My first post!

Wondering if anyone can help me with a problem on my 1600 xflow engined locust.
it has a 32/36 DGV which seems to be the root of the problem.

After a carb refurb kit fitted with new gaskets, filters, clean up, needle valve float reset etc.

-The car struggles to start (it will go with a spray of easy start) it just wont rev up.
-It will idle sweet enough, all tuned up idle- mixture running lovely. if you build the revs up until about 2.5k then it just bogs down and wont rev any more until it dies almost like the revs hit a brick wall and wont go any further.

The engine ran spot on before the carb refurb which is so annoying. trying to solve this problem its had new distributor, points, condensor, leads, plugs, coil swapped, engine gasket kit inlet rocker etc.

It has all been timed up, points checked, all good sparks present 10x + still to the same result.

As einstein said the definition of insanity is doing the same thing over and over again expecting different results.

Anyone had the same problem before? wisdom or suggestions would be extremely grateful, i just want this beast back on the road before the wife rehomes me!

Have you checked Vacuum?

1243 firing order.. yer never know lol.. :p

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Originally posted by MakeEverything
Have you checked Vacuum?

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1243 firing order.. yer never know lol.. :p

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It won't start without easy start and bogs over 2 1/2k
Sounds like your running weak past the idle and 1/3rd throttle progression
Perhaps cleaning has opened the jets or perhaps the jets have blocked with crud after cleaning has loosend
Check choke operation, throttle operation and second choke opening
I'm not sure on that carb if its a geared or vacuum secondary

thanks for reply,

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Perhaps cleaning has opened the jets or perhaps the jets have blocked with crud after cleaning has loosend Check choke operation, throttle operation and second choke opening I'm not sure on that carb if its a geared or vacuum secondary

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Have you mixed up the primary & secondary jets (both the idle and main jets)?
I did that on a 1500 pre-xflow and took me a while to figure out what I had done.

I thought the same as above, the 32 jet is for start up and idle 36 for more economical foot down driving! Good luck!

I had exactly the same problem when I bought my car. It took me weeks to get to the bottom of it, but it turned out that the gasket in the carb was upside down ( I had checked this 3 times before I noticed it ), causing it to block off a little hole. Might be worth checking if the problem only started after a carb rebuild.

thanks for the suggestions, they are both worth looking into.

i did notice the main gasket on the carb could go either way apart from a small hole at the side of the float bowl? iirc

i'll let you know the results

Right checked the jets and swapped for close to standard size, and flipped gasket over as the acc pump blank hole wasnt covered. re-checked the timing too to see if it was 180 deg out, spot on as before...

still the same behaviour.

checked the revs to see when it bogs down, and it gets too spot on 2k rpm then it dies. while it was runnging i had a look in the chamber to see what happens when it starts to die, the fuel stops squirting in the chamber? is this normal? should the fuel carry on going in as the revs increase?

still wont start cold without the easy start but starts fine when its got some temperature in the engine.

is anyone familiar with the 32/36, i'm not sure if the power valve is nackered. i've tested it (press down, cover the hole and let go) it recoils by about 3mm is this right or should it stay at full compression when you press it down? cant seem to find any info on this side of the carb.


thanks for any input/ ideas folks.

Fuel should keep squirting no matter what the revs are, one thing springs to mind is what is your fuel set up? pump? pressure regulator?

It just could be that you aren't getting enough flow or something which means that your fuel can only sustain you up until around 2000rpm and after that you are sucking the bowls dry.

If you are sure fuel is stopping then that is your issue.

thanks for your reply,

had the fuel pipe off today and cranked over (its a standard mechanical pump btw) fuel flowing nicely, the bowl are always full to the correct level, so i seems like the float is doing its job. measured the float again to check the levels 41/51mm.

it needs taking apart again to go through the jets.

If fuel is sufficiently flowing, then you may have blocked/restricted jets, or you don't have enough of the venturi effect in the carbs to suck out fuel, which could be a vacuum issue like others have stated.

Do you know the operation of the power valve? what is is supposed to do? if it might be broken like you possibly think, any way that could be shutting off your fuel when it is trying to operate?

