PYU940F Posted May 18, 2018 Report Share Posted May 18, 2018 Hi For many years have had no.2 plug foul on start up but only if I use choke. If warm day and start with no choke then no fouling. When I pull plug it is difficult to say but looks more fuel then oil but probably a bit of both. Mixture on no 1 cylinder looks good to weakish from plug colour. Carbs are new and compression OK so am guessing a worn valve guide, but why only with choke? Anyone else had a similar problem? The head s not modified for unleaded but the car only does a very low mileage so do not suspect seats. Cheers Simon Quote Link to post Share on other sites
Lebro Posted May 18, 2018 Report Share Posted May 18, 2018 I have similar but on pot No.4 Cleaning (sandblasting) the plug fixes it for a couple of months, then it fouls again. Plugs are NGK BP6 type I have just got hold of some BP5's to try as they will run a little hotter, & may burn off any fouling. we will see Bob. Quote Link to post Share on other sites
RogerH Posted May 18, 2018 Report Share Posted May 18, 2018 Hi Simon, it could be a worn #2 valve guide but as it only happens on start up there should be very little oil getting down the guide with the engine not running. Have you checked/replaced #2 HT lead + cap. Have you tried turning the engine over with NO choke for half a dozen rev's to warm the plug and then apply choke. Have you tried pulling the choke out 1/2 way. Bob, I don;t think a hotter plug will improve the problem as it is on;y on start up with choke. Roger Quote Link to post Share on other sites
Rem18 Posted May 18, 2018 Report Share Posted May 18, 2018 Did I miss car not being specified? Is this the 4 or the VW camper? Quote Link to post Share on other sites
PYU940F Posted May 18, 2018 Author Report Share Posted May 18, 2018 It is the 4a. Starts OK with no choke and fires on all 4, but as soon as use choke on starting only fires on 3 and will not clear even if I drive away and try and clear it with an Italian service. Redid compressions today and they are not brilliant. 118/135/125/120. Strangely No. 2 the highest. That is with a Clark screw in tester, throttle wide open. Did not have a suitable syringe for a wet test. (will borrow Caroline's cooking one later when she has gone out). The bottom end was rebuilt in the 80's (piston/liners/bearings etc) and the oil pressure is by the book but the top end was not touched. Planning to do the lead free seat conversion so I reckon if I do guides and valves as well all will be well. Simon Quote Link to post Share on other sites
Peter Cobbold Posted May 18, 2018 Report Share Posted May 18, 2018 (edited) Check the fuel level in the jet is not flush with the bridge. Engien slope will let liquid fuel slop into #2 rather than 1. Edited May 18, 2018 by Peter Cobbold Quote Link to post Share on other sites
PYU940F Posted May 18, 2018 Author Report Share Posted May 18, 2018 Thanks Peter, will do that. My garage is on a bit of a slope nose down when I back in. I will go in the other way and see if it makes a difference. If fuel level is too high in the jet, how is it adjusted down? New carbs do not forget. I suspected my compression tester was lying, and borrowed another today. 170/170/170/165. Talk bout the wheel taper's syndrome! Simon Quote Link to post Share on other sites
Peter Cobbold Posted May 18, 2018 Report Share Posted May 18, 2018 Thanks Peter, will do that. My garage is on a bit of a slope nose down when I back in. I will go in the other way and see if it makes a difference. If fuel level is too high in the jet, how is it adjusted down? New carbs do not forget. I suspected my compression tester was lying, and borrowed another today. 170/170/170/165. Talk bout the wheel taper's syndrome! Simon Hi Simon, The fuel level in SUs is adjusted in the float chamber, There's a lever lifted by the float that closes off the valve. It should have been set by the supplier ! But if the misfire happens when the car is nose down its probably a red herring. There are lots of rubbish plugs around....Champion are now Chinese. Peter Quote Link to post Share on other sites
PYU940F Posted May 18, 2018 Author Report Share Posted May 18, 2018 Rubbish plugs? Strange, I fitted a new set around 1000 miles ago and the problem went away, Great I thought. Came back about 300 miles ago. What are the recommended plugs that aren't rubbish? S Quote Link to post Share on other sites
Peter Cobbold Posted May 18, 2018 Report Share Posted May 18, 2018 Rubbish plugs? Strange, I fitted a new set around 1000 miles ago and the problem went away, Great I thought. Came back about 300 miles ago. What are the recommended plugs that aren't rubbish? S Japanese - see Bob Le Brocq above. Quote Link to post Share on other sites
graeme Posted May 18, 2018 Report Share Posted May 18, 2018 (edited) Simon, I always use NGK plugs, NGK BP6HS or alternatively Bosch WR7BC from a known good source. I wouldn't fit Champion if they were free, not the quality they once were. Cheers Graeme Edited May 18, 2018 by graeme Quote Link to post Share on other sites
stuart Posted May 18, 2018 Report Share Posted May 18, 2018 (edited) Nippon Denso are also a good make, be careful where you buy NGK plugs from as there are some hookey copies floating around on likes of Ebay that are rubbish. Stuart. Edited May 18, 2018 by stuart Quote Link to post Share on other sites
