115ETLF Tune-up & Carb questions

Popster

Seaman Apprentice
Joined
Jul 18, 2007
Messages
44
This motor would not idle properly when I got the boat. It was idling around 11-1200 rpm. I went through the shop manual and check the timing, carb pickup, carb sync, etc as per the shop manual in the order specified. The previous owner had screwed out the fully retarded adjusting screw to increase idle speed. the throttle cam control link was also off.

Before adjustments, the idle screw was ineffective, now it is controlling engine idle

I shocked the motor when I first got it (last week) with ringfree. I also took off the carbs, partially disassembled, and sprayed cleaner followed by compressed air through passages. On the sides of the carbs at the bottom were plugs that the parts diagram call drains. However, they had a hole bored in them that was plugged with gunk. I cleaned them. The rest of the carbs were clean as could be. I reassembled and reinstalled them on engine.

I set the idle needle to 5/8 turn as per the manual. I then set the idle very low- 500-600 rpm and attempted to adjust needles one carb at a time by turning in needle. I was waiting for the motor to spit or stall. Instead, I could turn needles to soft stop and there seemed to be no effect on the motor.

The motor has a "grumbling" sound to it a low idle, but does not stall and runs like a top.

Are the idle jets/passages accessed through the bottom plug in the carb? I was wary of trying to remove the very small jets. I am grinding a parallel screwdriver down to fit them- I know from my old Ford 8N tractor that it is easy to mess up small jet when trying to remove them.

Do the carbs need complete rebuild? Any tips on removing idle jets? Would this cause the rumbling/grumbling so at low idle? I'm assuming that the carbs are not right due to the lack of response while adjusting idle jets.

Thanks for any thoughts.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 115ETLF Tune-up & Carb questions

on that carb idle fuel mix is fixed by the idle air jet and the idle fuel jets. the screw just allows more or less of the mix. set the needles by the book and if everything is correct it will run.
I usually dont take those jets out as they tend to break off. just run a strand of copper wire through them and the transfer passage.
 

Popster

Seaman Apprentice
Joined
Jul 18, 2007
Messages
44
Re: 115ETLF Tune-up & Carb questions

Thanks for the reply! On my tractor I use welding tip cleaners of the proper size. Will do- would rather not take the chance on breaking jets. Many thanks!
 
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