Logo
FULL SITE MENU

2002 Mercury 75 hp ELPTO Main Jet Question

yzf125

yzf125

Contributing Member
Hey guys, I am just wondering why Mercury put a smaller size jet in the top carburetor and same size for mid and bottom on my 2002 Mercury 75 hp ELPTO ??

The parts chart shows this also and I just want to know the reasoning behind this. Just doesnt make sense to me :confused:

.052 - Top
.054 - Mid
.054 - Bottom
 
Think that's radical, they went .072/ .078 in the earlier triples (with two carbs).

The upper cylinder apparently leaks fuel down into the lower ones, which enrichens them.

Jeff
 
If that is the case, Seems odd that the manual start non oil injected model of my same motor has all the same .052 on all 3 ?? Just doesnt make sense to me.
 
fastjeff,I was thinking that was the answer, I was afraid of giving erroneous information, I had originally typed in "nature of the beast"
 
Does the oil bleed system push the oil from the bottom of the crankcase up into the upper intake port? There is fuel mixed in the oil.
 
My plugs are all clean with zero carbon like they are brand new installed and they been in there all year, would it hurt to replace that smaller top jet to match the other larger 2 ?
 
The engine is running good, are the plugs are all burning nice and clean with toasty brown insulators. Too many people try to make these engines run better when they are designed for high performance. If it does not have any problems it does not need to be fixed. If the top plug is burning lean by all means increase fuel up a size but if the plugs are the same color dont change anything.
 
They have no color, look just like brand new plugs and been used all last season. I do have a very slight surge hesitation during full WOT not all the time though..
 
Back
Top