Rich_s Posted February 13, 2014 Share Posted February 13, 2014 Cry for help, this car is annoying the hell out of me for past few weeks!few weeks ago it started playing up but only for a few seconds, basically ran like i had lost 2 cyls but cleared and was fine again for a few days, last week it did it and would only run if i left the choke on about 10mm out and could just get to 40mph slowly and no power.i did a comp test and all at 150, rebuilt carbs twice and all was ok, removed new plugs and fitted old ones and fitted old float needles and it started up and ran fine so though i had found the problem, all week fine then today i drove up a big hill no problem, coasted down other side then wouldnt accelerate again, pulled choke out about 3-5mm and it would run fine and accelerate without any problem, but only if i left the choke on.new plugs and float valves installed today and its still doing it, removed air box to check the the pistons move and found when i lift the font one fuel comes out the jet, so seems the fuel level is too high, but how on earth could it do this while driving along and sometimes work and sometimes not ??????????any help appreciated as at the moment i would be happy if i woke up tomorrow to find some bugger had nicked it as really pi$$ing me off.........rich Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted February 13, 2014 Share Posted February 13, 2014 Is it too high on the rear carb or front?Is the bowl over flowing?Fuel pump at the right pressure?Bowl at the correct angle relative to the carb? Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 13, 2014 Author Share Posted February 13, 2014 its the front carb causing the problem, its not overflowing out of the overflow just the main jet.fuel pump is original and never been a problem so presume its ok.bowl is in correct position as well, doing my nut in that it can be fine for 200 miles then play up for 20 and refuse to run properly :(thanksrich Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted February 13, 2014 Share Posted February 13, 2014 You got a fuel filter in the system? Just wondering if it's getting crud in the needle valve. Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 13, 2014 Author Share Posted February 13, 2014 i do, just before fuel pump, whole system was cleaned out last friday as thought it was that the first time. Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted February 13, 2014 Share Posted February 13, 2014 Don't tell me this is the first ever REAL documented case of a leaking float? Quote Link to comment Share on other sites More sharing options...
gfiandy Posted February 13, 2014 Share Posted February 13, 2014 I remember someone mentioning that this symptom could be caused by crud in the tube between the float bowl and the jet. Did you flush the as part of you carb rebuild? They also said that sometimes the seal on that tube at the float bowl could be incorrectly placed and partly block the tube meaning fuel is starved.Andy Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 13, 2014 Author Share Posted February 13, 2014 nope float is fine and empty.yes all tubes and jets blown through and no blockages at all, seems i am getting too much fuel as its overflowing into the carb body and somehow lowering the jet (pulling choke slightly) the level drops and stops flowing out, very weird, and as for why it comes and goes i dont know .the tube into the float bowl has not been taken out since was fitted a few years ago. Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted February 13, 2014 Share Posted February 13, 2014 Has the float got bent? Have you checked it?http://sucarb.co.uk/technical-h-type-carburetter-float-chamberCan't see why it would be intermittent though.... clutching at straws. Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 13, 2014 Author Share Posted February 13, 2014 nope, its got the plastic ones that cant be altered, but the float height gap is more than the book says so if anything the fuel level should be lower than std..... the mind boggles! Quote Link to comment Share on other sites More sharing options...
junkuser Posted February 13, 2014 Share Posted February 13, 2014 It does sound like the float valve is catching intermittently. Quote Link to comment Share on other sites More sharing options...
LouisW Posted February 13, 2014 Share Posted February 13, 2014 Is your fuel pump rebuildable? Id check the filter in that as they sometimes get clogged. Or so I've heard! Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 14, 2014 Author Share Posted February 14, 2014 junkuser wrote:It does sound like the float valve is catching intermittently. this is the only thing i can think of as well, although cant see anything it can catch on.fuel pump does have a filter and was removed and cleaned last weekend in an attempt to fix the problem last time :(thanksrich Quote Link to comment Share on other sites More sharing options...
a turner carbs Posted February 14, 2014 Share Posted February 14, 2014 Fuel out of the main jet is a pressurised float chamber, check that the breather isn't blocked. Quote Link to comment Share on other sites More sharing options...
