ausmini :: View topic - Problems With First Start

I'm having a bit of an odd-ish (to me) fuelling issue.

I have changed to a BBB needle, which is now providing quite a nice AFR ratio in the mid range and at cruise, and at wot it is also pretty good... that is, until about 4500-5000rpm, at this point it starts to lean out quite a bit. The weird thing about it is that it leans out up there regardless of whether I'm using what or 3/4 throttle.

Can anyone provide any insight into the possible cause of this?

And a possible solution? I am looking at either a BAZ or BAL needle, but they both then lean out that mid range again. I could possibly get another BBB needle and alter the final stages to provide more fuel. I'm just a little confused that it's a engine revs thing not a throttle position thing.

I've also changed to NGK BP6ES's, and they are definitely less sooty than my 7's, they are still a little black after. I get the feeling that my idle mixture needs leaned out a touch, but that's hard to get right in conjunction with the rest of the range.

Needles I'm also considering are:

BBZ and BCJ, with the BCJ actually being the fore-runner at this point. I am nervous about what the effect of adding all of that extra richness in at the 3/4 ish range will be.

Author:	mailman [ Sun Apr 28, 2013 12:08 pm ]
Post subject:	Problems With First Start
Hey Guys and Girls, Today I finally had a go at starting the mini with a couple of (much more capable) mates helping me. We managed to get good oil pressure, and hold engine temperature reasonably well, although it was a bit stinky, but I'm assured that's the paint and excess oil from the rebuild etc. I had two problems. First, and most major, was a carb issue. The engine really struggled on it's (carb's) base settings. The engine is set at 9BTDC static and has a HIF44 with a BDL needle and cone filter. It was way under-fuelled (or over-aired), but ran beautifully with full choke. I fear I may have a small leak on the carb as there is a small hole on the base(?) of the carb that looks to have something broken off in it (green circle), is there some sort of standard vacuum take off there? Also, I know this is answered elsewhere, and I'll go searching after posting this, but what should I do with the pipe in the middle (orange square)? What are your thoughts, is it just a new needle required? I am going to remove the carb and have a good look through it to see what the possibilities are. Can you/ do you need to re-jet the HIF44, or is it only the needle and spring that need set/specified? The second problem is with the tachometer that I have wired up. No reading whatsoever on it. I know that the lights wire and earth wire are ok. Can someone/anyone with the know how have a look at this picture and let me know whether they think that this is a suitable connection for the "live" wire? If it is fine then there must be a break in on of the wires . It's the small black wire connecting to the spade below that thick-ish red wire. Correct for "live"?

Author:	BALLISTIC [ Sun Apr 28, 2013 4:18 pm ]
Post subject:
Got a feeling the "hole" thats in the green circle may have had the vac advance port there, find a way to block it if not in use. The other pipe is another that you need to block off if not being used, a rubber hose with a bolt will do the job. (from memory it originally ran back to the air filter housing, i could be mistaken). This should eliminate the need for the choke to be used when engine running. The tacho thing im not sure of, are you using a dissy or coil pack?

Author:	mailman [ Sun Apr 28, 2013 5:35 pm ]
Post subject:
Thanks Ballistic. The green hole is definitely the Vac advance tube, I've just moments ago found a picture on google that shows it. I don't really know how to block it just yet. Will have to see what's in there and whether it'll come out. I am running a coil set up.

Author:	BALLISTIC [ Sun Apr 28, 2013 6:10 pm ]
Post subject:
You may need to remove the carb from the manifold to get the rest of the vac advance tube out & seal it well enough. Not sure if you have a "Selleys" product called "kneed it" or similar? Id tru that. From memory you should be getting you tacho signal from the negative side of the coil but your tacho may need to be modified to suit electronic ignition.

Author:	mailman [ Mon Apr 29, 2013 9:35 am ]
Post subject:
Kneed It is exactly what I had thought, though I've got some, I've never used it. Hope it's simple enough. Looks it Just a quick update as well to provide a couple of additional photos.

ausmini https://www.ausmini.com/forums/

Problems With First Start https://www.ausmini.com/forums/viewtopic.php?f=5&t=81261	Page 1 of 2

Author:	mailman [ Fri May 17, 2013 7:04 am ]
Post subject:
So, I had another go at starting the engine yesterday. Holes were all sealed up (Knead it worked a treat thanks Ballistic), and a bit more richness dialled in. No choke needed now but still doesn't seem quite right. Idle is set really high at the moment (about 1800-2000rpm) but the engine still doesn't like low revs. seems to struggle slightly to pick up as well. Does that sound like to lean or too rich? I took a short video. I have a Gunsons Colourtune and it indicates I'm getting closer. Am I still running to lean? http://youtu.be/7ga4VXiCtpM

Author:	drmini in aust [ Fri May 17, 2013 8:07 am ]
Post subject:
The port shown in the last pic is a PCV vacuum port, it is usually connected to the crankcase breather, NOT the air filter. If not using it plug it up as ballistic said. But they do work well at keeping enginey smells out of the cabin.

