2.4 runs rich at idle helppppp!

[Reaction19]

i have a slightly modded 2.4 chrome bore has 155psi on all six holes and has had the chest cut out 5petal reeds. has wh30 carbs and is missing two backdraft jets should i remove them all??? also when idling seems to be a bit rich how do i cure it other than that its pretty solid. no problems so far just a little tweaking thats all. has i believe 84's or 86's on the mains is it rich or lean, also this is a motor thats gonna be strung out at every chance and for long long periods of time so its gotta be a tad on the safe side. i use good oil and gas and dont mind changing plugs often... thanks in advance.....

[David Borg]

I would go up on the idle jets, most probably you have .046 . Try .050 and go from there.Also make sure the check valves that attach to the bleedlines are working properly.

155 psi is on the high side to use pump gas so either running a richer mix or backing the timing might save you from detonation.

Make a short WOT run and check the plugs colour , they should be dark brown. I like to use B9HS for plug reading .

Good luck

[T-REX]

Yup, what David said!!!....U also kan kick up tha idle time'in a lil bit...It will help burn extra fuel in tha cyl's......Tha check valves would be my start'in place!!

[sschefer]

Back draft jets aka economizers are there at mid range and designed to reduce atmospheric pressure in the fuel bowls. They are supposed to help save on fuel consumption. That's all they do so if you don't want that, you can pull them. They aren't supposed to affect idle or WOT but you how that story goes.

[WATERWINGS]

Yup, what David said!!!....U also kan kick up tha idle time'in a lil bit...It will help burn extra fuel in tha cyl's......Tha check valves would be my start'in place!!

Thats my problem....I don't have ANY check valves on this 2.4...no bleed lines either.........

After I idle 600 to 800 feet thru the no wake zone......it will barely take off when its cold.....

I went from .050 to .046 idle jets, and I think I need to go back to .050's

[Reaction19]

i have bleed lines and i can see them transferring fuel. timing i was told is at 23* full advance. i have the idle timing pretty advanced it idles around 1000-1200 on the hose but the same when in the water it doesnt go down any so i just start it in gear. only two cyls have the back drafts out 1and 6 also the backdrafts are.096... and i looked good at the carbs and they are wh39's. what should i do now that i have given you some more info.

[wrechin2]

Thats my problem....I don't have ANY check valves on this 2.4...no bleed lines either.........

After I idle 600 to 800 feet thru the no wake zone......it will barely take off when its cold.....

I went from .050 to .046 idle jets, and I think I need to go back to .050's

In case you don' know......That is the purpose of the check valves. They remove the accumulated fuel that gathers during low rpms. When you stab the thropttle it is initially flooding the engine. If you don't want it to go into the cylinders, run them into a common hose and back to your tank.

Remember the larger the idle jet, the leaner the mix. They draw in air only and create a restriction. The less air that passes, the more fuel is drawn out of the bowl.

[Reaction19]

wrenchin im not follwing! what should i do then????? i understand the bleed lines purpose but they are working my problem is it smells rich at idle doesnt bog or anything just seems rich compared to my 2.5 200 which had wmv5's with 82 mains on top and 80's else where. those carbs had air/fuel mixture screws on the side as to where these dont. also after a hard run these carbs seem to have dumped fuel out of them like if theyre fogging the inside of the cowling. my wmv5's would do that without velocity stacks and these dont have stacks on them. should i put them on to keep this from happening??? once again thanks for the advice.

[wrechin2]

I was replying to waterwings...... If you feel that it is rich, go larger on the jets as stated before. Larger jet= leaner mix on the idle circuit.

[Reaction19]

go bigger on what jets


do you mean the air bleeds

[wrechin2]

Yes, the air bleed. They are located at the top on the side under the brass 7/16" bolt. The bigger the jet, the leaner the idle circuit.

[Reaction19]

what about the jets in front of the carbs whats the deal with those???

[wrechin2]

Those are Vent jets. If you look at the carb while apart, there is a passage going to the bowl. Here is a description for you.

[Reaction19]

ok thanks wrenchin

[wrechin2]

No problem! Here is a detailed operation of the Vent jet circuit AKA backdraft circuit. It works the same on the WH as it does on the WMH. Most of the time people remove them to richen the mid range just a tad. Some carbs have none from the factory and some have all except for cylinders #2 and #5. I will post a list so you can see all the variations.:cheers:

[wrechin2]

Here is the list of jet sizes for MOST of the WH carbs. I have had a few that are not on this list. :eek:

[Reaction19]

thanks again. yeah my wh39's are missing two backdraft jets. i believe its 2 and 5. should i just remove them all will it be beneficial in anyway???