Are the connections correct?
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7 = Fuel inlet
8 = overflow vent - can have a length of tube open to atmosphere connected to it
11 = crankcase ventilation to either tappet cover or timing cover canister. It was never connected to the rocker cover as part of an original design.
All the connections, including throttle and choke, can be on the opposite side of the carb, depends on the original application.
Richard, thanks for that diagram looking at it my connections are right, but its always good to be sure. Roy stuck float could be very possible as i only gave the carb a cosmetic clean with carb cleaner and a wash in WD40 before drying it off, the piston was free but had no oil in as it has been left on its side in a plastic bag for a while, i topped up the dash pot and it and it felt smooth moving, I used 3 in 1 oil if that is wrong i will clean it out as it looks like i will be opening the carb up now.
3-in-1 oil will be fine, and if the piston rises and drops smoothly, all is fine in that area. I take it it is fitted with a needle and jet? Raise the piston to check.
Yes chipper it has a needle and jet, It came off 1989 mini cooper running engine but that was 3 years ago and it has been stored but kept clean from bits. I have cleaned up carbs before and rebuilt them but never an SU so i really must get into it, I see online some alternative jets and needles so it will be usefull to have a knowledge.
Try running it a bit with petrol dribbling down it's throat - the suction and vibration may just free up the float if it's stuck. I assume the pump is delivering fuel ok?
Yes Roy the pump works fine, it came with the car and it is one of those modern SU pumps with the electronic control not points, i used it to drain most of the old petrol from the tank which had a smell like cat urine.
Yes it was a stuck float valve Roy, it ended up cleaning it all out with thinners as it was aall covered in black gunge, it runs just as it did before same engine problem so now i am moving onto the dizzy , The HIF was not hard to clean out and came appart easy.
Roy it runs just as it did before , it hunts up and down but i had a spare few hours today so i did a dizzy clean up, it was damaged where the clamp had been over tightened, I ended up making a good dizzy from 2 others i have not tested it yet, i did find this quite interesting http://mgaguru.com/mgtech/ignition/pdf/ ... s_dist.pdf
Indeed, of course - you really need a dyno or a rolling road to set it up perfectly -or much tedious road-testing. A C Dodd seems to have the dizzy setting business down to a fine art. But your main interest at the moment is to get the engine running well, and not pinking. I prefer to set with minimum static advance (for easiest starting) and then let the vacuum and bob-weights pull it up as the revs increase. I would have thought 'hunting' would be an air leak - but maybe it is coming on and off the vacuum advance system... Anyway - no harm getting the dizzy as good as you can !
Good news, it runs ok with the new dizzy, i have taken out the alarm and rev counter, i did have a few problems which seemed to go after i took out the rev counter, It idles better and ticks over around 900 rpm, The timing light has still not turned up but till it does i have an air filter to fit as it just has the elbow at the moment, but i am happy at the single carb swap and dizzy clean up.
Last edited by olderisbetter on Sun Jul 03, 2016 12:07 am, edited 1 time in total.
Thats pretty much how it has been done, and i know the strobe will not be of use as i guess i have no reference points but i;m sure it will be usefull for something.
At least with a strobe you can see that you have advance and what the advance is.
Whilst you may not have timing marks you can always paint them on
Phil
Hi Guys
When I got my car home from the dyno tuning session I decided to record the ignition timing for future reference. The timing light I used was an 'advanced' timing unit where it can show TDC pulley mark and TDC reference marks. When the advance facility is used to coincide the TDC pulley mark with TDC reference mark the advance is displayed in degrees on the display panel. This display is in units of 0.5 deg. In the case where I need to do something to the motor which changes this reference it is easy to use the timing light to revert to the original setting without having to go through the tedious proceedure of 'best idle' then 'pinking test' when driven especially with high frequency hearing loss. I would never consider using my car with a blown pressure of 15.2 PSI without knowing that my timing was right for fear of melting pistons or burning out valves. https://www.amazon.com/INNOVA-5568-Pro- ... B000EVU8J8
