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Post by Talking Hoarse on Jul 25, 2018 17:19:33 GMT 1
The old Datsun has been misbehaving - it was running really well a couple of weeks ago but had started running rough & lumpy after I refilled with fuel, especially between 2000-3000rpm. I have probably used all of that fuel by now but fault persists.
I had initially checked & cleaned the points - all well of course but no improvement.
Then after a further run I found the plugs were sooted & black. But the crank breather is dry (it doesn't use oil). When I peep down the air intake the choke flap is open (ie not restricting air flow) - I have already mostly backed off the auto choke. On a long run at the weekend, I estimate about 15-20mpg that is well out of sorts as well as out of my pay grade, and dropping to 2 or 3 cylinders as if flooded at times. Notwithstanding that it will sit and idle quite happily.
The float level is about midway up the glass peep hole.
Anyway - took me a morning to get the carb off, and have dismantled and cleaned and reassembled. It was spotless clean inside, and nothing seemed loose or perished so no fault found.
However I have tried the car again but it is still running very very rich with a black sooty exhaust, and at least one black sooted (but not wet) spark plug. Seems to still run OK at idle, and moderately on 2nd choke.
I believe the carb is a 1983 NIKKI 21A304-341
Help!!
Who can help me?
Ed
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Post by antdat on Jul 25, 2018 17:31:30 GMT 1
Might want to take the top off the carb and check all the jets are tight, I had this issue years ago on my L20B
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Post by Talking Hoarse on Jul 25, 2018 19:31:40 GMT 1
Might want to take the top off the carb and check all the jets are tight, I had this issue years ago on my L20B Thanks for prompt response - Yes I did and they are. Also the 2x main jets in lower body of float chamber. Ed |
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Post by antdat on Jul 26, 2018 6:31:34 GMT 1
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Post by Talking Hoarse on Jul 26, 2018 13:07:26 GMT 1
Thanks Antdat for the detailed response. I am no expert, but I think I got to all the potential bits and cleaned and reseated them. My carb is similar but (likely) a later model /with more gubbins attached to yours in the pics.
Anyone suggest where I get a service kit (for Nikki 21A304-341?) from?
And ….can anyone suggest someone more expert /practiced than I in rebuild of a Nikki carb?
Thanks
Ed
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Post by antdat on Jul 26, 2018 17:30:13 GMT 1
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Post by Talking Hoarse on Jul 26, 2018 19:21:09 GMT 1
Thanks again - yes I spotted that but its for older model car & carb, so I would be taking a chance that the bits fit my carb. Ed |
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Post by antdat on Jul 26, 2018 22:46:57 GMT 1
the carbs didn't change much, the more modern one had electric shock and anti run on (my L20B has the modern carb) i'm not saying all the bits will fit but it looks like the same kits i have used in the past of various L series carbs and they tend to cover a few different ones.
and for £20 you cant really go wrong.
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Post by Talking Hoarse on Jul 28, 2018 16:51:32 GMT 1
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Post by Talking Hoarse on Aug 15, 2018 6:44:43 GMT 1
It seemed like a good plan, but thwarted when Amayama then cancelled the order for all 3 service kits as now unobtainable.
So I followed my "bladder feelings", and also some advice offered and:
- blew back the return pipe to the tank (my carb has 2 fuel pipes, a fuel feed from pump, and a return for unwanted fuel to tank)
- proved that the needle valve stops flow
- confirmed that the fuel level in float chamber remains steady when engine running. And as the level was at the upper edge of the marker dot in the fuel chamber window, I adjusted so as the level is at the lower edge of that dot. (I had no success measuring the gap with feelers or a drill bit whilst carb was in situ).
Now the car runs so much better, and doesn't foul the (now clean) plugs. Still runs uneven at about 2000rpm. So retaxed it and will use it for a few long runs over next few weeks to hopefully clean all the soot that has accumulated. Then work through the cam clearances, replace fuel and air filters, plugs, points, rotor arm and distributor cap as I have these parts to hand. Then I will take it to a friendly garage for a sniff so there are no nasty surprises with emissions when it gets to MOT time.
So I dont think I ever got to root cause, but its all now looking good, back in use and work in progress.....
Ed
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paranoid
club Member
datsuns and old british cars wanted for breaking
Posts: 152
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Post by paranoid on Aug 17, 2018 0:15:13 GMT 1
Potential blocked jets
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Post by Talking Hoarse on Aug 23, 2018 18:18:22 GMT 1
Some time has passed, some work /effort but sadly no progress.
Still runs like cr@p, very rich but will sit and idle OKish.
The service kit(s) I ordered from Japan never came - the order was cancelled as parts no longer available!!
However I am now eagerly awaiting a Meat & Doria service kit from Autodoc.co.uk, for about £30. I have also tracked down a Weber conversion kit, but that seems to clock in at over £300 whioch is well beyond my pay grade for the heap.
What I did trip over, is that this carb seems otherwise described as a Nikki DCH340, and appears to share service kits with some Hitachi carbs, so I wonder if there was link between Nikki & Hitachi.
So - no real progress, and still hunting for a sympathetic carb person within 50 or so miles...…
Ed
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Post by spottedlaurel on Aug 26, 2018 8:17:58 GMT 1
When I struggled with carb issues on my 1200 I got one of those Meat & Doria rebuild kits. I was a bit sceptical about the quality of it, but it did the job just fine.
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Post by Talking Hoarse on Sept 22, 2018 12:26:53 GMT 1
YIPPEE - SORTED AT LAST!!
I did receive the Meat & Doria service kit from Autodoc (took about a week to arrive from Germany). I was reluctant to open up the carb yet again without expertise or plan, so engaged Central Motors Cheltenham to sort. Recommended to them by an retired /veteran local mechanic. They seem to specialise in air cooled VW's but have all variety of work in, and a tidy organised workshop. Expecting the work to be entrusted to an old timer (ie familiar with 30+ year old carbs) I was delighted it was sorted by young Craig - who enthusiastically dismantled, sonic cleaned and rebuilt.
Bill paid, and all now seems well again at last. Root cause was inconclusive, probably muck and a batch of dodgy supermarket fuel.
The M & D kit was a bit alarming as it referred to a Hitachi carb - although the diagram looked just like my own Nikki - but clearly many of the bits inside fitted correctly.
So the heap is back in action once again, and I can now get on with all the other jobs lined up for it, having got this step forward.
Thanks again for contributions.
Ed
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Post by gainsb1 on Sept 23, 2018 12:21:26 GMT 1
Nice one, Ed. I was hoping that your tale of woe would point me in the right direction for my similar issues. Despite the tweaking etc. mine is still playing up (running too rich and super rich at 3000rpm) but I did visit Will and I now have a second hand carb that I have also had sonic cleaned but am awaiting for it to be fitted. I'll let you know. Annoying, isn't it?
Leigh (Area rep)
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