Hot starting problem

BigMonkeyMan

BigMonkeyMan

0
Right gang. I need some more help I'm afraid. Jessica has an ongoing problem being difficult to start when hot.

She's had the SU conversion which is much better now I've set up the needle and spring properly, and a leccie fuel pump so plenty of juice, it's just that after a decent run she's impossible to start for an hour or so.

Has anyone got any ideas? Mrs Monkeyman is getting very annoyed with the van and the lack of use, so we're getting to ultimatum time. If I can't get a few reliable miles under my belt in the next few months, she'll be for the chop!

Does anyone know of a commer friendly garage in scotland so I can throw some cash at her to get some use!

thanks for any help

Rupert

"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
Hi Rupert, I know you know your stuff so I'm just stating the obvious probably.....when its hot and wont start, have you actually pulled the fuel line off the carb to see if plenty of fuel is reaching it? ....If your fuel line as original goes across the back of the rad or is touching the engine, it gets incredibly hot....well worth getting a longer pipe and running it right round the front of the engine bay....probably nothing you didn't already know:I:)

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''COMMER'EnSayThat''
 
Colin,
now worries Jessica's future at our home is in jeopardy so any advice is appreciated!

plenty of fuel (I did the pipe removal trick)

the pipe actually runs round the back of the engine as the carb inlet is to the rear of the van. It's also braided pipe

Any other thoughts ?

Rupert


"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
hmm....and the carb? is it new or second hand? does it have any blockages? are the correct jets fitted? .accelerator pump diaphram split? float needle sticking?..don't suppose there are any pin prick water leaks that could be getting the electrics/dizzy/plugs/leads wet? .when the problem is occuring have you tried removing the air filter and covering the intake with the palm of you hand, whilst trying to start up?...erm? I'm out of ideas now, sorry:I

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''COMMER'EnSayThat''
 
If the fuel supply is ok, could it be something electrical breaking down when it is hot, like the condenser?

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'I intend to live forever - so far, so good'
 
Does any part of the pipe go above the inlet to the carb? It could be draining back into the tank when there is some heat around the pipe. SUs are usually good on the starting thing. Have you seperated the inlet and exhaust manifolds? The inlet one can get very hot when stood for a while after a run which will evaporate any fuel trying to get to the cylinders for the first few cranks. I put a heat deflector between them and even when the motor was running super hot it starts first go. Have a check how hot the pipe is actually getting, at the back of the bay it could be hotter than expected. I know my bulkhead gets almost to hot to touch on a long low speed run. I ran the pipe right round the front where the brake pipe goes. It never even gets warm. The needle valve could have a little crud in it allowing air to seep in and the fuel to drain back? Only other thing i can think of is as renaultvation suggests an electrical issue. Is the coil mounted to the top of the motor? I would move it to the inner wing on driver side to keep it cool. Coils dont like the heat at all. Running lean can also cause hard hot starting, plugs should be a nice darkish tan colour. If they are whiteish could be to lean or wrong heat value plugs. Ok i am out of ideas now...!

Well...alright then, maybe just a little...
 
thanks for the help guys.

The set up is hif44 SU carb with K&N filter on a Commer Racer modified manifold setup [separated manifolds]

I'm using the SU abutment plate (?) to mount the cables which includes a bit of a head shield at the bottom.

I used win SU (www.winsu.co.uk) to pick a needle (BCG) and spring (Yellow - strong) and then set it up with the colourtune - could still do with more tweaking (it's pretty difficult to get to the adjuster screw!)

If I pull the fuel pipe off with the ignition on it squirts fuel all over the engine bay (good for toasting marshmallows), so no problem with vapourisation there I don't think.

I'm liking the idea of the coil being too hot. I'll move it next to the brake servo to see if that helps.

cheers

Rupert

"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
quote:
Originally posted by THE ICEMAN

Does any part of the pipe go above the inlet to the carb? It could be draining back into the tank when there is some heat around the pipe.


I'll have a look at that too. I may be able to route the pipe up on the left hand side of the engine.

