Jetted too rich?

[SatisfAction]

2.4 chrome, tight heads 145psi, velocity stacks.

WH-34's

.076's and .078's in the mains
.070's in the idles
None in the vents.

Good holeshot.. at about 85% throttle it runs best. Once I put the pedal to the floor at WOT it is stumbly. Hitting the primer doesn't help it so I'm guessing its rich?

I previously had .064's and .066's in the mains and .070's in the idles and it ran pretty good. I wanted to jet up to make sure I was getting enough gas with the 2 liter heads but maybe jumping to .076 from .066 was too much? What do you guys think? Any suggestions?

Thanksssss

[1BadAction]

what do the plugs look like?

[SatisfAction]

what do the plugs look like?

When I got back in it was dark.. I will check them in the morning. Before I jetted up, the heads I took off previously were realll clean.. like it was running on the lean side...piston tops looked good though.

[SatisfAction]

what do the plugs look like?


When I got back in it was dark.. I will check them in the morning. Before I jetted up, the heads I took off previously were realll clean.. like it was running on the lean side...piston tops looked good though.

EDIT: Screw it, I'll get the flashlight and a wrench and go pull those babies.. BRB :D

[SatisfAction]

Plugs look good. The surfaces surrounding the electrode in the center are clean and the porcelan and electrode are light brown/tan.

[1BadAction]

you should really do a throttle "chop" and check them. if your idle mix is right on, its going to look good once you idle back to the dock/trailer and pull them.

I always just got off the throttle as fast as possible, shut the motor off coasted into the beach, jumped out in the shallows and pulled the plugs.

[SatisfAction]

you should really do a throttle "chop" and check them. if your idle mix is right on, its going to look good once you idle back to the dock/trailer and pull them.

I always just got off the throttle as fast as possible, shut the motor off coasted into the beach, jumped out in the shallows and pulled the plugs.

Thanks Jim. Might try doing that tomorrow. Problem is, I have no beaches 'round here. Might also try putting in some .070's in the mains and .060's in the idles and see how she rides. The friggan holeshot is awesome. I also had only 93 octane and Merc synthetic at 50:1. It was just sorta stumbly and boggy at WOT.. and I noticed a few times if I held it at WOT it would pull past the stumble and run fine... right on up past the confines of my 7k tach.

I know the carbs feed off the idles/vent at WOT. I have no vent jets in my carbs... could that be causing a richer condition. I can blow air through the vent in the front of the carbs and it shoots gas into the venturis. :confused:

[1BadAction]

I know the carbs feed off the idles/vent at WOT. I have no vent jets in my carbs... could that be causing a richer condition. I can blow air through the vent in the front of the carbs and it shoots gas into the venturis. :confused:

thats a question for someone like T-Rex. I never got into much more than richening it up on top end slightly and leaning it out on bottom. Truthfully I kind of miss working on my old stuff... but then again I dont miss that fuel consumption. :D

[SatisfAction]

thats a question for someone like T-Rex. I never got into much more than richening it up on top end slightly and leaning it out on bottom. Truthfully I kind of miss working on my old stuff... but then again I dont miss that fuel consumption. :D

Well I suppose when T gets back from chasing women maybe I can get an answer from him. I know that it more than likely isn't lean because hitting the primer made no difference..if it was lean it woulda run better.

[rob vaughn]

Are you sure it's "stumbly", and not predetonation???

[SatisfAction]

Rob, I'm not sure if it is preignition but I'm not positive that it isn't. Haven't ruled that out yet. My spark plugs are all within the heat range.. piston tops and heads are clean so I shouldn't have any hot spots and the engine stays cool while running. I'm going to swap in some smaller mains and see what it does. Timing is spot on at 25 degrees total. Like I said, holeshot is awesome, acceleration is good... it's just the last 1inch of pedal travel it falls flat on it's face.

[dez nuts]

It sounds to me like you are rich drop down to 72 if you have them and try that 70;s are probally okay but you might want to watch it real close i had the same problem on a 2.5 carb motor and every time i drop down a size it got better, try 72or 70 that should make a big difference the air jet should not make a difference we always run the 2.4 carbs without them the 2.5 will not run without them though, it will stall everytime you let off the throttle. hope this helps. Keys Dave:rolleyes:

[SatisfAction]

It sounds to me like you are rich drop down to 72 if you have them and try that 70;s are probally okay but you might want to watch it real close i had the same problem on a 2.5 carb motor and every time i drop down a size it got better, try 72or 70 that should make a big difference the air jet should not make a difference we always run the 2.4 carbs without them the 2.5 will not run without them though, it will stall everytime you let off the throttle. hope this helps. Keys Dave:rolleyes:

Thanks Dave. I put .070's in the mains and richened up the idles with some 64's and it runs great now. Doesn't seem to be lean... no sneezing or fuel starvation. Thanks for the help fellas. As for the horizontal conversion... it has a little more power on the bottom and mid range. The top end is a step up as well. I need a bigger prop now!! :)

[basscat39]

Glad you got things worked out. I finally got my vert swapped out today,fit perfectly just need to order my TDR reeds from Jay
Basscat

[YELLOWSS]

you are going to have big problems if you run it @ 7000 rpm's and oil ratio
@ 50 to 1!!!!!!!!!!!!!!!! it is a blessing you are running rich on the big end right now!!!!!!!!!!!!!!!!!!!!!!!

just my 2 cents

[SatisfAction]

I've always been told 50:1 was fine. Even with the vert. intake I could run 6800-7000 with no problems at 50:1. I do always have a habit of adding another gallons worth of oil to my fuel so it's a little richer than 50:1. Motor ran great yesterday.

[YELLOWSS]

50 to 1 is usually good for max of 6000 rpm's
then 40 to 1 to 7000
32 to 1 over 7000.

do a search on here jay smith, and others have discussed it before.

all your hp motors. bp, 245, 260, 280, 300 drag are 32 to 1.
some guys that spin them 9000 to 10000 even use more oil!!!

[T-REX]

SMOKE iz insurance!!........He'z rite about tha oil....I run 40:1 on all my stockies, 32:1 on modified river motas, and I run 25:1 in my lil F-1 mota...They are all juss az happy az a pig in a mudhole!!...

Satisfaction, Glad ya got ya stuff straight...I didn't see this post till ya dun had it goin ya way....Remember this about them carbs, and jets...U kan go down .002, and not make any differnce......

I guess I'll try ta exsplain....When I jet a carb, I alwayz start rich(kan heer tha 4stroke/stumble)...To play it safe, go down .002...If the stumble/4stroke lessens, rpm will pick up....then go down anuther .002...If the tach gains a few more rpm, go down agin, 002....IF the mota don't 4stroke, but stays the same(gains no rpm)...Go back UP .002...U have hit home, and are on the safe side of the fence!!!.........There iz a .002 safety margine in them ther carbs on a 2.0/2.4.........2.5 plays by differnt rules:D

[SatisfAction]

32:1 it is!! Thanks for the heads up. I also don't hold it wide open all day like some people. 7k for short amounts of time...like 10 seconds or so then back down. Ran it without the cowl yesterday while doing the tuning and the motor sounds good breathin' through the stacks. I'm thinking of propping it down to around 6600 or so. 7k +rpms on a stock rotating assembly makes me nervous! :D