Author:	TheMiniMan [ Fri May 17, 2013 8:36 am ]
Post subject:
no Doc,,, he has the breather one connected next to that pipe, that pipe is actually the fuel float bowl vent tube,,, it can stay open or go to some filter or charcoal canister of some such it`s just the float bowl vent,,, don`t block it off!!!

Author:	minimy [ Fri May 17, 2013 5:54 pm ]
Post subject:
what miniman said,if you block this pipe it will eventually stall the motor..

Author:	drmini in aust [ Fri May 17, 2013 7:12 pm ]
Post subject:
Ah OK my bad, I never owned an HIF carb- I like HS6 better (because I'm an old bastard) It looked like an HS6 vac port.... [edit] why don't they label these ports... you should not need a road map to hook any carby up!

Author:	mailman [ Tue May 28, 2013 10:22 am ]
Post subject:
Ok, further to my previous problems I have now come across an odd one that I don't really understand. I've had my mini on the road now, it starts and drives ok but is running pretty lean. My problem now is that as I adjust the screw to alter the jet height it seems to lean off in both directions (of the screw - CW and CCW). I don't understand how this could even be physically possible. But, I thought I'd post here in the hope that someone may have seen this problem before and may be able to point me in the right sort of direction. My first port of call (after posting this obviously) is to remove the dashpot and see if the jet is going up and down with the screw, if it is I don't really know what to do next. And to be honest if it is I don't know what to do except maybe give it a blast with some compressed air (?) to clear out the jet and bowl etc. I have had the carb apart and it appeared to be in good clean condition, I put in a new jet, I am under the impression there is only one available, is that right?

Author:	mailman [ Tue Aug 20, 2013 10:15 am ]
Post subject:
I'm having a bit of an odd-ish (to me) fuelling issue. I have changed to a BBB needle, which is now providing quite a nice AFR ratio in the mid range and at cruise, and at wot it is also pretty good... that is, until about 4500-5000rpm, at this point it starts to lean out quite a bit. The weird thing about it is that it leans out up there regardless of whether I'm using what or 3/4 throttle. Can anyone provide any insight into the possible cause of this? And a possible solution? I am looking at either a BAZ or BAL needle, but they both then lean out that mid range again. I could possibly get another BBB needle and alter the final stages to provide more fuel. I'm just a little confused that it's a engine revs thing not a throttle position thing. I've also changed to NGK BP6ES's, and they are definitely less sooty than my 7's, they are still a little black after. I get the feeling that my idle mixture needs leaned out a touch, but that's hard to get right in conjunction with the rest of the range. Needles I'm also considering are: BBZ and BCJ, with the BCJ actually being the fore-runner at this point. I am nervous about what the effect of adding all of that extra richness in at the 3/4 ish range will be.

Author:	9YaTaH [ Tue Aug 20, 2013 12:48 pm ]
Post subject:
drmini in aust wrote: (because I'm an old bastard) Geez Doc, I hope your not looking for arguments there

Author:	simon k [ Tue Aug 20, 2013 7:07 pm ]
Post subject:
mailman wrote: I'm having a bit of an odd-ish (to me) fuelling issue. I have changed to a BBB needle, which is now providing quite a nice AFR ratio in the mid range and at cruise, and at wot it is also pretty good... that is, until about 4500-5000rpm, at this point it starts to lean out quite a bit. The weird thing about it is that it leans out up there regardless of whether I'm using what or 3/4 throttle. Can anyone provide any insight into the possible cause of this? the engine's demand for air is what sucks the piston open, the butterfly is there to limit how much air it's actually getting. With a big carb, there's not really a lot of difference between how much the engine can get through the carb between WOT and 3/4 throttle mailman wrote: And a possible solution? I am looking at either a BAZ or BAL needle, but they both then lean out that mid range again. I could possibly get another BBB needle and alter the final stages to provide more fuel. I'm just a little confused that it's a engine revs thing not a throttle position thing. you could also look at a BDG, it looks leaner than BBB at low & cruise openings, but wind the jet down a bit to put it in the same low & cruise range as your BBB, and you'll get richer at the bigger openings http://www.morrismini.com/SUNeedlesV2.a ... &size=.100 mailman wrote: I've also changed to NGK BP6ES's, and they are definitely less sooty than my 7's, they are still a little black after. I get the feeling that my idle mixture needs leaned out a touch, but that's hard to get right in conjunction with the rest of the range. 7's shouldn't have been in there in the first place - 6's are the starting point, I use 5's mailman wrote: Needles I'm also considering are: BBZ and BCJ, with the BCJ actually being the fore-runner at this point. I am nervous about what the effect of adding all of that extra richness in at the 3/4 ish range will be. BCJ looks the opposite of what you want.... I'd sand a little off the tip of your BBB if I was you.

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Author:	mailman [ Tue Aug 20, 2013 7:30 pm ]
Post subject:
Awesome, thanks so much! I will definitely compare those needles and see if I can get one. I will try modding the BBB, the hard part will be working out where to rub. Yea, I realise that now embarassingly. I thought that raising my comp ratio required the 7's but obviously their for more lairy engines than mine . Do you think a change in air filter would help in any way? I have a minisport cone on there at the mo. I may look to get an HIF44 elbow from the UK, if I can find one, so that I can use the normal airbox?