Dies under load

1641 dual port single solex mech fuel pump new filters. Idles like a dream and can rev to 3000 sitting still no problems drive less than a mile and it dies under load push in the clutch starts right up and will drive another half mile or so and repeat.
Any suggestions

Richard

Fuel pump unable to keep up with demand? Clog in the fuel system somewhere?

It will rev and sit at 3000 rpm with no stumble it's just doing it while under load. If I change out to an electric fuel pump what do I need to do to the Mechanacil one? seal it of or anything?

Possible flooding? Can you play with your mixture to lean it out a little?

Richard, a lot of things could be the problem.

Let's start with fuel... Replace the fuel filter/s If that doesn't solve the problem then replace the fuel pump (if it's a mechanical pump, most are junk) Empi, CB, Cip1 etc. make a block off plate to cover the fuel pump hole ( http://www.cbperformance.com/catalog.asp?ProductID=578 ) if you go with an electric pump.

Personally, I like the CB performance 3193 rotary pump that is pre-set at 3.5 psi ( http://www.cbperformance.com/catalog.asp?ProductID=577 ) If you go with an electric pump, mount it as close to the gas tank as possible with a filter before the pump and after the pump.

Other issues could be a weak coil that breaks down under load. If you have points, they could be worn or not set correctly.

More than likely, it's a fuel delivery issue.

Larry,
Both parts ordered, thanks for the input I guess the Madness never ends.

By the way Merry Christmas to all of you.

Richard

Larry-any special filters recommended for use with rotary pumps vs. mech. ones? (IE, flow rate/restrictions..?)
Thanks in advance and have a great end of year! SS

Just about any filter will work. Generally, I use a metal in line throw away filter available at just about any auto parts store.

The electric pump doesn't flow that much fuel and at 3.5 psi, just about any filter will work. My only suggestion is to NOT use those tiny plastic filters! You know what I'm writing about!!!, the kind that have a clear outer plastic housing with a pleated paper inner filter. These are generally sold with a graduated "IN" and "OUT" that allows you to cut the stems to match the fuel line inside diameter. A whole bunch of these are generally seen on VW's

They have the potential of melting and causing an engine fire.

Yep, replace the filter first and try it. When mine clogged it would run on level ground, but when I tried to go over the mountain, it sputtered and died.

~WB

I have 2 new filters installed one below tank and 1 after fuel pump. Do not think it can be filters have less than 300 miles since installation.

Standard tank? ; bad internal scavenge filter a possibility here?

If you shut it off and let it sit for a few minutes does it start and then run for a short time ? If so, go for the in tian sock filter. ~ALan

i had a B&S gas engine on mower. the gas cap had a vent hole in it and if it got plugged the mower would run for a few minutes and stop because of the vacuum. incorrect gas cap?

-2 for key board error... t - a - n - k

Possible that you have rust acumulation on the inside of your gas tank? On mine, the internal crap accumulation was blocking the internal screen at the tank outlet. This in turn limited gas flow, even though all my external in-line filters looked clean.

Sounds like it wants gas and is not getting enough. Happy hunting.

No filter in tank, both of the others are realativly new took them out anyway and replaced them today to see if one was bad starts instantly once it dies even while still rolling. RPM's have to get to 0 first won't keep running. Sitting still it will rev 3000 to 3500 RPM no problem not just run up but steady and smooth for several min no skips any thing just does it under load. Replaced the points with electronic a year ago. I guess I can get a new coil as well they are not that expensive. I do have a new vent hose on the tank just 4 foot to run under the car I'll take it off for now and see if thats it.

Larry,
Your folks at CB said they were behind on shipping by several days as of this morning my parts are in LA (wish I was) on they way to me top notch bunch over there.
On replacing the coil, one of the blue Bosch ones or is there an upgrade I should look at?

Richard, FYI
I have no association with CB Performance

Richard, Been there done that. I get a lot of stuff quicker from here:

http://www.peekperformance.com/shop/index.php

http://acmecarco.com/store/index.php?main_page=index&cPath=82&zenid=30716f99eec5783557e971d80c6d9e4b

~WB

Some others here probably know this one better than me, BUT -

Is it possible that the float bowls are set too low? Engine revs easy in neutral cause you don't need much gas to do that. Drive it a mile under load and you suck the bowls dry (thats about how far I get if I forget to turn my fuel shutoff switch "on"). Put it back in neutral and the bowls will recover when you re-start the engine. Then everything repeats?

OK, even though it's Christmas Eve and ALL of us should be gathering with friends or, even better, family, I'll ask this simple question......

Did it use to run OK and this is something that has manifested itself recently? Or is this something new???

If it's something new, then pay attention to the info posted above.

If it's been there all along, well......that's a whole new ball game!

Merry Christmas, Y'all!

See you next year!

Gordon
The Speedstah Guy from Beaufort

Check the fuel line from front to rear (been there, lived it)

Dave Klipfel's idea makes a lot of sense if it's a problem that's been around for a while. Float levels aren't likely to change on their own. It does sound like fuel flow can't keep up with demand under load, but it ok the rest of the time. I'm still thinking fuel pump of a clog somewhere.

