Interesting Hot Start observation

[wolfman]

Ok this is interesting.  She has NEVER run better or smoother.  The stumble is GONE 99.9% of the time at any RPM range.  I have been running a 1/2 bottle of Techron gas additive with the last two tanks of gas.  She even runs decent, maybe even better, on 87 Octane regular now..BUT..on CLOSED throtle (no choke) hot starts she kicks back.  Always starts within 4~5 seconds (or LESS)  of cranking but always CLACKS! at least once in the process.  BUT, if I goose the throttle SLIGHTLY (about 1/8 of a full turn) and return it to fully closed FIRST, and THEN hit the starter, she'll crank for about 1 extra second and start right up with NO kick back or CLACK! at all? If I shut her down and restart immediately, she fires right up in a second or two with no clack.. This suggests to me that the idle mixture screws are still off (sigh...back to the drawing board) what do you guys think?  Of note:  The idle speed has gone up to 1500 from my setting of 1300 rpm all by itself since the two Techron treated tanks have been consumed...

[Lucky]

The kickback/clack is indicative of either a weak charging system, problems with the starter clutch, or both.  
--Lucky

[wolfman]

Not to doubt you but...Starter clutch fix, new stator and R/R all done in the last 5 months.  Battery is fully charged, Charging system output is 13.8~14.4 volts consistantly depending on load and RPM when running, and the starter (with less than 8k miles on it) is dry.  If it were the starter, why would giving it that tiny shot of fuel pre-crank prevent the kickback?

[Lucky]

kick-back is caused by the cranking system not having quite enough 'oomph' to move the crank fast enough to overcome compression. at that critical moment the starter clutch rollers lip & you get kick-back.

if your sure it's not the things mentioned, look for other problems along that line of thinking.  new oil that's too heavy, high resistance in the starter circut, worn push button switch.

something is preventing it from having the oomph needed the first time, the extra shot of fuel is giving it the fire needed though.....

[Walt_M.]

I would tend to agree with Lucky on this one, think it's your battery going away. As for the fuel additive, if your carbs are clean and it is running good, why use a cleaner? May be worthwhile to do it every 2-3 thousand but every tank is a waste of money.

[Lucky]

Walt, I think Wolfie means he used the additive just to run thru the tank twice, same as i'd use the Berrymans injector cleaner twice in a row at the start of a season.  he's just now getting his carbs into shape.

[wolfman]

Well...It was not the battery or starter.  I logic'd it out.  I never got the CLACK or kick back when starting COLD (thick oil, weaker battery from sitting) only when HOT (thin oil fully charged battery) .  When HOT I did NOT use the choke, which bypasses the normal idle circuit, and DID get the CLACK unless I gave a tiny throttle twist (and resulting fuel squirt from the accelerator pump) FIRST.  Soooo...I readjusted the idle mixture screws slightly richer and TA DA!  No more clack on hot start up.

[Lead_Deficiency]

Can you add a link to a sound file of the engine noise, might be a lot easier to diagnose.