Smoke from near air filters!!

[RogNeedham]

Accelerating away from a junction and holding car in third at c.3k rpm ready ot overtake truck my car ('91 Xflow on twin DCOE 45s), wnet sluggish, chuffed a bit, then smoke appeared from the bonnet by the filters. Engine also revved up to 3000 once I depressed the clutch.

 

I managed to coast into a layby and kill the engine. Smoke disipated quickly enough. After a couple of phone calls I waited for c. 5-10 minutes and tried the car again. After a little persuasion it fired up and I completed the remainder of my journey (c.4 miles).

 

I kept it to

 

Rog

[westy]

Are you sure it didn't just spit back through the carbs, mine does that quite a bit this weather.

 

[rgrigsby]

Same here both the xflows I've had have done this to one extent or another, my current one with 45's and a 264 cam does it regularly especially when you back off after accelerating. As long as it's not HUGE clouds of smoke I wouldn't be worried.

 

Rob G

www.SpeedySeven.com

[Terry Field]

Rog, I had the same problem a couple times on my XFlow on 40's - lots of white smoke. The secret is to switch off quick and then start it up after a few minutes. I understand that it is unburnt petrol spitting back and catching fire in the air filters. K&N's deal with this well if you switch off fairly quickly, otherwise you might melt the rubber surrounds.

 

I spoke to Caterham about this, and their only recommendation was to try to run a bit leaner,but it hasn't been a problem as long as you are aware it can happen.

 

Terry

 

Trying to get out of the garage

[Peter Carmichael]

The "smoke" is unignited fuel vapour and is highly flammable. This is why it is advisable to have a fire extinguisher to hand, especially in a carbed Seven.

[RogNeedham]

Thanks to all for your advice - got home no problems after a pleasant blat through the Derbyshire/Staffs lanes 😬 😬 😬 *thumbup* *cool*

 

Cheers

 

Rog

[Hilbron Runde]

Hei, just a question to this thread, I had a similar problem some while back had driven my x/ flow on 40's for a long run with no problems had to take a ferry over a fjord, car started ok but died about 100m after driving up the road, realy embarassing with a lot of cars behind you. Anyway the car did start eventually and had no further problems. The engine spits and pops when cold but when it's up to running temp everything is fine, I am just wondering if the grade of petrol could be a problem, I am still using leaded but the quality is not the same from the different petrol suppliers, I found Shell to be the worst, any comments ?

[tiddy1]

My old crossflow set the KNs on fire a few times, quite alarming really,

 

You may find that it is fuel comming out of the overflow from the float chamber and spilling back into the filter. I found that there were some burrs on the float where the two halves were joined together, this caught on the side of the float chamber and jammed the float up so the needle valve would not shut, hence fuel pissing out into the filter

 

Sounds like yours is just spitting back but if you actually have fuel leaking out it is worth checking the floats

 

Simon