rich or lean

[muller2357]

how can a guy determine if a cylinder is running overly rich or lean
i have a 96 venom 200 and info as it relates to this would be great but also just in general

[Todd D]

run it and check the color "read" the plugs. White means lean, paper bag brown means perfect and dark means rich.

[muller2357]

i ve heard "read the plug" before
i just wasnt to sure what i was looking for but that helps
we are talking about reading the insulation around the center electrode
right?

i have a stock motor and right now they look "paper bag brown"

say i was to make modifications to the motor and then do research to determine what size jets to rejet with
you would then put a fresh set of plugs in make some runs
and then read the plugs

am i on the right track here

[olmo40]

Define your Mods ? Some will need rejet some wont ,where are you at now size wise ?

[Todd D]

You are correct about the plugs. If you safely can while your running the motor pull the kill switch and then read the plugs.

[wrechin2]

Like olmo40 said, post what you have done but......


Remember you will need to run it there for a few minutes to let it burn off the fuel and let the plugs actually change colors.......

I do a quick WOT burst for about 15-30 seconds and kill the engine. I then look at the piston tops. If they still have some wet spots on them toward the exhaust, it will be fine to run at for a few minute at higher rpms to let the plugs actually change color. If they are dry, I know the out come may not be good to run it hard for several minutes. Alot easier to jet down than to rebuild.....Just my experiences.......:cheers:

[Jay Smith]

Read piston tops: If your rig can make a WOT pass and be killed clean ( At top speed safely) do so .. I use a dark towel to shield outside light . Roll # 5 piston to BDC ( Bottom dead center ) next with a bend-0-lite with a towel blocking outside light look at the intake side of the piston ( towards the outside of the block ) if the fuel wash is wet the distances of a Quarter ( coin ) or more your safe and just about correct. If the wash pattern is the distances on a dime or less you might better richen up..

This has worked for me jetting at the track at different geogragphic regions to dial in for optimal power , along with the help a Kestrel 4000 weather station, I have been suggesting this method for 14 years in texts like this one on many tech forums as well as verbal assistants on phone and at the races...

Aways remember most 2 cycles make their MOST HP 1 point above detonation ( piston destruction ) but thats too close for most recreational engines . Jet a bit rich and be safe the extra power that can be picked up by going to the edge is not worth the repair bills and time off the water if the gas formulation, loads and or weather conditions change and the motor now demands more fuel thats not there ..

Jay

[muller2357]

thanks for all the info guys this forum is great

i have not made any mods yet
im actually looking for a mid 90s omc v6 looper
that i can use as my play motor
im an auto tech that bass fishes on the weekends
cant leave well enough alone but my 96 venom runs just fine on my
boat and i dont want to mess it up
if i get another one i can play with it and see what works but i know
one of the most dangerous things is to run lean

thanks again for all the help

im sure ill have more questions like what mods you guys like to do
and things about jet sizes