"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
Tricky one this as all the obvious things have been suggested.
It would be worth having the mixture checked on a gas analyser at a friendly Mot station, much more reliable than a colourtune! It could well be that the carb is running too rich rather than to weak and that would cause non starting when hot as your flooding the engine and starving it of air, its also worth looking at the exhaust tailpipe to see what colour it is, if its sooty then its running too rich.
One other point, electric fuel pumps can push too much fuel through to the carb and even cause the needle valve to stay open when it should be shut. My Bedford CA has a leccy pump fitted and I also fitted an in line pressure valve to keep the the correct 2lb of fuel pressure getting to the carb. That may be worth checking?

Bloody Commer`s!
 
Hi Rupert, I had poor starting when hot with the Beddie and it turned out to be exhaust valve clearances down to zero, thus loosing compression and an amount of power.
Worth checking if you haven't already.
 
As Greg says, check the tappets when hot. And have a good look around for air leaks. What fuel pressure is the pump ?. Don,t normally get hot start problems with SU,s. Also check rotor arm/dizzy cap/condenser.
:)

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"You,re only supposed to blow the bloody SLIDING doors off"
 
True, and you need someone to cook and clean for you when your camping. ;)quote:
Originally posted by Dodgemark

how could you think such a thing alan[}:)] whos going to push start it otherwise:I:D

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1980 perkins diesel spacevan



Bloody Commer`s!
 
thanks for all the help. Mrs Monkeyman has long since given up on the van so I do the washing up and cooking anyway :(

I did a bit of work on her yesterday as per the advice. I've not had a chance to do a proper run out yet, but I have had her standing on the drive ticking over for quite a while, stopping and re-starting and she seemed ok.

Yesterdays jobs were - set the tappets, tidy up the fuel lines, set and clean the plugs. The plugs were quite dark (so too rich - she's been running a bit on the drive so I'll have another look after a good run out)

I'll keep and eye on the mixture, she's got electric points so no condenser. I'm going to keep a spare coil just in case she gives up again, I can swap them over to see if the spare (cold) one makes a difference.

Oh and Colin, the carb is a fully reconditioned one from Ebay so should be in good nick. Saying that I was sat in my garage for a couple of years gathering dust!

Rupert

"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
Well today was the big day - time for lots of testing!

I was up early and took Jessica off for a spin this morning. The plan was to get her really hot and then stop and see what happens.

Firstly a few county lanes. The choke came off really early and she was up to temperature quite quickly. the lanes were great. Loads of power. Then onto the dual carriageway for 2 or three laps round the test track (two roundabouts with dual carriageway in between) She actually got up to 70 at one point! She was going really really well. The noise is fantastic. So off to tesco to check the hot starting problem.

I went to the bottle bank to check the "quick restart" problem. Completely fine. Then off into tesco for breccie. Out (after about 20 minutes) and she started fine.

so off to the petrol station... and finally a problem. The carb isn't quite tuned properly yet and there's a slight hesitation when pulling off so I stalled and it was a bit of a pain to start. (lots of cranking with nothing happening) so I swapped over the coil as a test and vroom! All fine again. Other (hot) coil on again and back to lots of cranking. So there's a problem identified!
Over the next few days I'm going to move the coil to the inner wing to see if that helps, and also have a look at the clutch and monster oil leak (I think I just need a new rocker cover gasket)

thanks again for all your help everyone - I'm getting closer to having a usable van!

Rupert


"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
quote:
Originally posted by Panky

Oil in the dashpot?

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How refreshing



lots I think - I've been using motorbike engine oil (as it was in the can!)

"Not tonight love - I'm varnishing me roofrack"
www.littleyellowcar.co.uk
 
Thank goodness for that, well done that man for your perseverence:D
Give the mixture screw a 1/4 turn out and see how she goes. The last time I took the Mini for the MOT the guy was having trouble with the emissions, in the end he dropped the needle ever so slightly and that sorted it:)
Moving the coil to the inner wing is definitely a good idea.

th_IMAG0033.jpg

How refreshing
 
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