700 double pumper on a road car

Blue · Post by **Blue** » Sun Aug 10, 14 10:32 am

Yes way over jetted, my Valiant was the same when I checked it. I think half the time the Americans just grab whatever they have to hand and use that right or wrong...

Pete · Post by **Pete** » Sun Aug 10, 14 10:33 am

We only run 93 square in a 512 ci Max Wedge headed race car..........you jet for your specific application....

GJUK · Post by **GJUK** » Sun Aug 10, 14 10:33 am

Thank you, it's a start at least.

We'll get there!

GJUK · Post by **GJUK** » Sun Aug 10, 14 10:36 am

Pete wrote:We only run 93 square in a 512 ci Max Wedge headed race car..........you jet for your specific application....

Maybe he used some 99 jets he took off the NASA's space shuttle?

Bozwell · Post by **Bozwell** » Sun Aug 10, 14 10:40 am

are you sure they are not 66 jets you're reading upside down

GJUK · Post by **GJUK** » Sun Aug 10, 14 11:50 am

Bozwell wrote:are you sure they are not 66 jets you're reading upside down

Oops I think you are right

MilesnMiles · Post by **MilesnMiles** » Sun Aug 10, 14 12:07 pm

Back to the drawing board!! Set the float level correctly and then see how it is.
Have you changed the power valve or is it blown? If so, a incorrectly positioned gasket, or blown power valve will allow the flooding you refer to. Made that mistake myself a little while ago.

GJUK · Post by **GJUK** » Sun Aug 10, 14 1:35 pm

MilesnMiles wrote:Back to the drawing board!! Set the float level correctly and then see how it is.
Have you changed the power valve or is it blown? If so, a incorrectly positioned gasket, or blown power valve will allow the flooding you refer to. Made that mistake myself a little while ago.

Will just my friend to rebuild it will me and go from there *sigh*. He mentioned the power valve also, which it does have.

Thanks

Jon

Mick · Post by **Mick** » Sun Aug 10, 14 2:04 pm

Get everything back to stock set the float height check the throttle blades are set right, there's a small screw underneath to adjust the transfer slot it needs to be a square not oblong, turn your mixture screws 1.5 turns out and try it, if it runs ok, stick a vac gauge on it and adjust the mixture for max vac. Your reading will give you an idea on pv size. I start with half the vac + 2 and work from there.
Mick

GJUK · Post by **GJUK** » Sun Aug 10, 14 2:09 pm

GJUK · Post by **GJUK** » Mon Aug 11, 14 11:12 pm

Update:

My friend very kindly spent the evening rebuilding the carb with me, explaining what everything does.

Found the throttle blades were open way past where they should be.
One of the floats though it was sealed was not closing the valve that lets fuel in
Some screws that held everything together were not as tight as they should have been
... There were loads more bits wrong with it, though its all back now at 'base level'. It was very interesting to get involved in it.

Will bolt it all up on Wednesday and see how it runs.

Dave-R · Post by **Dave-R** » Tue Aug 12, 14 8:48 am

If the engine has a big cam the throttle was probably opened up way too much just to get it to run.

Big cams need lots of initial timing to get the idle speed high enough with the throttle closed and sometimes some small air holes drilled in the throttle blades too.

autofetish · Post by **autofetish** » Tue Aug 12, 14 9:31 am

Really interesting keep us posted on how you get on

Pictures !!!!!

db · Post by db » Tue Aug 12, 14 11:44 am

Something to remember when jetting- Holley jet sizes don't refer to the actual hole size, it's just a numerical reference number, eg a 99 Holley jet is 0.125"
If you have MaxJet jet's, they're referred to by actual drilling size, Luckily they're easy to spot!

GJUK · Post by **GJUK** » Tue Aug 12, 14 7:56 pm

Thanks.

Here is the carb, ready to go in:

How would everyone route their fuel hoses (I've replaced these also).

Up and over the dizzy, or around (kind of tight) and under.

Thanks,

Jon