Return of the hesitation...

Hi all,

when im at higher speeds accelerating i feeling a loss of power/judder or hesitation causing me to slow down and pull over into the slow lane..
Looked at my dizzy just from the outside and noticed a slight oil leak.
think this may have caused the return of my recent timing problem?

thanks
cf_emoticons__BangHead:

It sounds a bit more like an airleak on the carb/manifold, could be the dizzie shaft though. when the engines idling spray some quick start or another flammible spray around the carb/ intake manifold and listen carefully if the revs pick up then you have an air leak

Ok Thankyou, ill have a look this evening and report back!

I had a look, sprayed some carb cleaner in the top….
Then noticed the carb cleaner leaking out of the base of the carb and onto the manifold..

So i think this 4 month old GSF quality part is now split..

Think that may be my problem?!





cf_emoticons__BangHead:

rather than spray it into the carb spray it around the outside of the gasket/manifold. If theres a gap the the flammable vapour with be drawn in and your revs will pick up. but if theres something leaking from the gasket anyway then yeah, it sounds the the gasket has gone. the problem you described sounded typical of an air leak too

Ok Thanks ill have a closer look this weekend and report back!

I find a card or fibre gasket betweeen the carb and manifold seals better and fails less often than the originnal rubber base..

oil leaks past the base of the dizzy when the o-rinng fails, shouldnt affect the timng though unless the dizzy itself is knackered.

does it happen if you're cruising along the motorway and put your foot down to overtake?  or if you've been accelerating for a long time, up a big hill for example?  is it always at a certain engine speed or a certain throttle position? when did you last change your fuel filter? does the hot air flap work correctly?  it could be a few things, need a bit more info really..

Yes it does happen when cruising and performing an overtake, and when accelerating for prolonged periods. Sounds spot on, seems like in regard to accelerator positioning is when the second chamber opens on the carb (about midway) 

I've replaced the carb flange also this past weekend still does it. 

Any ideas?

if its about halfway thorough the pedal travel theres a chance that one of the circuits in that barrel is blocked, or maybe the pump jet doesnt work, it might be a lean stutter that you could sort out with a small flat blade screwdriverr..

 you should take it to your garage and ask if you can use the gas tester in the MOT bay for a few miniutes, offer to chuck the guy a tenner if you need to - I did this after fitting my weber and at first my CO was 8.3%!! which explained a lot of my drivability troubles, tweaked it down to 1.8 at idle and it drives like a dream!

have you checked your float level? or fuel pump?   one 'quick and dirty' test you can try is to blank off the fuel return and go for a drive, if ts fixed it you can look at the pump and float, if not then your issue lies with either jetting, dirt, or timing..

Ok Thankyou for this advice mate. I'm stripping down the carb on Thursday, bit ill try the test you suggest before hand!

Ill let you know my progress, thanks!

Just a question… How do you check the float level mate and what should it be at? 

Thanks

is your carb a DTML or a TLP? either way the float sits on a pivoting arm in the fuel bowl and it has a needle on top to close the hole where fuel comes into the bowl when the float - which floats ontop of the fuel - gets to the set height..if the level is too low you can suck all the fuel out of the bowl and most of what comesfrom the pump goes down the return.. as for setting i'd go with trial and error at first making adkustment, going for a little drive, more adjustmetnt, more driving etc..its not always definitely right but i'm chasing a problem like that i'll do it 3 or 4 times and if theres no improvement i'm chasing the wrong thing so i put it back to where it was and look elsewhere.
and definitely get it on a gas analyser - that'll tell you everything you need to know if you can be arsed getting down with this science… http://www.autoshop101.com/forms/h56.pdf

Just to be more specific of the problem, it's when the second throttle valve opens and prolonged acceleration or sudden happens. It will then start to hesitate.

MK1Morley said

Just to be more specific of the problem, it's when the second throttle valve opens and prolonged acceleration or sudden happens. It will then start to hesitate.

sounds like its going lean on the main circuit in the second barrel…best way to confirm this is to get it on a gas analyser - did you read the link I posted in my previouus comment?   read through that and get it on a gas sniffer!

Will do mate!

Just an update,
Stripped the carb, cleaned all that could be cleaned!

And still no success, 

A perfect description of the problem is prolonged acceleration opening the second throttle chamber on most occasions causes it to splutter. And during the "spluttering/hesitation" it will pop and spit from the exhaust.

I'm getting fed up of the clipper now and I really don't want to be

Looked at the spark plugs, there white. LEAN!!!arghhh!!! 
So I adjusted the mixture and it still does t stop the problem, I'm going to block off th return next…. If this works. Faulty fuel pump maybe??

Thanks

SUCCESS return clamped off and she runs like a dream… Hmm now to actually find out what's not working!

MK1Morley said

SUCCESS return clamped off and she runs like a dream… Hmm now to actually find out what's not working!

I've done the pump and still no success … next I'm thinking the filler and tank need to get changed, I'll be changing the vapours operator too- convinced its crud in the tank.

Where did you tap the return thinking of trying this first but don't want to ruin things- have you got a pic?

I literally got a set a grips and clamped onto the return from the swirl pot and went for a drive! I'm thinking my problem is the pump! I will get a pic ASAP

MK1Morley said

I literally got a set a grips and clamped onto the return from the swirl pot and went for a drive! I'm thinking my problem is the pump! I will get a pic ASAP

Cheers mate. Just had my pump changed so thinking rust or if not, the return is having an impact….somehow…