Question about Merc 2+2 enrichner

[sutor623]

Buddy has a Merc 2003 2-stroke 115ELPTO. Starts pretty well, but sometimes gives him a hard time. It is his first boat so I am going to the lake with him to give her a go. I have 2 questions:

1.) Does the enrichner actually squirt fuel into the carbs or does it simply open a valve so that when you turn the key the fuel runs straight in?

2.) The last owner had the carbs rebuilt just before selling (he is also a friend), but the motor studders during idle. He told me the shotty mechanic never even took the boat to the water to tune it under load. From what I understand, the top two carbs are the only ones adjustable being a 2+2. Is #24 in the picture the idle adjustment screw? Thanks in advance fellas!!

 

[flyingscott]

You need the factory manual for that motor no way around it. Try this for starting push the key in hold for 10 sec then start.

 

[racerone]

The enricher does NOT squirt fuel on those.

 

[sutor623]

Thanks racer for clearing that up. The top carb was adjusted about 1/8 of a turn too rich so when i foindnthensweet spot it idled so much better

I also figured out that he was enrichening the engine even on a warm start. Overly rich upper carb and too much priming were the causes of his issues.

 

[CharlieB]

Being a two stroke the idle mixture must be adjusted slightly richer than 'Best Idle' while IN gear and IN the water to give the additional fuel necessary for proper acceleration.

The bottom two carbs do not have idle circuits and these cyls do NOT fire at idle. As the throttle is opened there is an accelerator pump that gives a small 'shot' of fuel only to the bottom two cyls to begin firing,,. Once the throttle plates are opened air flow begins pulling fuel for the lower cyls.

Everything MUST be adjusted exactly as directed in the factory service manual for the system to perform flawlessly.

 

[sutor623]

Hanks Charlie. She is coming out the hole real strong and he is real happy with the performance now. I guess if he complain of anything in the future ill tell him to get a service manual if he wants me to mess with it. Thanks again for all the advice guys.