carbs loading up after a nose stab

Frosty

Frosty

New York Crew
Location
Western New York
so myski runs great!! killer bottom end, throttle response and great accelleration.

I have everything dialed in pretty good except for one thing... when ever i do a nose stab (and it's only been flat water here so far) when i come out of it it feels like the carbs are either loading up or I'm getting water in them and it takes a few seconds to clear them out.

I'm running oem air boxes, which i cut to fit the ADA girdled head.

Any thoughts...

oh, and my jetting specs are (twin OEM 44 mikunis)

main 100 H 3/4 turn out
Pilot 115 L 3/4 turn out
2.3 N/S
65 gram spring

on a ported 82mm 61x cylinder, 62t cases, ADA head with 33cc domes, lightened flywheel, OEM ignition with pro-tec adjustable rev limiter, R&D intake mani, Riva reed spacer, MT VF reeds, OEM 44's and a limited chamber FPP

I had a couple of thoughts, but i am not sure if any of them would contribute to this problem:

1. I have not checked the pop-off pressure however, I am wondering, since I nose stab to the right if the pop-off is too low would that cause fuel to flood into the carbs when stabbing right?

2. I noticed that when i take the gas cap off I don't have any build up of pressure in the tank. Could my check valve be shot, and a lack of tank pressure cause this?

3. I am running a WDK Diablo hood, with the two 2" breather hoses... could it somehow be running out of air after just a few seconds of being under water?

4. could the cut air boxes, even facing the cylinder, be allowing water to splash up into the carbs?
 

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keefer

keefer

T1
Location
Tennessee
I have always had the same problem to varying degrees with all of the different flavors of Mikuni carbs that I have run over the years. Some carbs and tuning setups would do worse than others. I have always thought that Mikunis go rich if you slam the boat to one side or the other depending on how the carbs are mounted. I have found that if I run the idle a little high it seems to make it not as noticeable.
 
keefer

keefer

T1
Location
Tennessee
One of the guys that rides with us is running 46mm Black Jack carbs and he does not seem to have this problem. I am running Full Spec 48s and they do it to some degree, but not as bad as the regular 46s. I think the annular discharge for the mains on the Black Jacks has something to do with it making it not dump fuel as bad as the bomb site style carbs.
 
Frosty

Frosty

New York Crew
Location
Western New York
vomitspot said:
that guy rarely sells anything to you and hes bad about shipping too!
send me your add and ill fwd it to myself and try to shoot these to ya
Click to expand...

LOL - i sent you an email...

I’ll try ‘em out… if they work better I’ll take ‘em – if I don’t like them I’ll ship them back to you.

Maybe i should have just kept those (your) red tops... ; ) LOL
 
S

sflsurfrider

i had that problem on my square. i leaned out the bottom a little and it went away.

i cant remember if it was as simple as turning in the bottom screw or raising the pop off as to not be overcome by the massive 'choke' that the bilge area gets when the air vents in the hood are sucking in water.
 
Frosty

Frosty

New York Crew
Location
Western New York
sflsurfrider said:
i had that problem on my square. i leaned out the bottom a little and it went away.

i cant remember if it was as simple as turning in the bottom screw or raising the pop off as to not be overcome by the massive 'choke' that the bilge area gets when the air vents in the hood are sucking in water.
Click to expand...

I'l try that 1st... i'll go in a little on the low adjustment screws and see what that does. if that does not help I may change to a 2.0 n/s with a 95gram spring to see if raising the pop-off helps... if all else fails, by then i should have the black jacks in from Vomitspot (LOL) and i'll try those out.
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
hey Phil, when I got my first hood, it was used Wammer, one of his earlier designs, It did the same thing, I threw on a new hood off someone else's ski and the problem when away......... Solution, I called wammer and he took the hood back and gave me credit towards a new hood....... that corrected it.. My motor was not getting enough air, I was running a single carb setup at the time as well.
 
crammit442

crammit442

makin' legs
Location
here
Just for grins, see if your hood liner is seperating. We recently found that on one of our boats that was doing the same thing. Fixing the liner fixed the issue.
 
Frosty

Frosty

New York Crew
Location
Western New York
Big Kahuna said:
hey Phil, when I got my first hood, it was used Wammer, one of his earlier designs, It did the same thing, I threw on a new hood off someone else's ski and the problem when away......... Solution, I called wammer and he took the hood back and gave me credit towards a new hood....... that corrected it.. My motor was not getting enough air, I was running a single carb setup at the time as well.
Click to expand...

good info... maybe i'll toss my stock hood on and see if that changes things...
 
Frosty

Frosty

New York Crew
Location
Western New York
crammit442 said:
Just for grins, see if your hood liner is seperating. We recently found that on one of our boats that was doing the same thing. Fixing the liner fixed the issue.
Click to expand...

really? i'll take a look - do know that the two air hosed coming from the liner were just sitting in there, and i zip tied them together so they would not come out, but water could easily come in outside the hoses... possibly flooding over the head and splashing into the carbs (since the air boxes are cut). I have since epoxied the vent tubes.... but have not riden it since doing that.
 
Frosty

Frosty

New York Crew
Location
Western New York
Big Kahuna said:
are the tubes not glued in? If not, get some black RTV/Silicone and just run a thick bead around them.
Click to expand...

yeah, they were not glued in during my 1st couple of rides. I just glued them in yesterday... so i will be riding again without making any other changes to see if that corrects the problem. Then go from there if i still have the problem.

Watch, that's probobably my problem... and i was just being a dumbass... LOL
 
Frosty

Frosty

New York Crew
Location
Western New York
ok, i rode friday and saturday. the epoxied in air vent tubes didn't make the problem go away.

I leaned out the low speed adjustment screws a little and it's a bit better. I leaned them out a bit more... and will try it out again today. I did notice that when i pull my hood i have water splashed up on the oem air boxes so i think i am just getting a lot of water splashing up into the rear carb. I may try to fabricate a base plate and use a oem air box from a GP760 ( similar to the oem 38mm carbs)
 
#ZERO

#ZERO

Beach Bum
Location
Florida - U.S.A.
You're running racer jetting with that low pop-off pressure.

Do what you said and change it to a 2.0 & 95 gram spring but make sure you increase the main jet to about a 122.5 at the same time and the throttle response should be a lot crisper.
 
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