ok I searched and came up with a list of possible psi to use. So heres the rundown on the issue.......Car is 1985 gsl, 12a, basically all stock, no emissions, and hopefully if it decides to work, a mikuni!

Purchased used mikuni 44phh, off ebay, seller claimed it was off a running 12a. Well when I got it, bolted it on, and it didnt run very well at all. So I yanked it off, and opened the top. Tons of white powdery stuff. You know the gasoline crsytals. WEll after complete dismantling, and blowing everything out with an air hose, and solvent. I need to do a full rebuild on it, but it was discountinued in 1995, so I am having a heck of a time finding a kit. I guess I will have to do it the old fashioned way, make my own gaskets, clean it the best I can and hopefully scrounge up another one for parts.

WEll my stock fuel pump is dead, and I was too lazy to remove it, so I bought a new pump, and placed it under the hood. Now I got gas, and a return to the tank. Tank was just cleaned, and new fuel put in. I am using all the stock fuel delivery system, plus one new pump. Well. I watch the fuel filter(also under the hood), and I see the nice pretty green premix gas flowing into the carb. Start it, HEY it runs, what do you know.

Punch the throttle to WOT, and BOG BOG DEATH.........WTF? So I start it again not using any throttle......Chimes right up... SO I screw around with the A/F screws, and get it screwed down pretty low, Im talking only about 3/4 turns from seating. WEll if I punch it now to WOT, it will go, but stumbles a bit, If I screw the A/F any lower, it bogs, any higher it bogs. If I feather the throttle a little I can get it to climb really slow for a couple seconds, and then BOOOM takes off like a rocket! So now for the test drive, after fighting with it every time I put it in gear I limp back home, to fiddle some more. Well I can get it to rap up pretty decent sitting there, but as soon as I put a load on it in gear........Bog, Bog, Bog, ZOOOOOM!, this is very annoying to me, and makes me look like a retard in front of everyone else on the road. After a few runs up and down the alley, forward, then reverse, and again. I parked it popped the hood and I look into the filter, its very low, almost like the carb just isnt getting enough fuel after a little bit of revving..........

Is it possible that the old carb is restricting the fuel flow?

Or I noticed under the car there was a metal device with lots of fuel hoses running out of it. Is this possibly a regulator of some type?

I heard it mention that the nikki runs real low, like 2.5 PSI, can someone give me a concret answer to the correct PSI for a mikuni, I have heard all the way from 3 psi to 7....So what is it? I cant find the mikuni guy I read one of his posts, and he said he loves the mikuni, and its very simple. I know I am just overlooking something simple, but forgive me, the gas vapors have gone straight to my head. I am surprised I can even type, OOOOOHHH my head is spinning!

 

I run my mikuni at 4 psi, in my 13b 4port. It does a little bogging but not much.
check all your jets, make sure you're not running to rich.

 

do you know where to buy new jets if they are too big?

Ok A/F jets that goe into the stacks, are stamped 06, under the little cover with one screw, is the air bleeds? Not sure, but the large upper with the smaller inset, are stamped OA, and the inner bleeds are stamped, 24C, or 2.4C, and the other smaller bleeds below in the corners are stamped 62.5.

 

With the condition you found the insides in, I'll be supriseed if the ap diaphram is still good. Wolfcreekracing.com sells Mikuni parts online, rebuild kits, jets and a tuning manual.

These carbs don't like beng mashed during the transfer from pilot to main circuits. Most of it can be tuned out though. When you get the rebuild kit and have it apart, post your jet sizes.

 

Ok the best way to show you guys what I am talking about is with video.......
Heres the linky........



Click here to see Video

 

Vid pretty much comfirms what I said earlier.

Your engine is runnig way too rough, have you done a comperssion test lately? You have either a stuck seal or an ignition fault.

 

ok as for ignition, I did a total tune up not even 8 miles ago. AS for compression the car ran great with the stock nikki on there. I am beginning to think I just got screwed by a previous owner, slap the old nikki on there until I can shell out the cash for a NEW OER weber knock off, and see what happens........AS is life they say..........

 

The Mikuni is a good carb, you are giving up too easy. When you cleaned it up, did you take the AP apart?

