Acceleration stops at 50mph - max speed=50mph

[johnfrancis898]

I have to agree with Johnnydog. My car is never laid up for more than 3 months. I never take it out on wet or salty roads so from end of November until March I rarely open the garage. It always starts ok and I’ve never had any fuel issues. I always clean the carb chambers out and fit a new fuel filter as part of the annual full service.

[Forkie]

I think i may have muddled the fuels - the 'new' fuel is the E10, the E5 now being the 'old' unleaded - is that correct?! And also, is it the new E10 that introduces water to the system over time, but the E5 does not , which means a few months left in the tank should not give any issues - is that also correct?

[johnfrancis898]

I think you are worrying too much Forkie.
Use a good quality fuel with a good additive and you will be fine.

[johnnydog]

E5 fuels have a 5% ethanol content, whereas E10 fuels have a 10% ethanol content. Ethanol is very corrosive and can adversely affect the components of an older fuel system if not compatible - therefore using a higher grade fuel (super unleaded 97-99 RON (octane)) is better for your Triumph as it has a lower ethanol content. Using an 'e' rated fuel additive helps protect components against the effects of ethanol, gives protection against valve seat recession and increases the octane /RON rating by up to 2 points. Don't forget, the PI for example was originally designed to run on the old 5 star (100 octane) fuel, so using the best quality fuel with an additive can in my opinion only be a good thing. Some say that they have run their Triumphs for years on E10 with no adverse affects, but for the additional cost spread over the usage over the year, for me 'it's a no brainer' as they say.
My Triumphs and my Vauxhall Omegas (3.2 V6 petrol engines) all run noticeably better on this E5 99 RON Super Unleaded fuel.

[Forkie]

So the reason for asking was to check which fuel absorbs water, i just got a bit muddled which was which as i seem to be having some kind of starting/ running issue all of a sudden so i think i panicked a tad and thought ' water contamination', which now i realise will not be the case as i use non -supermarket E5. Since being back on the road we have it out at least monthly, but with the poor weather and onset of 'that' time of year she not been out for a couple of months, so a few days ago we thought we will just fire it up, get to temperature etc. After doing the king lead removal, prime the fuel and no choke crank over until the oil light goes out ( which i do each time if left for a while) , reinstated the king lead, choke out and go - she did not want to start - normally it is pretty much instant - took way to many cranks, and even then only eventually spluttering to a run - and only barely 1000 rpm. Then, once warm it just sounds a tad uneven, not right at all. Some checks to be done i think. The reason i was querrying the fuel is nothing should of changed in a few months....
I have been offered a loan of a Gunsons colourtune kit, i think i may as well try it. I've never been that convinced it was properly set up last year, at least that kit should give some kind of idea.

[Forkie]

So having gone back out last night to do a few checks etc - choke operation seemed normal - why did it not start well? So we deduced the lad had not pulled the choke out fully - i am trying to teach him the basics of starting the old girl - maybe i need a slap there for not checking in the gloom of the garage that it was fully open - it gets tight, then needs the extra pull which he did not realise. So last nights start up was much better, on the key with keen idle at cold. But regarding idle once warmed up is still uneven. Checked the plugs - num 2 looked pail. Num 5 black. So on that i assume front carb a tad weak , the rear rich. Uneven idle. Car feels lumpy, rocky almost when sat in . Spitty sound from the SS exhaust. A slight miss , bit not an even miss- every so often . Not a smooth idle in any case.

[johnnydog]

The difficulty you outlined in pulling the choke out is an issue that I was shown many years ago by an 'old school' chap who was very experienced with Strombergs - the Mk1 more than the Mk2 suffered from this which also included problems in pushing the choke back in. Apparantly the profile of the fast idle cam was such that there was some resistance part way through its travel. A bit of reprofiling with a file made the profile more constant, and on my Royal Blue Mk1 it certainly eliminated this resistance when pulling out the choke.
The original Mk1 choke cable was in two halves; joined by a small section of rubber tube / hose with internal star washers at either end. When pulling out the choke, the outer cable often separated at this joint, and combined with the severe fast idle cam profile, the cable didn't return when the choke was pushed in, effectively leaving the choke 'out'. This original choke cable was often replaced by the later one piece cable with the plastic outer sheathing to eliminate this.....

[Forkie]

Interesting point John - though mine are SU HS6 types, i wonder if the cams are a similar profile. I have always wondered why the last quarter inch or so to pull out appears much tighter. The return, as in the choke off action is fine - no issues - in fact it is almost in reverse when i think on - the last quarter push in ' to home' does not appear to do anything, as in i can tell when the choke is fully off, idle speed is down to around 600/700, but there is always a little bit of ' slack ' cable as it were to fully push the knob home. On doing that, nothing happens to the idle - so as i see it - the last quarter push in does nothing to the idle.
Going back to the carb settings - could you confirm that going in from ABOVE the carbs - to WEAKEN the mixture, the nut needs to be turned ANTI CLOCKWISE.....

[johnnydog]

Apologies, I'd got it in my head your car had Strombergs.
The problem I outlined re the fast idle cam profile was really only relative to Strombergs, not SU's.
Yes, to weaken the mixture, the mixture nut needs to be turned anticlockwise (to raise the jet) when viewed from above.

[Forkie]

Thank you for the confirmation on that. Im going to have a go at balancing the carbs myself, not something ive ever done but at the same time i am not convinced on the view of a few others that they are correctly set.
A Happy New Year to all !!!