PYU940F Posted May 18, 2018 Author Report Share Posted May 18, 2018 I will check what are fitted Quote Link to post Share on other sites
RUBY131 Posted May 18, 2018 Report Share Posted May 18, 2018 I have exactly the same problem on No3 cylinder on my 3a, so I turn over without choke and it takes a bit longer but fires up O.K. and then if it needs choke it gets it. (For reference I do have the high power starter fitted so it turns over quite quickly) Cheers Chris. Quote Link to post Share on other sites
Nick Jones Posted May 18, 2018 Report Share Posted May 18, 2018 Have the plug cap and leads been the same throughout? Might want to try changing those (or at least swap the lead with another and see if the problem moves). Try something (anything) other than NGKs. I've found they really can't stand fuel wetting. Bosch or Denso are both excellent. I personally favour the triple or quad electrode ones - others differ..... Nick Quote Link to post Share on other sites
RUBY131 Posted May 18, 2018 Report Share Posted May 18, 2018 Yes copy that Nick, they are NGK plugs. All the leads caps ect are new but no reason why one should not be faulty. I will give that a try. Thing is once its fired up and running it does not miss a beat and I have even had it on a rolling road under test and no problems. Thinking the worst I imagined maybe moisture from head gasket or even worse liner but not gone that far yet. Cheers Chris. Quote Link to post Share on other sites
PYU940F Posted May 19, 2018 Author Report Share Posted May 19, 2018 The way I start the 4a is identical to Chris. Crank her with no choke until she runs and then choke if necessary. that way the plug will not foul. Crank with choke no good, If have got NGK BP6 so unless they are Chinese clones these should be good. Quote Link to post Share on other sites
Rem18 Posted May 19, 2018 Report Share Posted May 19, 2018 Since I changed the metering unit over to a leaner one on my 5 I was starting with no choke or putting it back in as soon as she fired. Now I think I will be trying your method as I prefer to crank her a bit first to get some oil pressure up first. Quote Link to post Share on other sites
RUBY131 Posted May 21, 2018 Report Share Posted May 21, 2018 +1 to that Rem , it does help get the oil roun especially if you dont use the car that often. Chris Quote Link to post Share on other sites
Rem18 Posted May 21, 2018 Report Share Posted May 21, 2018 Chris I have always done that, but now with the leaner metering unit she needs choke for a minute or two so even more of a reason. Just trying to figure out best way to start her now as seem she needs a bit of turnover from hot. But have always been careful at first as even with non return valve oil filters and an oil cooler you will always see the dreaded green light for a moment (seems like an eternity hahaha) when starting. Will try starting without chock and just accelerator and see, today or tomorrow, I live in a warm climate so it may be different to the UK anyway. T Quote Link to post Share on other sites
peejay4A Posted May 21, 2018 Report Share Posted May 21, 2018 Do you have stainless braided injector hoses by any chance? Quote Link to post Share on other sites
Rem18 Posted May 21, 2018 Report Share Posted May 21, 2018 Tried today....naaah didnt work she wont start without choke since leaner MU. In fact she is harder to start, will have to do some investigation as I replaced Bosch pump with another couple of weeks ago, maybe something aint right, but she was going ok up to now. Good question regards the braided hoses I had thought too, you know there is a lot of trouble now with degrading rubber hoses too. Chris I have always done that, but now with the leaner metering unit she needs choke for a minute or two so even more of a reason. Just trying to figure out best way to start her now as seem she needs a bit of turnover from hot. But have always been careful at first as even with non return valve oil filters and an oil cooler you will always see the dreaded green light for a moment (seems like an eternity hahaha) when starting. Will try starting without chock and just accelerator and see, today or tomorrow, I live in a warm climate so it may be different to the UK anyway. T Quote Link to post Share on other sites
peejay4A Posted May 21, 2018 Report Share Posted May 21, 2018 (edited) Are yours braided? Some of them are prone to vapour lock when restarting a hot engine. Injector hoses Im talking about, not the others. The SS braided injector hoses are nylon inside like the standard ones but some can cause vapour lock, possibly because they are narrower bore than standard. Edited May 21, 2018 by peejay4A Quote Link to post Share on other sites
Rem18 Posted May 22, 2018 Report Share Posted May 22, 2018 Good to know that the braided injector pipes are nylon and not rubber inside or that would mean trouble with petrol nowadays. Quote Link to post Share on other sites
peejay4A Posted May 22, 2018 Report Share Posted May 22, 2018 Yes, but do you have braided injector pipes? Quote Link to post Share on other sites
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