Sounds like a really frustrating problem.

i think the basics of the powervalve and pv diaphram operations are if there is a vacuum behind the valve (accellerator operated sufficiently?) it compresses the spring on the diaphram and stops/lets the fuel through the pv (base of the float bowl).

then when there is no vacuum (at idle?) the fuel is stopped/let through by the diaphram spring pressing needle on the pv.

not sure which way around it operates? any ideas.

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Sounds like a really frustrating problem.

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looking down the carb, when you open the throttle there should be a jet of fuel pumped in from the accelerator pump. is this happening? sounds like it isn't if it won't start without an additional spray of starter fluid.
Sounds like it could be a fuel supply problem though with only enough fuel getting through to run the engine slowly, check your fliters and could there be muck in the tank blocking the outlet? Could you rig up a jury tank and feed the pump fom that?

[Edited on 11/5/13 by Dingz]

good idea about the fuel supply, the filter has been checked at the carb end but i've not checked tank end or even if it has one lol.

yea when looking down the primary chamber there is a squirt of fuel when its given some throttle, this is when running and not running.

soon as it gets to 2k rpm the jet of fuel stops coming out and it just sucks air, big sucking noise then it will die unless you let off the throttle. doenst matter if you're gentle with the revs or sharp on the gas it does the same?

We have run several FF1600s over the years and the 32/36 dgv 5 a is the only carb allowed. A brilliant piece of kit which never seems to go wrong. We remove the power valve and the complete choke assembly without any problems, we stick massive jets in and never have a problem. What jets do you have fitted, is the accelerator pump and jet clear. Have you checked the air correction jets. Have you checked the manifold to head joint is sound.....

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We remove the power valve and the complete choke assembly without any problems,

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Yes, permanently, don't need them and my engines start instantly and rev to 6800 all day. Bog standard 1600, just put together properly. You are missing something so start from scratch by stripping it and put it together again, preferably with a drawing to show which jets go where, making sure the air correctors are in the right place as well. PS, have you checked the colour of the plugs.

[Edited on 11/5/13 by redturner]

Ive been reading this thread for a while, and can only add, what i would do,

Please tell, what else was done when you took the carb off, and rebuilt it, any engine mods, or taken to bits ??

you havnt left any rag in the manifold?

Are you sure there is fuel in the carb? as you can only start the engine with easystart, and once that runs out, the engine stops

I would, in this order, take the fuel feed pipe off the fuel pump, and connect a new tube into a jerry can of new fuel
This eliminates, any fuel delivery problems

If this is still produces the same problems, I would remove the rebuilt carb, and stick another one on, and someone on here must have one lurking about in their garage!


Otherwise, you will need to film the whole process, stick it on youtube/whatever, and us the collective, can see and hear what is going on

Our xflows are so basic, that any combination of sparks and fuel will make it run, !!

ta for replies

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PS, have you checked the colour of the plugs.

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Please tell, what else was done when you took the carb off, and rebuilt it, any engine mods, or taken to bits ??

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Sounds like an internal fuel passageway has got some crud in it.

Take your air filter off and run the engine then choke off the carb with your hand until it just about stalls.
Do this a few times and the suction may dislodge the obstruction.

This has worked for me in the past.

If there is an improvement, strip the jets out and clean out the passageways again.

What is your cold starting procedure?
All engines are a bit different in their start up requirements and can depend on ambient temperatures as well.
Usually a couple of pumps of the accelerator, foot off the throttle then crank when cold will get a crossflow to fire.
May take a few repeats to get the engine to run for more than a second.

Once it fires a little choke could help.

I don't like churning them with the choke out.

[Edited on 12/5/13 by minitici]

well its finally sorted, it seemed a combination of a loose venturi and blokage was the culprit.

took it apart and blew all the jets and crevices out, and noticed the primary venturi was loose too. pucnched it back in to keep it from rattling around, reassembled and gave it a try.

started first time after a couple of twists of the gas and revved past the bog once it was warmed up

just need tuning up again now as its got a slight flat spot just as you give it sharp throttle.

i know there are plenty of tuning guides online, and i know the base settings, any tips on how to tune the weber so its just right?

Glad to hear that your got it running better.