Merc 115 carb.30hrs,hot start and stall problem

MORRY

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Cold starts ok on choke and throttle lever up, idles around 1000 when lever down,no stalling when gear engaged.Starts easy again without throttle if motor turned off after warm up. No problem apparent when high speed running on water for say 7 miles but gets hard to start again after stopping motor . The small throttle lever has to be hard up to get it to start again.It can take 3 - 4 or more turn overs before start. When throttle put back down and the revs reduced to go into gear the outboard stalls out. I have to try and get into gear before the revs lower by quickly dropping the lever and engaging gear fast. I may stall out perhaps three or more times before getting under way! Any thoughts much appreciated on this almost new Merc?
 

CharlieB

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Re: Merc 115 carb.30hrs,hot start and stall problem

A few questions come to mind.

After running, do you LEVEL the motor before turning it off? Do you give the motor a minute or two if idle time to cool down from hard running?

If leveling before the restart are you checking the primer bulb to ensure that the now-level carbs are refilled?

How much time has past before restarting? Has the engine cooled enough that you need a minute of moderate idle to re-warm the engine?
 

Laddies

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Re: Merc 115 carb.30hrs,hot start and stall problem

2 things, are you talking about a 4 or 6 cyl 115 and have the carbs been adjusted when warm, in the water and in gear or just set a the basic setting?
 

MORRY

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Re: Merc 115 carb.30hrs,hot start and stall problem

Hi, yes the outboards in the level position and I usually motor around around for a while in low revs looking at my Fish Finder. I do make sure the fuel bulb is primed before starting and the trouble seems to be while the motor is still pretty warm . Main thing is that I have to use throttle hard up and sometimes choke to restart.
 

MORRY

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Re: Merc 115 carb.30hrs,hot start and stall problem

2 things, are you talking about a 4 or 6 cyl 115 and have the carbs been adjusted when warm, in the water and in gear or just set a the basic setting?
Hi, it's a four cylinder. I'm almost sure the settings would be basic. it was bought as a 2005 model on my new boat here in NZ. No the carbs have not been adjusted on the water as far as I know!
 

Laddies

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Re: Merc 115 carb.30hrs,hot start and stall problem

You might try running some mercury quickleen or other carb cleaner through it and then adjusting the carbs. Don't use some of the fix all stuff as you need a carb cleaner.
 

hkeiner

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Re: Merc 115 carb.30hrs,hot start and stall problem

No problem apparent when high speed running on water for say 7 miles but gets hard to start again after stopping.

You are probably on the right track troubleshooting for possible fuel/carb related causes. However, I would suggest that you also check for adequate spark on all cylinders when the motor does not want to run well at idle. It is possible that the low idle ignition circuit is failing on one cylinder from the extra heat generated during a long run.

Just my thoughts...
 

CharlieB

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Re: Merc 115 carb.30hrs,hot start and stall problem

Most of the 4 cyl 115' are in the 2 + 2 family

The idle on the top 2 cyl's only, the bottom 2 cyl's are only along for the ride until the throttle is moved off an idle.

Idle mixture screws are NOT even installed on the bottom carbs.

When idle quality suffers on a 2 + 2 then it's usually a sign that the carbs need attention, HOWEVER, ALWAYS look at your spark plugs to get an indication of combustion quality, AND TEST SPARK to be sure there are no ignition issues.
 
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