question on timing

[fsmyth]

I have noticed that when a tank gets empty (right before I switch) the engine smooths out and gains speed.
Is this a timing issue? There is no excessive smoke - what there is white/light gray. No black.
Cold - rattles a bit (high idle and cold advance). When it warms up, the idle drops and it gets quieter.
Runs cool - EGT at idle ~250, but I can easily get it to 1150 with a decent load and lots of pedal.
Is my timing retarded?
<als>

 

[Kistthesky]

I have noticed that when a tank gets empty (right before I switch) the engine smooths out and gains speed.
Is this a timing issue? There is no excessive smoke - what there is white/light gray. No black.

I

The same thing happens right before you run out of fuel then it dies, or if you have serious air intrusion, or your IP is on the way out. In other words don't worry about it, it's just an air bubble, just switch tanks before they run dry, better that way anyway to avoid sucking up any scrap from the tank.

 

[OLDBULL8]

It's not a timing problem. Your fuel gauge could be off a little and your sucking air, the so called shower head in the tank could have fallen off or deteriorated, that happens with a 1/4 tank or less. Speed up is a results of the right mixture of air and fuel, air bubbles in the fuel.

 

[icanfixall]

What you described is running out of fuel. The advance increases causing what you feel. Now the bad part of this. If it happens around 1/4 tank then that tank has a suction head thats broken off. Then the last 1/4 tank of fuel can't be suckked up. Now the really bad part. About 80+% of the fuel pushed thru the injection pump and injectors is only for cooling and lube. The injection pump is expensive and has tolerances less than 0.0005. Thats half a thousands. So how long are you running that with little or no lube or cooling and what damage are you ending up doing. I understand we all want to "get that last drop of fuel" out of the tanks. But please don't. you not doing that much harm but why do any harm...