Merc 125 2 stroke accelerating hiccups

[slayer2]

Guys... I am looking for some pointers .. I am running an 04 merc 125 2 stroke outboard and at say.... 600 rpms in gear and just when it accelerates and takes off on plane... I get a miss or so and every once in awhile when I throw the throttle down.. It is slow to accelerate and then she runs fine at wot. I have a new set of plugs and they are gapped right at .40. That is about the only thing I have done. New gas and not ethanol. Any ideas? Fuel filter has not been changed and I don't know how long since that has been done either as I recently inherited the boat and motor. Thanks in advance if anyone can help.

 

[jerryjerry05]

Re: Merc 125 2 stroke accelerating hiccups

Should be about 750-800 in gear.
Re-set the air screws on the carbs.
Water in the gas?

 

[carholme]

Re: Merc 125 2 stroke accelerating hiccups

Idle is 650-700 per the manual.

See under Specifications, page 1A-3

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/830234r3/cover.pdf

You must have Adobe Acrobat reader installed to use this manual. If you scroll down to the lower part of the opening page, you will see the various engine components in red. Click on the one you want and when the first page opens, click on the "Save As" icon at the top LH corner of the page and you can save it to your computer.

Parts listing:

http://www.crowleymarine.com/mercury-outboard/3745.cfm

Gerry

 

[slayer2]

Re: Merc 125 2 stroke accelerating hiccups

Should be about 750-800 in gear.
Re-set the air screws on the carbs.
Water in the gas?

Not sure on the water in the gas... The tank has always been kept full since I got the boat. I did run some stabilizer in it when I purchase it. Can a guy drain the tank in boats? 04 Crestliner 1750 fish hawk? I should look in the manual and see if they have instructions on air scoop adjustments... Not sure if I have the capability to successfully mess with that.. May just take it in to the dealer and have it worked on when the season slows up.

 

[slayer2]

Re: Merc 125 2 stroke accelerating hiccups

Adjusted the top 2 carbs per the manual to 1 1/2 turns out and will set idle to factory spec when in water and in gear and see how I works

 

[CharlieB]

Re: Merc 125 2 stroke accelerating hiccups

Over time the fuel passages in the carbs begin to accumulate mineral deposits, and restrict fuel flow.

The main passages and jets are large enough the % restriction is minimal and rarely noticed.

The IDLE passages and jet are much smaller, it takes very little restriction and you soon notice poor acceleration.

You 'may' get lucky by adding SeaFoam to your fuel and desolve enough of these deposits that acceleration is restored. Then again, that 'may' dislodge chunks, further blocking flow on one or more cyls and worsen the condition, requiring the carbs to be removed for proper cleaning.

Your call.

Either case, regular fuel treatment with SeaFoam will greatly increase the time between carb cleanings and help keep your motor running sweet.

 

[slayer2]

Re: Merc 125 2 stroke accelerating hiccups

Makes sense... I am thinking my issue could very well be that my idle in gear rpm is too low that when I throw the throttle all the way down... I get a hesitation before the balls kick in.. Just seems to me that if I have proper idle speed rpm adjustment; the acceleration would be better. JMO I guess. I will fill er back up and add a proper amount of sea foam to the girl and set the idle speed rpm in gear and see how things look. Hard to do without a tank but have to remove the cover and go to the lake and reach around the motor and set it. How does this sound?

 

[slayer2]

Re: Merc 125 2 stroke accelerating hiccups

Well guys... I found out today that this engine I have is the 2 + 2 design and they all run like this.