Merc 115 acceleration proplem

I recently rebuilt the carbs in my 94 Merc 115...and took it out today for the first time since the rebuild. After working with the low speed idle screws on carbs 1 & 2 I felt like I had the idle settings about right so I tried the mix in gear. Engine kicked into gear a little hard but not more than before the carb rebuild, but then when I tried to jump on the throttle to check a simulated hole shot the engine bogged and shut down. After trying a couple more times the engine would do the same bogg down and the seem to JUMP into higher RPMs. Nothing smooth about the transition. Do I still have work to do to link & sync my carbs correctly or am I seeing a problem from somewhere else?

Thanks
dr

Re: Merc 115 acceleration proplem

Do I still have work to do to link & sync my carbs correctly

Click to expand...

Yep...

Re: Merc 115 acceleration proplem

bassrascal02 said:

..............After working with the low speed idle screws on carbs 1 & 2 ................so I tried the mix in gear. Engine kicked into gear a little hard ............but then when I tried to jump on the throttle to check a simulated hole shot the engine bogged and shut down. ............

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Idle mixture MUST BE adjusted to BEST idle IN GEAR, IN the water, PLUS an additional almost 1/8 turn to provide the additional fuel necessary for acceleration.

Two strokes do not have an accelerator pump to provide the additional fuel for acceleration.

Granted, the 2 + 2 system does have an accelerator pump HOWEVER that is only connected to the two LOWER cyls.

Your current adjustment is almost a quarter turn too lean. Best get back on the water and reset as spelled out above.

Do you have a copy of the service manual? Re-read the carb adjustment section a couple more times, take a couple opf notes to help remember, then go for a ride with your screwdriver.

Re: Merc 115 acceleration proplem

CharlieB - I do have the service manual and I tried to follow it best i could in the garage to set the Throttle link and the oil linkage along with all other idle screws. But I guess i was not clear on the must be in gear when setting the low speed mix...but that makes perfect sense. So am i correct in saying that the main contol I have over the mix is the idle screws on the top 2 carbs? Is the "surging" coming from the top two being too lean and the bottom two getting a normal mix after the accelerator pump kicks in?

I would have had a better test run but the wind was blowing 25+ down here yesterday and i was not about to get out on that kind of water without a proper test run of my current mechanic work.

I really appreciate all the help... it says Cadet by my name for a reason...learning as i go.
dr

Re: Merc 115 acceleration proplem

bassrascal02 said:

........ So am i correct in saying that the main contol I have over the mix is the idle screws on the top 2 carbs? Is the "surging" coming from the top two being too lean and the bottom two getting a normal mix after the accelerator pump kicks in?. ........

Click to expand...

Correct, idle mixture is finalized while IN the water and IN gear.

Done on the hose try adjusting to 'best idle' then further open 1/4 turn, that should get you pretty close. Once on the water in decent conditions, readjust to best idle in gear, then open both idle mixture screws 'almost' 1/8 turn, test acceleration hole shot, ANY hesitation add more idle fuel mix just the wide of the screwdriverblade slot and retest holeshot. Repeat to perfection.

Re: Merc 115 acceleration proplem

Thanks CharlieB. I'll get back out on the water and fine tune soon as I can...