Series 3, running problem, help needed please

Since my last topics on here ive only just got round to getting the series out for a run since head gasket change and all the over heating problems.The main thing been the over heating problem has been cured, but now another problem is present.

Upon starting the series with full choke on, she will eventually fire after repeated attemps, but even with full choke on I have to let it warm up for ten minutes before touching the throttle or it will just die out . Anyway once its warmed up and a few miles down the road the choke can be pushed fully in and it will idle on its own and is ok when driving, the problem is if you just rev gently and slowly, it bogs down and goes to stall followed by a back fire.If you rev hard its fine,, this can be a bit of a nightmare especially in slow moving traffic and when setting off from a stand still, aswell as this problem the fuel consumption is through the roof,the 2.25 petrol isnt good at the best of times but its currently doing around the 9-10 mpg if not less..

Automatically I thought the carburettor was at fault, and took it to bits and cleaned eveything several times to no avail. So urgently needing a soloution to this problem bought a new webber 34ich from paddocks and fitted this evening,, and you've guessed it,, no change what so ever.

Im a bit lossed on what to do next, fuel pump maybe?

Your thoughts and advice is much appreciated yet again

Just to give you a bit more info,

The plugs have changed this evening also, its running a electronic distributor and sports coil, new leads,new fuel filter fitted which came with new carb,Timing has been checked.

anyone?

have u run a compression test since the head gasket change,
how did the old spark plugs look when they came out

109party said:

have u run a compression test since the head gasket change,
how did the old spark plugs look when they came out

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No havnt done a compression test, old plugs appeared maybe a little black/wet when removed.

the black is carbon from the plug failing to fire correctly, often caused by air and fuel mixture being too rich, other things are choke stuck on, wich you said u need. so its your fuel and air mixture, is my guess

Fitted the new carb this evening and messed around with it for severak hours, to no avail. Doesnt seem to solve the problem how ever I adjust it. Anything else I should check, and I'll crack on with it tommorrow. Thanks for the help

is the carb base warped or not sealed correctly ? (letting air in after the carb)

Sean said:

is the carb base warped or not sealed correctly ? (letting air in after the carb)

Click to expand...

No appears fine,, but will double check this tommorrow to 100% make sure. The carb now fitted is brand new and fresh out the box, and is giving the same symptoms as the old carb did, so im back at square one.

oiling on plugs is sticking valves, have you checked the air filter. the other thing is poor cylinder compression which would give you poor power output and slugishness, plus an engine thats not running right. oiling on the spark plugs is usualy badly worn valve stem seals, worn rings which would again take you back too poor compression. so a compression test is were to start, a visual quick rough check for cylinder compression it take the filler cap off while the engine is running if you get blow back the rings are worn. so thats one place to start

bowers1986 said:

No appears fine,, but will double check this tommorrow to 100% make sure. The carb now fitted is brand new and fresh out the box, and is giving the same symptoms as the old carb did, so im back at square one.

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sigh .........

how do you know the base (that your new carb is sat on) is truly flat ?

109party said:

oiling on plugs is sticking valves, have you checked the air filter. the other thing is poor cylinder compression which would give you poor power output and slugishness, plus an engine thats not running right. oiling on the spark plugs is usualy badly worn valve stem seals or valves, worn rings which would again take you back too poor compression. so a compression test is were to start, a visual quick rough check for cylinder compression it take the filler cap off while the engine is running if you get blow back the rings are worn. so thats one place to start

Click to expand...

The air filter is a K&N thing just bolted to top of carb and all appears fine? what should I be checking for, just tight fitment?

Will remove filler cap tommorrow and see what I find, thanks for the advice.

Sean said:

sigh .........

how do you know the base (that your new carb is sat on) is truly flat ?

Click to expand...

ahh good point, i was assuming you meant the base of the carb itself,rather than the base the carb sits on.

bowers1986 said:

The air filter is a K&N thing just bolted to top of carb and all appears fine? what should I be checking for, just tight fitment?

Will remove filler cap tommorrow and see what I find, thanks for the advice.

Click to expand...

something that would look like its going to reduce the flow, maybe blocked, does it run better without it, how old is it

109party said:

something that would look like its going to reduce the flow, maybe blocked, does it run better without it, how old is it

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No change in running with it on or off really.

so its further down, check the compression even if its roughly done by removing the oil filler cap. if you can get hold of a proper compression tester run it wet and dry and see of there is any change

op2:

Fundamentals to start with.

