Carb Spitting

[jamesdennison]

2000 engine with strombergs.

 

When the engine is cold and I'm on choke I get spits out of the carbs.  Particularly when pulling away.   Goes away after 5 miles or so when warmed up.

 

Normal?

 

(bit embarrassing the other night when pulling out of a classic car meet past the crowd of onlookers!)

 

 

[Pete Lewis]

Do you use engine oil in the dsahpots?

 

check ingition timing tomfactory spec and use 97+ron fuel so ign is not retarded to suit 95ron,

 

check tappets are 0.010" cold

 

keep, an eye on the diaphragms , if they get wrinkled with oil wash in petrol to revert them back to shape

pete

[jamesdennison]

Yep - 20/50 engine oil in dashpots

 

Timing is 10 deg BDTC so slightly retarded from factory (8 BTDC) so I can adjust that and run with higher octane to see if it helps.

 

Just done tappets .... I'll have a look at diaphragms.

[Pete Lewis]

10 deg with a spec of 8deg is advanced by 2deg not retarded

 

put that right first, if you are wanting to retard to use 95 fuel you need 6 not 10

they were never designed to run on 2star fuel

 

should realy stick with ultimate type 99 fuels and use the factory settings for best performance

[jamesdennison]

Just to follow up

 

I set timing to 8 degrees and ran for a 100 miles or so.  Car was really struggling, no power whatsoever and getting very hot so I'm back to 10 degrees!

 

Looking in the book 8 degrees is the figure for static timing and I'm using a strobe with the engine running.  t'internet seems to suggest that it is common practice to add a couple of degrees on to static timing when using strobe.

 

Still getting the odd spit.  I've had the diaphragms out and look ok, but will will order a couple more next time I buy some other bits (I know about lining up the lugs etc to get these to fit right).

 

To be honest it is a problem I can live with as it is only when running cold.

 

What did surprise me was the massive difference in power those 2 degrees made to the timing.  The car doesn't pink at 10 degrees so I am quite tempted to advance a little more until it does pink and then retard back to see where I end up.... perhaps there are a few more horses lurking under the hood 

[Pete Lewis]

Its not unkown formthe timing rim to loose ot bonding and move round the pulley

this is really a harmonic damper for crank vibrations and is conveinient to put the timming marks butnif the rubber bond gives up the outer rim can actually move

 

time it by advance till it pinks and then drop it back a little

 

or give it a 1200 idle and turn the dizzy to get fastest running, then back it off to be just less than best

 

or add a vacuum gauge and advance to give 18 to 21 inhg at idle

 

pete