unhappy b14 - now with less black smoke

Post by **Vart** » 25 Aug 2008 10:42 pm

evening,

went to make my merry way back from suffolk to portsmouth earlier to discover my 340 isn't prepared to do this. started ok if a little spluttery but choke on and away i went. first hill to coast down - died - into 3rd clutch up and away it went again did this a few more times and i turned around and went back. the idle now was almost working running at around ~400rpm this didn't improve when i jabbed the go pedal and let it settle. a restart later and it was fine - perfect even so i took it for a run round the block and it was completely normal parked up off/on and back to its bad self.

the exhaust - badly fitted by a large national retailer (backbox cut/shut into a middle box (i had to be back in portsmouth that afternoon)) leaks appallingly from the rear pipe join but for this to very suddenly affect the idle???

i also noted the in-line fuel filter was completely full at tick over - usually this is only full enough for petrol to flow between either end.

am i to understand that the engine is sucking in air from the hole in the exhaust and not much from the carb giving running problems and the fuel filter scenario? - the car runs fine on choke (rich + too much air = ok??) and will drive if a little sluggishly.

any thoughts?

back to hondaing in to work for another week....

cheers

toby

Post by **bogbasic** » 27 Aug 2008 03:57 pm

Hello, sounds like the idle solenoid in the carb. They work intermittently causing sporadic cutting out at low revs. Might also be the restriction in the air pipe that goes from rocker cover to base of carb. It can become blocked and cause similar problems. Might be worth testing these two things and if still a problem maybe the carb gaskets? I've had all of these problems! ttfn, bogbasic.

Post by **Vart** » 27 Aug 2008 06:33 pm

could be the idle solenoid - its gone before or gummed up but it wasn't this bad i'll see about a swap. hmmm. doubt its the gaskets - there quite new and haven't been touched for a while.

cheers

toby

Post by **Vart** » 31 Aug 2008 05:06 pm

700 mile trip in last few days:

my b14 has started to:

Smoke - black when coming off load accompanied by soft popping from exhaust

idle - none. won't idle with the airbox on - needs the mixture screw in tight when the airbox/filter goes on.

be a pig when cold.

now, its overdue a dizzy cap and rotor arm and leads and air filter but this is a very sudden change - certainly the mixture with the filter on is ultra lean to get it to idle smoothly leading me to think blocked filter but this is too sudden. likewise the black smoke and poor low speed running makes makes me think the ignition bits are broken.

any thoughts?

oh anyone have an idle solenoid for sale or know a supplier?

cheers

toby

Website · Post by **antiekeradio** » 31 Aug 2008 08:29 pm

float valve stuck open or float leaking.

assuming, ofcourse, that you checked the tightness of the 5 bolts holding the carburettor halves together..

Post by **Vart** » 31 Aug 2008 09:11 pm

hmm hadn't thought about that.

the fuel economy is pretty good still tho - would this change the diagnosis?

cheers - i'll have a look tomorrow.

Post by **Vart** » 04 Sep 2008 07:57 pm

Carb Stripped and cleaned and put back together with a rebuild kit from fast roadcars - put back together without any spare parts.

anyone have any advice on initial setup of idle and mixture? i seem to recall both should start off at 1.5 turns from tight then once warm adjust idle down then sort mixture (turn until idle highest) then re adjust idle. however does this initial setup prompt actual starting?

any thoughts?

Website · Post by **antiekeradio** » 05 Sep 2008 12:01 am

you should re-adjust idle a bit sooner; if the mixture screw influences it considerably.

Post by **Vart** » 06 Sep 2008 04:39 pm

replaced the rebuilt carb earlier and now all is well - You were right Wouter the idle needed almost instant backing off then it was a gradual adjustment of mixture and idle to settle it at about 900 - sits there fine now. sooty black smoke now gone and drives smoother.

thanks all for advice

cheers

toby

Post by **pettaw** » 07 Sep 2008 04:35 pm

Toby did you set the mixture for highest idle? If so you'll be too rich, you need to set mixture for highest idle, then readjust idle to approx 950rpm. Then you screw the mixture screw in to weaken the mixture carefully until the revs settle at 900rpm. That will give approx the correct mixture.

Post by **Vart** » 07 Sep 2008 09:17 pm

i set and reset it a several times - each highest idle then back the idle off to around 900 (i prefer it a little higher than the (+/- 50) 800) then check the mixture again, moving it to find the new highest point then re-checking the idle. took a while and after a long run to check it it ended up at just under 1k. i'll reset this next time it stops raining (if...)

cheers for info tho

thanks

toby

Post by **Vart** » 08 Sep 2008 05:18 pm

*update*

the igniton system is new other than renix. so for now i'm ruling that out for now.

*Edit*

the idle is all over the shop now.

starting - started on full choke and fires up to 2000 rpm then collapses and splutters - doesn't really matter where the choke is after this - bounces about 1k rpm. can be held on the throttle ok.

- after a minute or so the engine will run without choke ok but tends to idle high (around 1200rpm)

- the engine heats up quickly and after a few miles in mixed traffic idles around 900.

throughout all this its very lumpy and will just stall without prompting if i don't pay careful attention.

runs fine off idle...

this seems to point to rich running but the mixture can only go in so far until it stalls - presumably through lack of fuel... any chance the idle solenoid is playing up. there is a click when i turn the ignition but i couldn't get any life out of it using a 12v adapter (less than 1A however).

also see: my blue peter appeal for a spare/loan

thoughts?

Post by **Vart** » 14 Sep 2008 07:27 pm

after yet more trauma with this carb - i replaced the idle solenoid to no avail - i conclude the bolt nearest the fuel inlet is the problem.

this bolt is threaded but given there are 4 others i figured this shouldn't be the problem. its proximity to the idle channel (or at least the passage where the fuel escapes to the mixture screw) leads me to think too much fuel is getting in or is filling the float bowl. fuel economy is now sub 25mpg...

i can smell fuel when the heater fan is on so i think i'm going to not drive it for a while until i get a replacement carb. how hard / possible is re-tapping a thread in the carb? the metal doesn't look particularly thick....

Post by **Vart** » 25 Sep 2008 07:26 pm

more developments (or less)...

the black smoke is still rife - i've replaced the idle solenoid, float valve and float, carb top, gaskets and so on. the car is smoother at tick over but belches black smoke coming off idle and spits soot out. is this likely to be a symptom of it being fixed but full of soot that will slowly clear?

Post by **pettaw** » 27 Sep 2008 07:52 am

No, it sounds like the float height is incorrectly set. Did you readjust the float height when you replaced the float and needle?