help carb tuning 850
Orig. Posting Date | User Name | Edit Date |
May 6, 2019 02:10AM | AWOODY | |
May 5, 2019 10:45PM | malsal | Edited: May 6, 2019 08:43AM |
May 5, 2019 06:11PM | travellering | Edited: May 5, 2019 06:15PM |
May 5, 2019 06:01PM | travellering | |
May 5, 2019 01:17PM | malsal | |
May 5, 2019 06:59AM | thewerewolf | |
May 5, 2019 05:58AM | travellering | |
May 5, 2019 02:11AM | Alex | |
May 4, 2019 06:57PM | thewerewolf | |
May 4, 2019 06:15PM | travellering |
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You maybe got lucky with the other parts installed sometimes you can turn the top around 180 degrees and they end up being centered easier.
When you install the new jet center the jet with the spring and adjusting nut removed also dont install the jet tube in the float chamber until final assembly.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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A new jet assembly will be ordered Monday, and then i can get back to the other list of stuff to fix on the car....
rusted subframe bolts are the hardest material known to man...
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Removed the box pump, moved the working MrGasket Micro pump down to closer to the tank, and hey, look, the fuel filter is full, and now we have enough gas to foul the plugs again...
rusted subframe bolts are the hardest material known to man...
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BPR 6ES or N9Y plugs should be fine in an 850.
Make sure everything is set correctly points, plugs, vaves timing etc before touching carb adjustments.
Also check that the mechanical advance is working on the dizzy.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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- The last set of plugs i put in were NGK BPR6ES. I will see if any of the local stores have a hotter plug to try.
- I have another carb with the correct needle (EB) in it, but that carb was given to me as "in need of a rebuild", and the choke cable attachment is different, so just popping it on there isn't likely to improve things much...
rusted subframe bolts are the hardest material known to man...
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Fit a new jet and centre it properly. Look up in the Book of Words the correct needle for a standard 850 and fit one. (Order direct from Burlen).
Set the jet 15 flats down from flush as per the manual.
With the engine running check the vacuum advance & retard unit is working correctly.
Set the timing with a strobe and the vac disconnected.
What plugs are you running ?
Sounds like they may not be hot enough and are fouling at tickover.
I'd have thought that a NGK BP5 (maybe a borderline 6 but no colder) or a Champion N9YC would be suitable.
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I took the dashpot cover and needle housing out, and the needle looks to have been sanded on at some point in its history, but could not find the identifying numbers on it anywhere. Once lined up on the keyway, the piston drops to the bridge with a clunk, so it's not obviously sticking there.
The choke is sticking on occasionally, but I can pop it up the last tenth of an inch by hand and have done so before any of the testing/adjustment.
When it is idling-using a borrowed Gunson colortune- it is showing yellow= rich, but the moment I move the accelerator even the slightest bit, it goes bright blue, so the mix can't be miles out. Using the lifting pin yields not much more help, as it seems half the time it accelerates slightly, and the other half (especially if it is woofling) it slows down to the point of dying. Is the lifting pin supposed to be a momentary thing, or should I be holding it up when looking for the results? So far I have been holding it up, as just popping the pin up and letting go gave no change in engine behaviour.
It is on a Mr. Gasket electric pump, and on the theory that the pump was overfilling the float bowl with too much pressure, I have fitted a pressure regulator and gauge which verifies it is at 3 psi running. Fuel is fresh and recently topped up, no vacuum leaks are in evidence (tested with carb cleaner spray around both ends of butterfly valve, and around manifold to carb junctions. The fitting at the end of the vacuum advance line at dizzy was cracked, so that has been replaced).
rusted subframe bolts are the hardest material known to man...