Center mount HPMX 40 Help!!!!

[dan.a62291]

Okay, I know the first thing that most people are gonna say "EMPI is garbage". But, I'm a baller on a budget so try to leave that part out. I know there are tons of post about the Weber and HPMX on this forum, but I have yet to find the help I need.

So, I'm having the worst stumble from acceleration to WOT sometimes the stumble is accompanied by popping from the Carb. However if I slowly open the throttle all is good.

Additional problems. I cant do the best lean idle procedure because when the idle speed screw is 1/2 turn out the engine wont run at all. it needs to be at least 1 turn out to keep the engine running.

Info.
1641
HPMX Center Mount 28mm vent. 125 main, 180 air, 47 idle. F7 emulsion tubes (I live at 6000 feet)
1.25 rockers (not sure if that is relevant)
SVDA distributor set at 30 degrees full advance.
Valve lash is at .006

Ive tried everything from 120 to 145 mains, 45 to 60 idles, F11 and F7 emulsion tubes. I've played with all the adjustment i could with the accelerator pump.

I checked the spark plugs and they are black, from what I read that means that the mixture is too rich, so I don't what to do anymore.

PLEASE HELP.
[/b]

[66brm]

Do the throttle plates have holes in them for use as a single centre mount
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Did you set the float level? To what?

What is the fuel pressure?
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[dan.a62291]

I'm not sure about the throttle plates. I'm at work so I'll check when i get home tonight. I'm pretty sure they are drilled though seeing as this was a center mount kit.

Fuel pressure is at 3psi

I haven't messed with the float at all. I don't really understand how to do so or the relevance of it.

Also, where I live at temps have have been in 30's. I thought this problem could be caused due to my lack of manifold heat risers. So I installed heat risers and routed one through to the collector. I also bought the Weber manifold that carries the heat to the base of the Carb. None of this made any difference.

John, I'm the one who emailed you a few days ago and ordered the F7's and the Weber Manifold.

[modok]

manifold too big,
you need manifold with 29-30mm ID for the tiny engine.
I'm not counting, but this has been asked and hundreds of times now.

[dan.a62291]

So the Carb is drilled in the throttle plates.

I'm not sure what you mean that the manifold is too big. there is only one manifold offered for center mount Weber IDF 40.

Also I'm aware of the amount of posts on this. like i said, I have yet to find anyone with this exact problem.

[modok]

Had some real good ones winter of 2010 but the search won't go back that far.
try this one, and the link in it to the one before that.
https://www.thesamba.com/vw/forum/viewtopic.php?t=676429

Also I feel it is important the venturi should be 86-100 % of the cross-tube size, although it is a bit strange, it does work.
Logically with an "isolated manifold" the velocity in the cross-tube is directly limited by what the venturi can flow, because they are directly connected.
If empi supplies 28 vents with a 35mm ID manifold that does not make any sense for any purpose, except selling jets

[dan.a62291]

So, I read through that post and the biggest takeaway I could get from that was maybe my Manifold ID needs to be a restricted... I hope that's not the case seeing as i just spent the dough on this bad boy

https://vwparts.aircooled.net/Deluxe-Centermount-Intake-Manifold-Kit-Weber-IDF-p/99004.315.htm

[modok]

Money cant buy love

[[email protected]]

Make sure your 30 degrees total advance of ignition timing is WITH THE HOSE OFF. Should be around 8 BTDC at idle, hose on or off shouldn't change the timing.
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It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

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[slalombuggy]

[dan.a62291]

Timing is set with the hose off.

First thing tomorrow morning I'll recheck timing and set the float level. From what I was reading I need to set it at 10mm. If that is incorrect someone please correct me.

I'm loving the input and help so far, thank you to all those that are responding.

[dan.a62291]

Here is a video if it helps out.

https://youtu.be/1ZIriQI9rs8

I checked the float level. it was set to 14mm so I adjusted it to 10mm. It made no difference.

[modok]

Most carburetor problems are not carburetor problems, that is why you can't fix it.

[dan.a62291]

Dude, I don't know what else to check.

[modok]

the manifold and aircleaner I see in the video DON'T WORK, they are wrong.

read what I said in the links and do that. Get a CB manifold, install smaller tubes, you need 8" of clearance above the venturis for spitback, so raise the airfilter or get a airbox, and try it again.

You cannot "jet" a carburetor, until you install the carburetor correctly, both the thing above it and the thing below it have to work right before IT will work right. it's a system. We can talk about it from the inside out, from the outside in, based on HP, based on CFM, basedon flow dynamics, whatever you want. But don't ask for all of the above please, ok?

If it doesn't work, come back and say so!
The worst of it is 70% of the time, guys ask these type of questions, get 10 different answers, they never come back and say what worked and what didn't.

[dan.a62291]

So the problem is that I don't really have the cash to try all these things. I can maybe sleeve the manifold. But, I can't afford another one. As far as the air cleaner, wouldn't just taking off the air cleaner simulate a raised air cleaner for tuning purposes.

Here are some things I got thinking about.

I just put on new heads, cylinders, pistons, and rockers. would any of this cause this problem?

Also I think it has 85 octane in it right now with 10% ethanol, Does that matter?

[[email protected]]

First off, the idle is way too low. Try 900-1000.

Second, is the carb base getting hot? Pictures of the preheat tubes? If they run to the 2 and 4 primaries, THAT IS A PROBLEM. You need to route one of them to the collector, or put a negative scoop on one of them in the header primary to pull the heat through the intake.
_________________
It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[slalombuggy]

I ran a single 44 on that same manifold and air filter on a 1776 and it worked fine. I didn't have any preheat tubes either.

When you drive the car are you that aggressive on the throttle? Fully closed to WOT in a second is pretty aggressive. Take it out and drive it and see what it's like.

brad

[dan.a62291]

Okay, so before you look at my wonderful job, just know, I'm not a welder/ fabricator. I'm just a dude who wants a baja bug.

I did take it on a test drive and that hesitation makes it worthless unless I go to about 3k, RPM then release the clutch

I think this is how you insert pics, haha