Richard-this a single (1) carburetor engine, correct; what Solex model is it?

This is a new problem 34 pict 3 solex. last 300 or so miles no problems since oil change and tuneup. Put in new fuel filters as a matter of course have replaced the new ones in case one of them had restricted flow had also put a vent hose on it about 4 foot long have taken it off as well in case vent hose was causing it. Have elec fuel pump on the way. Open to any other ideas.

Gordon, I feel like a lot of these folks should be friends if not family maybe not Vince but you know everyone has some type of skeleton in the closet.

Richard

OK-pre read this stuff, although may apply more to an older carb than new:
http://www.aircooledtech.com/34pict3_modification/

http://www.german-pride.com/Joomla/index.php?option=com_content&task=view&id=36&Itemid=70&limit=1&limitstart=1
(I think Solex is now "Kadron"-could be wrong but see if there's anything that could help regarding setting up the carb-IF the factory setting seem wrong)


http://www.shoptalkforums.com/viewtopic.php?t=114081 (exploded dwg: scroll down to Solex 34 PICT 3)

http://www.thesamba.com/vw/archives/manuals/carburetors.php

Please ANYONE jump in as these are informational resources that I've "bookmarked" and may be confusing. There are forums associated with these links and someone may put a finger on the problem! Really good luck!!! I only wish I could come up with THE answer. Scott

I seem to recall a similar symptom as yours and it was something to do with the carb "bypass" valve; just can't recall exactly as it's been almost 30 years! Yikes!!!

Here's a couple old VW training films on carbs. The 34 is referenced at about 2 and 3 minutes in the vids pt1/2.
http://www.youtube.com/watch?v=XOxxS1EMphU&feature=PlayList&p=A80CF55BEEEB92F2&index=15&playnext=2&playnext_from=PL

http://www.youtube.com/watch?v=KWdZSr7x81w&feature=PlayList&p=A80CF55BEEEB92F2&index=17

Don't pass over Ernie's mention of the fuel lines.
If you're running rubber lines they do degrade over time, especially if your state requires "winter gas". MTBE is very hard on the rubber lines and can cause little bits to float into your carburetors.
Disconnect one of your fuel lines at the carb. If it's stiff and relatively hard to squeeze shut, it's time to change them.
Check in the float bowl for microscopic black particles.

Actually, my culprit was the stock steel line from below the tank to in front of the fire wall. It was on a '60 VW convert and clogged with rust!

When the air cleaner is off while it starts to die does pumping it continue to give fuel? or does it stop squirting ..If its not in the tank,,, Then it is ether a sticking float in carburetor that's not set correctly. OR a bad fuel pump Also IF the carb. is dry when you pull the drain plug It will also point to float or fuel pump. and thou it's not common a ca-lapsing fuel line. will also do it..

That every trick I can think of.. Rich

Parts have made it to Memphis today, should be here by Monday. I am going to drain the tank tomorrow, it has 10 gal in it then replace all rubber lines with new. Blow out the hard lines. Put on new (3rd set) filters one below the tank, then new elec fuel pump and second filter in the engine compartment. The car won't act up unless it is under load, I have let it sit and idle for about 30 min then revved it up to 3000 RPM and held it for close to 60 seconds no issues at all. Drive it 1/4 mile and it dies, stop and it will immediatly start up and drive another 1/4 to 1/2 mile and die. Will report or complain some more when I get the new parts on and fresh gas.

Happy New Year

Richard

Float bowl level too low!

What could have caused it? Put 300 miles over a week on it with no issues.

i run another fuel filter not in the engine compartment but on the other side of firewall back by the axle in case it leaks.
gas leaking on hot cylinder heads might not be pleasant.

Richard, the pump should be mounted up front away from the engine's heat. I mounted mine under the tank on the little shelf behind the right front wheel. Theses pumps work best pushing the fuel rearward rather than drawing it to the rear of the car.
I ran a line from the tank to a shut off valve ( Briggs&Stratton I got at the hardware store) to a filter, then into the pump and then to the line to the rear. Having the valve there makes it real easy to change the filter.
As far as wiring, all you need is to run a single line that is 12v switched from the fuse box or ignition switch with an in-line fuse.

~WB

what barnco said!

Weather finally cooperated yesterday and dissasembly started. Fuel pump disintegrated when I removed it. I drained the tank and with flashlight looked inside it is pristine clean steel. Replaced all the rubber lines with new, blew all the metal lines and got the pump mounted. Stil have to get the electrical done had to cut the day short. It's Mardi Gras season and I still shoot potographs (gotta pay for the toys). We have gotten close to 3" of rain since 3 AM so do not know if I'll finish today or not. I had no idea the pin could work out on the mech pump and it fall apart. Hopefully I have gotten to the bottom of my issues I have been fighting this since the Dragon. It's been so intermittant being able to drive a couple hundred miles and issue starting again. Will post once I get to drive again..

if the pin worked ots way out, where is it. bill

The pin was dangling came out on the engine case side couldn't see it.