Popping and Flames


04/06/2001 07:57 PM

My engine is popping and throwing flames out the carbs. Idle is fine, but as
you crack the throttle the engine loses power and starts to pop out of both
carbs. I checked the float level many times and I THINK it is correct,
about 18 mm. Timing and dewell have also been checked. The fuel in the
venturi's looks as if its being pushed around in different directions
instead of sucked down. I dont think its mech because it doesnt do this at
2000 rpms. Electrical?? Does this sound like a coil??? thanks


08/07/2001 04:33 AM

Dear Bud,
Check to see if the carbs are injecting from the acclerator nozzles. If
you look down the carb bore when you move the throttle linkage from idle to
full you should see some raw gas being squirted from these nozzles, if not
the engine will hesitate and stumble. You did not say what kind of motor you
have but if the carbs are Zenith its .25-.35 cc per 2 full strokes and a
Solex P11 is .55-.65 per Two strokes. The eyeball calibration is look down
the carb bores and they should squirt for a couple of seconds on a one full
The Stable, San Francisco


04/07/2001 07:51 AM

Bud wrote:

Dear Bud:

There are many possible causes of this. The first thing to do is be
sure the basics are right.
After Absolutely determining TDC on #1 Cylinder, DOUBLE Check the
Firing Order 1-4-3-2 in Clockwise Order on the Distributor cap. Swapped
plug wires is the #1 Reason for Bad Backfires on both carbs.
Pull the Plugs and replace them if they're wet or black. Check for
dinged-over tips on extended tip plugs.
Check the Valve Gap (0 or negative gap on the Intake Valves can cause
bad backfiring). While there, check for a broken valve spring or a seized
valve that has a 1/4" gap on the push rod.

Report what you find and:
Keep the 356 Faith


04/07/2001 01:55 PM

What do you do for dinged over tips on spark plugs? I am using W6B (?) Bosch
and noticed that I get one of my tips dinged over. I have a rebuilt normal
with Shasta pistons and barrels and normal heads that have been "cut" for the
Shasta pistons.
Pat Daily


04/07/2001 02:28 PM


04/07/2001 02:39 PM


04/07/2001 04:02 PM

Here are the things that I also did
Checked wires for firing order many times
Adjusted the valves
No dings on plugs
Rebuilt fuel pump and check quantity of output
Cleaned carb,,,jets ,,emulsion tubes etc
Checked timing and the advance,,about 5BTDC at idle and about 31@ 3500

----- Original Message -----
From: "Harry Pellow"
To: <356talk@356registry.org>
Sent: Saturday, April 07, 2001 3:51 AM
Subject: re: Popping and Flames

> Bud wrote: