carbs hot cold start

herpmad · Post by **herpmad** » Sat Nov 15, 2008 6:32 pm

ok before i strip them down and clean the carbs i had topcat round to day to give me a clue about my engine (big thanks m8) ok we no the carbs are running a bit lean on cold start up but once the engine is hot it still struggles to kick in once its running its fine its just when starting it seem to not wont to fire up so im going to adjust them to make them a bit more rich (any advise) but just wont to see if anyone can point me to a thread to why its struggling to kick in or is it time to strip them down give them a make over and take it from there if i do strip them down is there any think i should be replacing or keeping a close out for ??

cheers
shane

Ian Anderson · Post by **Ian Anderson** » Sat Nov 15, 2008 7:59 pm

What is the engine? Ford/ Chev/ Rover/ Other
What are the carbs? Holley / Weber / SU/ Solex
Any mods on the motor?

Is timing known to be OK?

Ian

herpmad · Post by **herpmad** » Sat Nov 15, 2008 10:16 pm

sorry engine is a 3.5 rover v8 carbs are Solex no mods and timing sounds ok although it on my list of things to get checked

RoverP6B · Post by **RoverP6B** » Sat Nov 15, 2008 11:18 pm

Before you touch the carbs, you must ensure that the ignition timing is correct along with the idle speed. Otherwise if you adjust the carbs, then the timing, the carb settings will then be wrong most likely, and you will have to do them again.

Ron.

CastleMGBV8 · Post by **CastleMGBV8** » Sun Nov 16, 2008 1:13 am

Worth checking the diaphrams in the carbs, they commonly fail.

Kevin.

topcatcustom · Post by **topcatcustom** » Sun Nov 16, 2008 8:08 am

Once it was started it idled nice with a little bit of choke, the carbs could be 30years old so I thought there may be a good chance they could do with some new rubber bits and gaskets inside even if they are not completely to blame for the starting problem! Yet to strobe the timing tho...

kiwicar · Post by **kiwicar** » Sun Nov 16, 2008 8:32 am

Ah solex
If it is not the diaphrams (at thirty years old these should be good and perished by now) worth changing if they havent been done in the last 10 years as they not only split they get little pin holes in them.
Then the other thing with solexes is the idle and part throttle transition is done by lots of little drillings in the body of the carb, if it has been stood for any time full of leaded fuel (actually even unleaded but not as quickly)you get all these bunged up with gunge, this design was asmuch to get around patents on the SU as let the car idle, a solex carb will idle on the main ventury, but not as well as if it is all clean. Oh if it has an auto choke get rid of it (though it sounds like you havent).
Mike

herpmad · Post by **herpmad** » Sun Nov 16, 2008 9:59 am

ok new carb refreb kit on its way so i need to get the timing checked before i take them off ?? or should i be ok to take off refreb and put back on

and its a manual chock just needs slight adjusting

herpmad · Post by **herpmad** » Sun Nov 16, 2008 11:16 am

ok blond moment coming are solex the same or very simalar to to kenith stromberg cause the carbs are solex but the discription in the manual discribs them as kenith stromberg the pictures are of the same cabs (through my untrained eyes lol)

kiwicar · Post by **kiwicar** » Sun Nov 16, 2008 1:19 pm

sorry, stromberg carbs, solex make them.
Mike

herpmad · Post by **herpmad** » Sun Nov 16, 2008 3:13 pm

cheers m8 that makes it easyer finding the service kit

topcatcustom · Post by **topcatcustom** » Sun Nov 16, 2008 6:09 pm

How about swapping the Solex's for Su's? Anything to be gained? (as they are plentiful & pretty cheap!)

herpmad · Post by **herpmad** » Sun Nov 16, 2008 11:43 pm

are su easyer to work with from looking around it appears they are easer to adjust

Quagmire · Post by **Quagmire** » Mon Nov 17, 2008 8:06 am

I have no experience of Strombergs, but i did recently strip down, clean and reassemble my SU's with all new seals.

All i can say is that it was amazingly simple! My carb experience until then had only been the smaller Weber and Zenith carbs used on the 2.25 LR lumps and they were complicated in comparison.

The plus with the SU's is that there is no rubber diaphragm to perish...

kiwicar · Post by **kiwicar** » Mon Nov 17, 2008 4:27 pm

SU's, basic design from about 1905 ish, not really changed from then (apart from moving the float bowl). the newest ones are from the mid 80's so are pretty old, the pistons wear where they fit the venturi with the result that they become very difficult to set up especially at idle and the transition to part throttle. lots of needles, jets and springs available and if unworn in basic form (no fancy doo dads for emisions) are straightforward to set up and stable once done.
Solex/ stromberg, about 25 years old (newest ones) don't have the piston wear problem to the same extent as the SU as the diaphram forms a full seal to the top of the carb. This diaphram (and the cheeper build quality) are its big reliability problem. The Stromberg is really an attempt to build a variable venturi carb without paying royalties to SU as a result things like the transition CCT and the Idle and choke set ups are to work around the simple copyrighted bits of the SU. Basically not a bad carb, but limmited needles and springs, can't use SUbits as they do not fit properly and all the daft drillings get bunged up.
If you can find someone doing new pistons and bells and venturi sleeves for the SU (and people do them fron time to time) then that is your best bet. No one bothers with the stromberg so actually they can be found in virtually new condition (swapped for SUs when virtually new) for peanuts but you need to find good ones.
Mike