1. If the engine idles OK.

2. If the engine pulls hard with large throttle openings.

You can pretty much eliminate all the crap and stick with a carburettor/inlet leak issue.

Dont look so hard for problems. If your description of the problem is accurate the carb is you only issue. Find the problem and dont let anything deviate you from the real problem.

For information the transition jets of replacement carbs are smaller than the idle jets. Very slight opening of the throttle will result in ultra lean running and will often cut out.

1.You need to check air leaks from below the carb, advance retard pipes split, vacuum pipes to servos, engine breather pipes and valves etc.
2.Remove any crappy non standard air filter you have fitted for problem solving.
3.Check and set idle mixture screw. Vacuum gauge, CO2 analyzer or a real mechanics ear will get that right for you.

Now if you still have the light throttle cutting out you have blocked transitional jets. Period!!! Cant find the blockage? Get over it and look harder.
Fitting a new carb with dirt and **** in the fuel lines means that often a DIY mechanic will just foul up a brand new carb and scream that wasnt the problem.
This is a very common problem with Webber replacement carbs. You must use an airline and remove jets and plugs to remove the blockage and then USE A PAPER FILTER in line just before the carb. The screen filters in the fuel pump let too much crap through to the carb. Strip out a carb and see the crap in the float bowl if you want to see how much.

Do this and you WILL find the problem.

Oh yea. If you use an airline in the wrong place keep your eyes open for projectiles fireing from your carb. You probably will need them back LOL.

spitfiremk1uk said:

Fundamentals to start with.

1. If the engine idles OK.

2. If the engine pulls hard with large throttle openings.

You can pretty much eliminate all the crap and stick with a carburettor/inlet leak issue.

Dont look so hard for problems. If your description of the problem is accurate the carb is you only issue. Find the problem and dont let anything deviate you from the real problem.

For information the transition jets of replacement carbs are smaller than the idle jets. Very slight opening of the throttle will result in ultra lean running and will often cut out.

1.You need to check air leaks from below the carb, advance retard pipes split, vacuum pipes to servos, engine breather pipes and valves etc.
2.Remove any crappy non standard air filter you have fitted for problem solving.
3.Check and set idle mixture screw. Vacuum gauge, CO2 analyzer or a real mechanics ear will get that right for you.

Now if you still have the light throttle cutting out you have blocked transitional jets. Period!!! Cant find the blockage? Get over it and look harder.
Fitting a new carb with dirt and **** in the fuel lines means that often a DIY mechanic will just foul up a brand new carb and scream that wasnt the problem.
This is a very common problem with Webber replacement carbs. You must use an airline and remove jets and plugs to remove the blockage and then USE A PAPER FILTER in line just before the carb. The screen filters in the fuel pump let too much crap through to the carb. Strip out a carb and see the crap in the float bowl if you want to see how much.

Do this and you WILL find the problem.

Oh yea. If you use an airline in the wrong place keep your eyes open for projectiles fireing from your carb. You probably will need them back LOL.

Click to expand...

:doh:

allo allo allo

Just to give you an update on the situation, re read this post this morning and cracked on with some of the things suggested.

Tightened all nuts/bolts down on carb, lift pump etc,, some were quite slack which suprised me. Anyway proceeded to set carb up as explained in instructions booklet from webber, found while the choke was pulled out it would rev normally,,even pressing the throttle very slowly and gently wouldnt make it stall like before, so thought I was getting some where. Anyway played round with it a bit more, and accidently knocked the emission control pipe off which goes from oil filler to just below carb, anyway I put my finger over end of tube and found the engine quietened down and ran 100% (better than ever to be honest) but once finger was removed returned to running alot louder and lumpy like previousley. Refitted the pipe and tightened every thing up but still ran as before. Anyway in the end I removed the pipe again and put a bolt in end and tightened it up with a jubilee clip making it air tight. Set carb up while it was running so good and its now better than its ever been,,,sounds like a sewing machine and doesnt miss a beat and the problem of going to stall when gently/slowly reving has disapeared completly and it drives 100%.

Should I just leave it like this or start replacing the emission control system/pipe/diaphram? is it crital to have it installed?

will await your advice- thanks all