44 HPMX carb problems

[milleracing02]

I have a set of dual 44 HPMX. They are on my 1914 with stock heads. They ran fine for the first 500 miles and now i am having an insue with them. They run GREAT at high RPM and when i jump on it. But the motor is not idling. To me it sounds like one carb is not working correctly. I have adjusted each carb but the end resolt is the same......... And help woul dbe great (short of selling them and spendng the extra money for Webers)

[Max Welton]

Plugged an idle jet, maybe?

Max
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1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836

[dubsquared]

On mine, one of the nuts that holds the inlet horns on had rattled loose and fell into the air jet area. Was really messing with the idle as half the opening was blocked.

Just pop the filters off and have a look to make sure nothing is in there.

Mine always worked perfectly aside from that, which was my fault anyway.
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65 hp air-cooled, now with 100 hp
800+hp water-cooled
Both VWs...

[milleracing02]

I have already look down inside the carb and there is nothing there that should not be. it almost sounds like i have a cyc down but when i pull the wires each cyc drops the same. So i am mistified as to what the heck is wrong. When i get home tonight i am going to tare the carb down and blow out all the jets and other locations to makes sure its clean..... I dont have to worry about crap in the gas as everything is new, from the spun alm fuel tank to ALL the fuel lines and elc fuel pump into the carbs.

Its just driving me NUTS

[Das Dragon]

Did you clean out the carbs when you took them out of the box before you put them on?
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[milleracing02]

Yup with carb cleaner. The only thing i did nto clean out was the inside of the fuel tank.....And my filter did get a few things but i have changed that since too and nothing else in there just clean gas

[Max Welton]

Come on guys, if they worked fine for the first 500 miles, it wasn't anything he did on the initial setup.

Pull the idle jets, spray them with carb-cleaner then blow them out with compressed air. Replace them and see if that makes a difference.

Max
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1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836

[milleracing02]

Thats what i am going to do tonight. Plus i am going to clean and blow out the rest of the carb as well just in case. Then cross my fingers and hope it works so i can drive the baja to the VW Panic on Sunday.

[milleracing02]

Well funny thing. Last week i did the normal new motor thing and re torch the heads and stuff and re adjusted the valves...... My problem i found out last night was my valves tightened up again well pass 0 lash....... can any experts tell me why after adjusting the valves the would with in a few days go tight on me again?

Readjusted the valve and runs like a champ again...........
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70 VW bug
72 Squareback
VW turbo sandrail

[Dale M.]

Umm... Something was not tight, or motor was warm when you adjusted valves....

Funny how some truths come out later... "motor ran fine for first 500 miles then started missing"....... Supposedly tweaking system can cause more grief that it cures.... ALWAYS double check last work done on motor rather than assume some sort of non related problem...

Dale
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[milleracing02]

Well yes but it did not start running bad until 2 days after i retorch and readjusted the valves... So would it not stand to reason if I did not tighten ALL of the valves it would have ran rough at that time?... that is why it confused me.

So Dale please tell me how 2 days later and say about 120 miles the valves would tighten up? ALL of them tightened up NOT just one and the left side more then the right side.

When I did my adjustments the motor was cold sat all night long before wrenching on it and it stilll tightened up?

I have been wrenching on VW's since i was 14 which is about 26 years now and this has never happen to me....... BUT by no mean am I an expert and that is why i was asking..... for help to understand......
Thanks
_________________
70 VW bug
72 Squareback
VW turbo sandrail

[Max Welton]

I'd check them again real soon.

Max
_________________
1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836

[milleracing02]

Thats what i am thinking... but still never heard of this happening before.....PLEASE someone tell me its happen to them before..... at least that would put my mind at ease for the most part....

But when i did adjust them i did it by the book like i always do...... motor was cold. set them on the comp stroke. Then i even turn the motor over a few time and double checked them to make sure they were set at 6.
_________________
70 VW bug
72 Squareback
VW turbo sandrail

[Max Welton]

The only time I've had them tighten up that quick, I had made a mistake adjusting them the previous time. Some people keep a log of how much each valve needs to be adjusted each time. Easy to spot trends then.

Max
_________________
1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836

[Dale M.]

[Machinist]

I purchased a set of 44 HPMX carbs for my new 2276 build and have found some problems that I would like to share with the group. First problem was fuel running down the throat of #1 with some leaking around the throttle shaft and some around the throttle plate to the combustion chamber. I tried all the normal fixes such as float level, bad needle and seat, bad float, too much fuel pressure, fuel tank mounted above level of carbs, etc. Finally found the problem. There was porosity in the bore behind the venturi. A couple of the pitts were right at the side of the jet stacks and would allow fuel to leak into the throat. I contacted the seller and they replaced the carb. Next problem was with the replacement they sent me. For some reason I could not adjust #1 idle mixture. The plug was burning very rich and even completely closing the mixture screw had no effect on idle. The mixture screw on #2 was less than perfect but not as bad as #1. Again I tried all the common suggestions but none helped. I knew the problem had to be below the throttle plate as I was only 1/2 turn on throttle stop screw. Finally found it. I removed the spring from the mixture screw and lightly seated it. Poured liquid soap around the seat from inside the throttle bore and blew low air pressure from the vents in carb top. The brass idle mixture seat was leaking around the outside into the bore. Looking closely with magnifying glass shower a gap slightly off center between the brass seat and the aluminum throttle bore. Looking from the outside where the mixture screw threads in it appeared that the seat threaded in as there were slots machined into the brass seat. I know that some of the Italian carbs use a replaceable seats but these would not budge. I didn't want to wait for carbs to be mailed back again so I squirted some loctite around the brass from the inside and after that dried took a toothpick and put a very small bead of JB weld around the jets of both carbs just to be sure. The carbs respond perfectly now and the motor runs better than it ever has! I'll add photos soon.

[Dale M.]

I would throw this one back directly to EMPI with a little whine about the quality control of their manufacturer...

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[slalombuggy]

I too would send it back. The only way they are going to stay on top of their QC is to keep having to replace bad parts sent to customers. Ive had good luck with their carbs only a couple of small issues that were easy to fix. If they dont know there's a problem they cant do anything about it.

brad

[Machinist]

The carb with the porosity was sent back.

[slalombuggy]