My guess would be brief fuel starvation - possible some sediment is briefly
blocking the port at the bottom of the float bowl or the bottom of the jet
(I am assuming HS4 carbs from the description in the message).
If you had vapor lock, it could cause similar symptoms but usually only
under hot conditions/warm engine. It wouldn't happen on a cold engine.
Its possible that the float could stick, not allowing the fuel into the
float bowl briefly. However I have never seen this in a SU carb. My
Landcruiser has had this problem but only on a cold engine with outside
temps well below zero.
In short, if I had a problem like you described, I would disassemble and
clean out the carbs. Particularly in the float bowl area. And install
and/or replace a fuel filter in your line.
David
67 BGT
71 BGT
At 11:55 PM 5/27/00 -0400, Geoffrey Gallaway wrote:
>This problem has been plaguing me for a week now, I've tried everything I
>can think of.. I replaced the fuel pump, fitler, hoses, carbs and
>tightened everthing down.
>
>When the engine is cold/hasnt been drivin in hours:
>Accelerating from a stop somewhat powerfully through all gears the engine
>will "stutter" around 3rd gear at 3000 rpms. This is almost 100% reliable
>and perfect. Get on the highway and every once and a while it will stutter
>or choke. If you floor the gas while its stuttering, it picks up power
>while stuttering for a second then goes back to regular/clean
>acceleration. If you don't do anything while its stuttering, it just
>clears up in a second.
>
>If the engine is hot/just drivin:
>Starting from a stop somewhat powerfully (as above) causes the engine go
>give out/die at around the same spot as when cold. If you floor the gas,
>it sputters badly, dies, sputters back again and starts running correctly.
>On the highway, the same thing occurs once and a while. At times, the
>problem gets so bad, the car just dies requiring a very lengthly restart
>(usually ticking off the people behind me)..
>
>This problem gets worse and worse every time the engine dies and needs a
>restart. If I take the gas line off the first carb, put it into a can and
>turn the fuel pump on, gas seems to come out fast, powerfully and
>reliably.
>
>It may be that the spot where the engine is dying (when starting off from
>a stop) is the same spot where the gas bowls on the carbs run out of fuel.
>If I understand the system correctly, the fuel pump will pump as much fuel
>into the system until the bowls are full of fuel and then slow down/stop.
>
>Questions:
>* If there is air in the gas line somewhere, how will this affect the
>engine?
>* Each carb has its own fuel bowl with one daisy chained to the other.
>This means that the first bowl has to fill up before the gas flows over
>into the second bowl. Could this be affecting something?
>* What is vapor lock and could this be affecting anything?
>* Why won't it stay running?
>* Does anyone want to take me to a local pub and pay for a few beers and
>then drive me home?
>
>Geoff
>
>--
>Geoffrey Gallaway || I dunno, I dream in Perl sometimes.
>geoffeg@sloth.org ||
>D e v o r z h u n || -- Larry Wall
|