2001 mercury tracker 40 hp 2 stroke oil injection

[fosterthedog]

Have a 2001 2 stroke 40 hp oil injection mercury tracker outboard. Have had it in a mercury shop twice. Both times I put it on the water it does the same thing. Will not idle in neutral,unless you use fast idle. Then you have to get it in forward and throttle up to about 3/4 then it will level out and run like a top. If anyone could help please.I have emptied fuel tank, refilled with good 92 octane fuel. The shop say they adjusted carb. and new plugs.

 

[ondarvr]

Did anybody clean the carbs?

 

[DavidMoore]

I would say:

Dirty carbs, or
Idle set incorrectly, or
Low speed circuits on carb set incorrectly, or
Operator error, or
A combination of 2 or more of the above.

You are letting the engine warm-up before lowering the lever? Lowering of the lever is a gradual thing.

Is the boat normally on a trailer? If so will it start and idle normally on muffs and what speed is it idling at when on the muffs.

With engine in water, in neutral, and warmed up, can you get it to idle @ about 750 rpm by using the fast idle lever?

Find the low speed adjustment screws on the carbs, with engine off, whilst counting the amount of turns needed, slowly screw them in until just lightly seated. Then back them off the same amount of turns.
Report if that made a difference or not + the amount of turns you needed to make.

 

[fosterthedog]

I am leaning toward dirty carbs. I am 57 have owned boats outboards for years . Boating season in Ohio is almost over. Next spring I will have in the shop early hope to find the answer. The carbs were adjusted motor ran well for a short time. Then back to not idling in neutral. As I say it runs well in every other way.

 

[DavidMoore]

That puts a new perspective to the issue.
I will go with the dirty carbs too. Ever changed the fuel lines, the older fuel lines are a common cause of carb problems.