Flat spots

[OLIVE-BAY]

Morning, having a problem with our 68 bay running a 1600 twin port with 009 dizzy, on pulling sway I have a huge flat spot that I just can't cure. I've replaced the points and condenser, the ht leads, coil, plugs, and dizzy are recent replacements. I've tried turning the body of dizzy to fine tune the timing but then I end up with a really slow turn over when trying to start the van. The battery is brand new and starter motor was replaced last summer.
I have also checked that the rubber hose from the air cleaner to the top of the carb is not cracked and is sealed.
Any suggestions?
Cheers
Oli

 

[Paul Weeding]

Take the 009 off and fit a svda distributor...

Timing should also be set with a strobe gun.. Random turning of the dizzy is a very bad idea

 

[Trikky2]

First set your timing to 7.5 degrees BTDC static. You can check total advance at 3000 rpm with a timing gun later.

Try adjusting the small tickover mixture screw on the carb. With the engine warm turn it gently clockwise. As soon as the engine slows turn it back out slowly until the engine slows again. Then turn it clockwise again just until the engine idles at its smoothest and fastest tickover.

If the idle speed is now too high, slow it down with the idle speed screw (Not the mixture screw).

If you have had to adjust the idle speed then repeat the mixture setting procedure to double check its still at its optimum setting.

If this doesn't fix your problem then come back on here for some further things to check.

Edit ps. Paul is quite right, random twiddling with the dissy timing is a shortcut to overheating and a wrecked engine.

 

[OLIVE-BAY]

Ok cool I'll go and do that now and report back.

 

[madmike]

Let me Guess,a pict34 carb? don't work to well with a 009
find a 034 vac.dizzy
don't time 009's @ IDLE!!!!!!!!!!!!!!!!!
get a timing light rev to 3000 and set @28*-32*
all motors are different some like 28* or 30* set and test drive
then whatever it is @ Idle so be it,,

 

[jonboylaw]

As above, set max advance at 3000 rpm, the idle will be what it is ( unless you have a programmable system)


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[OLIVE-BAY]

To be fair I've never had any running issues until recently, so the 28-32 is after tdc? It's too to cold to go out recently but today looks better so I'll get out there!!

 

[Resto-raider]

I never had any problems with a 34Pict3 carb and a genuine 009 Bosch distributor. It should run fine if set up correctly.
Have you looked at the jets in the carb? Are they the right size and are they still clean? Does the accelerator pump in the carb still work correctly?

 

[jonboylaw]

Err no, the advance is BTDC, in advance on the piston getting to the top of the bore on the ignition stroke. It is to allow the flame front to be maximal as the piston reaches the top this max power.

ATDC is retarding, firing on the down stroke when the cylinder is decompressing. Your engine will not make any power if indeed it runs at all.

Just a thought but is the accelerator pump working? If you open the throttle you should see a heathy squirt of fuel from the accelerator pump into the top of the carb.


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[OLIVE-BAY]

Cheers all...all running fine again now.
Thanks again

Oli