93 evinrude 115 again

chopperguy

Seaman
Joined
Jun 18, 2011
Messages
66
Just got this thing back from a partial rebuild. Replaced bad Piston and broken rings. Also replace 3 other piston rings because they were badly carboned. Mechanic took me on the lake with it. Ran great, about a 20 minute ride. Took the the boat home proceeded to flush the motor. Now I am getting a loud cough from the exhaust. It subsides at higher rpm but at idle it stops the engine. I've been through so much with this boat I am about ready to sell it.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
You may be hearing a "lean sneeze". The engine will seem to miss every few rpm's. Actually not an ignition problem. It's likely running lean at idle. When that engine idles, the carb butterflys are closed. The air passes thru the small hole in the butterflys. That small amount of air draws fuel from the idle passages-only during idle. If they have any debris in them (possibly from lack of annual winterization) the engine will run lean at idle and will seem to have that lean sneeze. It can be severe enough to kill the engine. Once you crack the throttle just a little, the engine draws fuel from the mid and high speed jets-probably will run just fine at higher rpms. So, to fix the idle problem, you will have to overhaul/clean all the upper carb body passages-paying special attention to the idle passages.
 

chopperguy

Seaman
Joined
Jun 18, 2011
Messages
66
Just went through the carbs even though the mechanic said they did it. Only thing I noticed were the floats were set different. One was not parallel to the carb body but slightly higher meaning less fuel. Going to run it later will let you know. Thanks.
 

chopperguy

Seaman
Joined
Jun 18, 2011
Messages
66
So the cough is not as bad now. Doesn't stall the engine at idle and is less frequent. Cough is less dramatic and only occurs every 5 to 10 seconds. Still noticable out of the water but maybe not in the water. I am not satisfied. Didn't do this before this mechanic worked on it. Any more opton for me?

For reference here's whats been done to this outboard. E115TLETS
New ignition system except coils and timer base
New piston rings and #3 piston
New thernos
Carbs cleaned
No vro new standard fuel pump
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
You can get a cough to the engine if it is slightly out of time. Recheck the sync and link and the idle timing. If that carb butterfly/timing relationship is off, it can sneeze-even if the carbs are perfect.
 

chopperguy

Seaman
Joined
Jun 18, 2011
Messages
66
Thanks for your help. Do you have a good reference for checking the timing and linkage. I do not have a manual.
 
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