700 double pumper on a road car

Mick · Post by **Mick** » Wed Aug 13, 14 11:05 pm

If you look on holley's website there is a dry setting for the floats, take the bowls off and set them dry, then fine adjust on the car with the motor running. That way you will be close when you fire it up, instead of fuel gushing out of the vent tubes, or cutting out because the floats are almost empty.

Dave-R · Post by **Dave-R** » Thu Aug 14, 14 8:30 am

Another thought. You have got a fuel pressure regulator between the pump and the carb haven't you? Along with a fuel pressure gauge?

Otherwise you will have variations in pressure which will effect the fuel bowl float. Holley carbs like a nice consistent 6psi min to 6.5psi max.

db · Post by db » Thu Aug 14, 14 8:47 am

Can you temporarily plumb in an elec fuel pump just to set the floats? Might be easier than trying to keep the motor running

Mick · Post by **Mick** » Thu Aug 14, 14 9:31 am

db wrote:Can you temporarily plumb in an elec fuel pump just to set the floats? Might be easier than trying to keep the motor running

So not only has he got to try and set his carb up, he's now required to go an purchase an electric fuel pump, just to prevent running his motor for 10 mins.

GJUK · Post by **GJUK** » Thu Aug 14, 14 9:41 am

Dave wrote:Another thought. You have got a fuel pressure regulator between the pump and the carb haven't you? Along with a fuel pressure gauge?

Otherwise you will have variations in pressure which will effect the fuel bowl float. Holley carbs like a nice consistent 6psi min to 6.5psi max.

I saw this on another forum, no I have not and im starting to think that might be an issue.

Jon

GJUK · Post by **GJUK** » Thu Aug 14, 14 10:00 am

db wrote:Can you temporarily plumb in an elec fuel pump just to set the floats? Might be easier than trying to keep the motor running

I understand where you are coming from, I read that with an electric pump you do not need to run the engine. I'm not going down that route but I can see why its much better. Cheers

GJUK · Post by **GJUK** » Thu Aug 14, 14 10:01 am

Mick wrote:If you look on holley's website there is a dry setting for the floats, take the bowls off and set them dry, then fine adjust on the car with the motor running. That way you will be close when you fire it up, instead of fuel gushing out of the vent tubes, or cutting out because the floats are almost empty.

I'll have a look.

I've just bought a holley fuel pressure regulator and fittings. Hope they arrive tomorrow.

Jon

GJUK · Post by **GJUK** » Thu Aug 14, 14 11:53 am

Torques on eBay service is top notch by the way. All the bits should be here tomorrow.

\o/

Mick · Post by **Mick** » Thu Aug 14, 14 12:35 pm

Yeah i used them when i updated my fuel system.

Mick · Post by **Mick** » Thu Aug 14, 14 12:47 pm

Here you go Jon

http://www.google.co.uk/url?sa=t&rct=j& ... WU&cad=rja

db · Post by db » Thu Aug 14, 14 5:04 pm

GJUK wrote:Torques on eBay service is top notch by the way. All the bits should be here tomorrow.

\o/

Yeah, I've had lots of stuff from them. Great service and great kit

My fuel pump is electric and apart from the issue of not having to keep the motor running, I don't get smoked out of the garage

GJUK · Post by **GJUK** » Fri Aug 15, 14 3:15 pm

So my Holley Fuel regulator just showed up and on page one of the manual it states "this must not be used with a mechanical fuel pump"

Whaaaaaaaaattttt!

GJUK · Post by **GJUK** » Fri Aug 15, 14 3:18 pm

oh no, its okay it was quoting another model phew.

GJUK · Post by **GJUK** » Sun Aug 17, 14 8:30 pm

Big update!

(Long update here, still have a problem)

So, spent the whole weekend on the car.

Saturday

Got the carb running okay with a friend, kind of got the timing there abouts though when you put the car in to D or under any load its just stopped.

Stripped the dizzy, seems it has very light springs in it - the kit I bought from Turnip on here will not fit the dizzy (my one has a screw adjuster in it already for limiting the timing total advance). The lightest spring in the kit was much heavier than the springs on the dizzy (so I assume the timing kicks in very quickly).

Sunday.

Mick kindly popped over.

Got the car running even better.
Idles at 1050 rpm, seems happy there, does not like going any lower.
15 16 inches of vac on idle
in drive its 800rpm and holds well

Test driver 1 and 2:

Took the car out, idles well, pulls much better than ever before. 1-2 flat out to 5k rpm really great. Did another full run into third. Pulls really well then off the throttle the car chokes up, doesnt like it and dies.

You can't start the car at all, unless you have the throttle wide open?! Then it runs like a bag of ****, nurse it home. On the drive its idling and running fine again ?!?!?! It only seems to run like a pig after giving it beans.

changed parts

known working coil changed
rotor arm changed
New HT leads
New king lead from coil to dizzy
New carb gaskets fitted
Carb fully rebuilt by someone that knows what they are doing

checks
Plugs all cleaned and checked firing all okay. All 8 checked all 8 HT leads checked
plugs are now a nice brown
Fuel pressure is 6.7 psi
no fuel leaks
no air leaks
no Vac in use
Vac pipes blocked off

carb checks:
fuel bowls correct, primary and secondary
jet size okay (stock for 700 dp)
blade openings okay

Further ideas I've been given

ballast check for cracks (top of the engine bay)?
drilling the throttle blades?
change the ignition module?
fuel boiling?

Timing was an issue and mostly done by ear as TDC was impossible to find on the markings on the damper, I am going to have to find TDC and check the timing. That said the car runs a DREAM now, apart from when you come off the gas after booting it through the gears and just decides to go in to special mode and stops.

So, any more ideas guys?

From what I call tell the timing is spot on. The carb is spot on. The car is happy, something else is causing this problem is my gut feeling... I've had bulk head connector issues before now... Not sure.

J

Mick · Post by **Mick** » Sun Aug 17, 14 10:49 pm

Just to add, initially when we took it out it would tick over fine and run through the gears without a problem but after going two or three miles we turned round to come back, Jon floored it down this carriageway then when we came to slow down for the lights it started running rough and then stalled at the lights. We gave a minute to cool, Jon had to pump it a couple of times to get it started. Then we drove the rest of the way where it started missing and trying to stall at the lights. When we pulled onto Jon's road i told him to floor it and it seemed to clear and then rev fairly ok. The timing light showed it massively over advanced but it ran cool, ticked over and revved clean with no detonation or pulling on the starter, which makes me think the tdc mark is wrong. I checked and adjusted the float heights a little and they are fine, also set the vac at it's highest but did have to turn the idle screw in a little. Before i advanced the timing it wouldn't tick over, stalled in gear and the plugs were sooted black.
Mick