BrendanD Posted February 14, 2014 Share Posted February 14, 2014 I had this problem in 2012. I went over everything, plugs, jets, floats, needle valves, filters, fuel tank and lines, ignition..... Exactly the same symptoms.Turned out the fuel pump had an intermittent fault. One of the valves was breaking from its mount. It meant that when set the fuel was too low in the bowl, when it worked properly, it overfilled the bowl. This combined with needle after needle that leaked confused the issue. In the end the lest set of needle valves and a new fuel pump (because it had finally failed totally) solved the problem.The problem. A combination of intermittent faults combined with an inability to set the carbs properly. My GT6 had a similar intermittent fault on its 'new' pump. every so often the arm slipped off the cam, so no fuel. A NOS pump solved the problem (thicker arm). Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 14, 2014 Author Share Posted February 14, 2014 a_turner_carbs wrote:Fuel out of the main jet is a pressurised float chamber, check that the breather isn't blocked.didnt even think about that! suppose i presumed the whole was so big it wouldnt block, will take them off over the weekend if the rain holds off and see how it looks.thanksrich Quote Link to comment Share on other sites More sharing options...
junkuser Posted February 14, 2014 Share Posted February 14, 2014 Rich, you mentioned that you have a plastic float and it appears to be set lower than you feel it should be.This could mean that the angle of contact with the needle is pushing the needle sideways resulting in abnormal wear or not approaching the jet correctly.If there is a dimple in the plastic where it contacts the needle, the situation would be aggravated.Not saying this is a likely cause, but you seem to have covered the more likely ones so looking for canaries rather than sparrows. The needle designs vary. The full brass ones and the soft nose ones can develop grooves where they contact the jet. This, combined with the contact angle, could cause the problem.The spring loaded ones can vary due to getting muck in them. I sympathize with your frustrations,Mal. Quote Link to comment Share on other sites More sharing options...
Dannyb Posted February 15, 2014 Share Posted February 15, 2014 932 wrote:nope, its got the plastic ones that cant be altered, but the float height gap is more than the book says so if anything the fuel level should be lower than std..... the mind boggles!With the plastic floats you alter the fuel level by placing extra washers under the valve.If this fails then start looking at what pressure the pumps putting out. If the bypass valve is faulty then it could be too high a pressure. Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 15, 2014 Author Share Posted February 15, 2014 further developments.been out this morning and took the front carb float bowl apart, all seem ok but i cleaned it all up and noticed the flot edges were quite rough so smoothed them up and tried again, still running badly without choke but no overflowing.next i thought i would take out the fuel filter just in case, tried that and all seemed to work and no issues, ha ha i thought.......but no, i had started it up using choke and then took it off and was balancing carbs and couldnt get them right without a really high tickover, then noticed the choke had not shut off completely on the rear carb, as soon as i pushed it in and fixed the problem it ran crap again :(so i then checked fuel levels in bowls and needle length in case one had dropped and all was identical, then looked inside the carbs and saw this: front carb you can clearly see the fuel level and rear carb you cant, so guessing there is something in the jet somewhere stopping fuel coming through..... Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 16, 2014 Author Share Posted February 16, 2014 I think it may now be working..... but i have said this before ;Dtook it apart and there was something blocking the jet, seems to have been a bit of the papertowel type stuff i cleaned them out with so my fault :( put back together, fuel could then bee seen in jet and it ran but not as well as it should and wouldnt without at least a bit of choke, then remembered i have altered the jet heights to the std 2.5 turns out, so i set this back to what it was before i started, 4.5 turns out, and now it runs as it should, so tickover set and carbs balanced and running loads better.so from start to finish it has had new plugs, air filters, fuel filters cleaned out, fuel pipe broke down inside so been replaced, piston dampers topped up, carbs completely rebuilt twice and lots of gunk removed, new float valves as old ones were leaking and one final problem of the thermostat starting to fail and opening at higher temps than it was.have noticed the fan belt needs changing as well, i have a new one to go on but not sure if i dare touch anything else hehehehehehehthanksrich Quote Link to comment Share on other sites More sharing options...
nang Posted February 16, 2014 Share Posted February 16, 2014 4 & 1/2 turns seems to be a hell of a lot. It must be running quite rich.Tony. Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 16, 2014 Author Share Posted February 16, 2014 thats what i would think as well, but not the case, the last mot a few months ago said it was actually running a bit lean!it did seem like the first 2 turns hardly lowered it at all though, also the jet bearing doesnt sit flush with the bridge either like i thought it should do, the bottom pic above shows it sort of.not sure if someone has fitted different needles at some point but the plugs are normally light tan and doing about 40mpg so seems ok, or did before last 2 weeks or pain heheheherich Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted February 16, 2014 Share Posted February 16, 2014 Are we talking about the same thing? Isn't the "standard" starting tune based on turns down FROM the flush position, not the "fully up" position? Quote Link to comment Share on other sites More sharing options...
Rich_s Posted February 16, 2014 Author Share Posted February 16, 2014 thats where i have had a problem on my carbs, the bearing is not flush and when fully screwed in the jet is not flush with the bridge either, so have just had to play around until the plugs are the right colour, which seams about 4.5 turns from fully in and half way between the top of bridge and top of bearing.... Quote Link to comment Share on other sites More sharing options...
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