Removing & Servicing a Carburettor - How hard is it?

Post by **philb** » Mon Oct 05, 2009 3:46 pm

Hi Guys

Contemplating spending my evening with the wife, a bottle of red wine & the carburettor out of her Morris Minor - Patsy.

Please can you advise me on how difficult it is to remove & strip down / clean a late type HS2 carburettor.

Also a step by step guide would be a great help on how to remove it from the vehicle & take it to bots....oh andput it back together again LOL:)

Patsy is smelling of fuel & drinking petrol whilst running badly, stalling and generally being horrid. She's had her points, condensor, HT leads, Plugs, Coil, Dist cap & rotor arm changed last Thursday and she was tuned on the weekend. Ra like a dream on Saturday afternoon....today however she's worse than ever.

I think there is an issue with the Carb

Post by **bmcecosse** » Mon Oct 05, 2009 3:50 pm

It's not difficult - but I suggest leave the red wine till afterwards! All the details you need are in the Workshop Manual - page BBB 4 onwards. I think there also some You-Tube episodes of carb stripping - may be worth watching. However - the carb really is a very reliable thing - the only possible item would be the fuel inlet valve in the float chamber - if it's leaking then that would make it run rich at idle and low revs. But unlikely to be ok one day - and not the next!

Post by **philb** » Mon Oct 05, 2009 4:44 pm

I just can't understand why she's playing up? It's a mystery.

You've read my other posts today...any thoughts about where to start looking?

Is there anything that could throw out the timing & mix? Perhaps something that's come loose or worn? A bad connection?

What would cause her to stop running, and have smell of petrol that wouldn't be solved by changing HT leads, points, dist cap, condensor, rotor arm, spark plugs, & coil?

What are we missing? Something else with the distributor perhaps?

Post by **bmcecosse** » Mon Oct 05, 2009 10:54 pm

Smell of petrol could be because there is no spark to burn it - or because the carb is flooding over. Are there any 'drips' under the carb if you sit with ignition on (don't do it for too long!) - and does the pump click away even though the engine is not running ?
What did the garage do at the 'tune up' ??? Only ignition item you haven't changed - seems to be the little 'low volts' wire inside the dizzy - and of course the lead too the coil - and from dizzy to coil. you could fit new 'temporary' leads just to see if that cures the problem. Also check if coil is on right way round (-ve to dizzy if -ve earth car) - and is it the correct coil? Check the resistance - should be ~ 3.2 Ohms between the two terminals.

Post by **David53** » Tue Oct 06, 2009 7:00 am

A smell of petrol usually indicates that petrol is leaking somewhere, or a VERY rich mixture - as BMC says check all the obvious places to see if any is dribbling out anywhere, including pump, the tank and fuel line from tank to pump.

When you turn ignition on do you get a nice fast click from the pump then slows to silence with only an occasional tick? If so this would tell you that the cutoff needle in the carb is sealing OK. Providing this is the case, and no petrol is leaking anywhere else you could then try winding the mixture nut all the way in (up) then back down about two turns and then gently adjust up and down until the engine runs smoothly. This will get your mixture basically right. Then make sure you have plenty of oil in the dashpot damper on top. The carb is a pretty simply device, not a lot to go wrong.

Post by **bmcecosse** » Tue Oct 06, 2009 7:31 am

No need for that surely ! The engine has just been 'tuned' at the garage!

Post by **philb** » Tue Oct 06, 2009 9:21 am

LOL:) bmcecosse!!

Found the problem, carb is worn. Running rich one minute & weak the next! Just playing about above the mixture nut under carb sends Patsy crazy

Will order rebuild kit today.

Thanks for all your help so far.

Post by **PSL184** » Tue Oct 06, 2009 9:26 am

Check it's not just the piston that is sticking first. Sounds like a hell of a lot of wear to have that much effect on overall running....

Post by **philb** » Tue Oct 06, 2009 10:32 am

There is alot of play in it.

Piston has been cleaned and oil well is clean and full.

Post by **PSL184** » Tue Oct 06, 2009 11:13 am

Jet nut tight? (not the adjuster - the securing nut)....

This may help you along.....

http://www.sucarb.co.uk/TechnicalDetail.aspx?id=35

Post by **David53** » Tue Oct 06, 2009 1:33 pm

Gee I'd be asking for a refund on that "Tune Up"..........

Before you go pulling the whole carb apart check the large nut that secures the jet assembly in the carb body. It's the big nut above the mixture nut and spring. Sounds to me like this has come loose somehow and the jet assembly is loose in the body. A quick tighten might solve the problem.

Post by **philb** » Tue Oct 06, 2009 2:15 pm

Will check Jet nut fastener tonight.
There was no charge for tune up as it was done by mechanic friend who has been working on Patsy. He's an enthusiast and very methodical and thorough.

Post by **PSL184** » Tue Oct 06, 2009 5:32 pm

David53 wrote: Before you go pulling the whole carb apart check the large nut that secures the jet assembly in the carb body. It's the big nut above the mixture nut and spring. Sounds to me like this has come loose somehow and the jet assembly is loose in the body. A quick tighten might solve the problem.

I'm sure that's what i said....

and quite likely loose cause someone has been using it as the mixture adjuster

Post by **David53** » Tue Oct 06, 2009 11:11 pm

I know

I only noticed your post after I'd sent mine! Doh!

Post by **PSL184** » Tue Oct 06, 2009 11:15 pm

No worries mate - I thought I was invisable for a while there

Good to know we are in unison though ;-)

Post by **philb** » Wed Oct 07, 2009 9:48 am

Checked the nut this morning...it's tight.

To be honest I was hoping I'd find it was loose!

Post by **David53** » Wed Oct 07, 2009 10:45 am

Found the problem, carb is worn. Running rich one minute & weak the next! Just playing about above the mixture nut under carb sends Patsy crazy icon_wink.gif

Well if i is loose with a "lot of play" but the nut is tight then it looks like you'll need to strip it down and rebuild as for some reason the jet assembly is loose or not seating properly. Good luck!

Post by **philb** » Wed Oct 07, 2009 2:17 pm

Is it a difficult task? My wife is not keen to let me do it. Worried I might mess it up.

I have a rebuild kit & new needle. Is it easy to remove carb from car? I have a step by step guide that another forum member posted to me.

How fiddly is it & how long is it likely to take?

Post by **PSL184** » Wed Oct 07, 2009 5:31 pm

Certainly sounds extremely worn (suprising more so than any other I've seen). Maybe someone has previously had it apart and not put it all back together correctly....? You should just need to replace the jet assembly which is easilly removed but you must make sure you get it centred correctly after fitting the new one - it's all in the manual. It takes me about half hour from start to finish but I've done a few. The most difficult bit for a beginner is centering the jet and I would think you should have it all sorted in a couple of hours....

Post by **bmcecosse** » Wed Oct 07, 2009 9:43 pm

Carb comes off easily - just send the wife out to do the shopping - it'll be done by the time she gets home. In any case - these carbs are cheap on ebay if all goes wrong!