened in October, so I took it in but they couldn't replicate the problem in the shop. They checked all the normal suspects connected to the throttle but didn't see anything. There were other issues which they dealt with (related to our crappy gas in California and some corrosion from a plugged intake site) but they couldn't find anything wrong with the throttle and after working on the other issues, it ran well in the tank.

I put it back on my boat - it started up a little high but not outrageously so, but an hour later I couldn't get it to back off enough to get it into neutral to dock it.

I know the repair guy checked the cable and he mentioned some springs that can break, but which seemed okay.
Does anyone have any other suggestions since he couldn't find anything wrong with the throttle last time?
 

halmc

Petty Officer 1st Class
Joined
Feb 27, 2008
Messages
231
Re: Mercury 6 hp 4stroke won't rev down

Recent recurring problem with my 2006 Merc outboard, well-maintained, but won't rev/slow down. I can turn the throttle completely down, but the engine keeps going at high power.
To get back to dock yesterday, I needed to force it into neutral and reverse, because the engine won't slow enough to do it right. It also starts up at a very high speed, not the normal one idle.
This first happened in October, so I took it in but they couldn't replicate the problem in the shop. They checked all the normal suspects connected to the throttle but didn't see anything. There were other issues which they dealt with (related to our crappy gas in California and some corrosion from a plugged intake site) but they couldn't find anything wrong with the throttle and after working on the other issues, it ran well in the tank.

I put it back on my boat - it started up a little high but not outrageously so, but an hour later I couldn't get it to back off enough to get it into neutral to dock it.

I know the repair guy checked the cable and he mentioned some springs that can break, but which seemed okay.
Does anyone have any other suggestions since he couldn't find anything wrong with the throttle last time?

What's the history of the issue? Did this arise slowly, quickly, after it was worked on?

I'd take the cover off the engine, and w/o starting it, put it in gear and observe the workings of the throttle. it's not complicated. You'l be able to see the throttle saft turn in the carburetor as you turn the throtte control on the tiller. You'll also be able to see the little screw that sets the idle speed on the throttle right there at the carb. Make sure that the whatever is supposed to make contract with the screw when the throttle is wound down, is doing so. if it isn't, figure out why.

There is also a possbility of an air leak in the intake path, but it's not very likely.

I'm assuming it is tiller control, yes?
 
Joined
Mar 30, 2008
Messages
14
Re: Mercury 6 hp 4stroke won't rev down

Also check the choke cable, it has a throttle lifter on the first half of the travel, sometimes the cable can get sticky and not go back all the way when you push the choke in.
Brian Evans.
 
M

Maxz695

Guest
Re: Mercury 6 hp 4stroke won't rev down

The manual choke sounds likely but try running it with the cowel off of the engine and see if it sill happens.
 
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