 

AP meaning accellerator pump? If so then yes, and it was clogged, I cleaned it all out the actual diagphram looked new, but it was still clogged up. I blew it all out, and there were 3 holes on the shaft, maybe I should try all 3 locations, but first I wanna get a rebuild kit from wolf creek, and try to breathe some life back into this carb. I really want it to work, not for myself, but for my brother in law who purchased the car, but I refuse to let him pay me, until its running correct!

 

Wolfcreekracing.com ....be careful this guy is a scamartist! Todd likes to recieve items on ebay, file a bogus complaint, get his refund and then never return the item! Has my carb and his money back....sweet deal huh?!

 

News to me, this is the first I've heard of trouble with Wolf Creek.

The 3 holes on the shaft does change the volume of fuel the AP pushes out.

Did you take the carb completely apart, includung all of the jets? If compression and spark is good, then fuel delivery is off on one side of the carb. Also do not over tighten the idle screws. A few members have found that they can snap in half easily.

As a side not, check for vacuum leaks.

 

[unhelpful] ....my lawnmower sounds just like that.... [/unhelpful]

...maybe you should fix up the botched fuel system first? The 12a's use an inline fuel pump already (possibly what you are referring to as "a metal device with lots of fuel hoses running out of it" under the car (near the fuel tank)? ...its fairly simple to squirm under and replace it (atleast from the looks of things, haven't done it yet... ask me next week )

Good luck!

 

i didnt read anything about a fuel pressure regulator. maybe youre getting too much fuel? id definately say you need to fix youre rigged up fuel system. its not hard at all to put the put you have in the engine bay where the stock pump was. heck, if you need it bad enough i have a stock pump, holley red, and a FPR ill sale you really cheap to help you out.

as trochoid said, it could definately be spark or compression as well. id test both of those. just disconnect the fuel system and pull each spark plug wire of the plug and hold it close to the strut tower bolts and see if it sparks. keep them attached to the dizzy and do it one at a time. make sure you dont put them back on in the wrong place.

 

take the whole thing apart again, dip it in some cleaner for a day. while you wait for your rebuilt kit from wolfcreek racing or rebello racing.... take your time and clean everything out. then but it back together with the new gaskets and seals.

RE-LOOK at the jets again, you're off on the numbers for the jets. if your main jet on the bottom is a 240, then you're way to rich.

write down all the numbers for the jets and the venturis that you see.

 

Ah. Sounds exactly like my 44PHH did. Super-sensitive accelerator, bogs down if you punch it too hard from idle or if you are flooring it in 3rd or 4th. I got a Mallory Comp 70 fuel pump and the guys at my tuning shop slapped some kind of FPR on it, then after a rebuild it ran almost perfectly. Still has a touchy throttle, and it bogs a tad now and then, but not under any circumstances where it would hurt your speed.

I have my own question here: What is a good range of jets to buy for tuning a Mikuni 44 on a streetport motor? I'd rather not have to buy a bunch of jets I don't need

 

240 must be the number, becuase the the stamping isnt the greatest. I wasnt sure to call it a 0 or not looked almost like a C. So yes then it is a 240, which is appearantly way too rich? You got any numbers on the appropriate sizes?

 

The fuel inlet on this carb has two inlets. Did you run the fuel into one side and a return on the other side? This carb doesn't have a return. Have you tried to see how it idles when the engine is up to temp. With my mikuni I run it with the choke on until it warms up.

 

Yea appropriate sizes would be great. I need to rebuild my mikuni it bogs real bad. I have been driving it for 2 years so I know about the normal mikuni bog. I drove for 1 year with the stock pump on it no poblems but it did bog. Now I have a se pump and reg.

Does the mikuni really not have a return? I have hooked it up both ways and it works both ways???
My 12a is street ported with a header and rb muffler, no cat.
What would be good jet sizes?

 

Nope it's not a return. If you hook up one side to up to the return than that means you won't get any fuel pressure and it would drive like you have a clogged fuel filter.

You've been driving it for 2 years and you haven't tune it yet? What are you waiting for?

 

Why are you running the SE pump. going boost? Also, which fpr, and what are your current jets?

 

I got the pump b/c my buddy worked at O'Riley and got it at cost with lifetime warr. I do have a TII turbo sitting around. I just got the cheepo prolator fpr, for now. I have no idea what the current jets are. I will take it appart this weekend.