Isn't your filter.the malpassi 30017FK85V08 with regulator built in? Seeing it half full(half empty) doesn't seem right I'd been looking round that area Good luck
Have you rejetted the carbs.? The webbers dont run well at all with the original jetting . Having confirmed your carbs are rejeted, by which time they will be nice and clean and free of any crap from the tank which would be unlikely with the malpassi, While the carbs are off, if you have those tin gaskets between the carb and inlet, throw them away and fit the phenolic type or at very least the green paper type that are about 2 mm thick, they seem to work much much better. Fit an inline fuel pressure gauge and check the fuel pressure.. 2.5 psi is ample. Throw the mechanical pump away and fit an electric one.. I seem to have got lucky with the Chinese FACET copy, Dont buy a FACET they are Marmite. Te FACET pump was the only thing that let me down on my van so far.. The chinese cube has lasted 18 months and 7000 miles so far.. Delivers 3 psi and is regulated to 2.5 with the Malpassi . Fit POINTS...All that electronic stuff is affected by the heat, Have you felt how hot a VW dizzy gets.. I have points and a condenser in an aftermarket cheap vacuum advance dizzy, and despite the reports of neither being any good and points being unreliable etc .. My van starts first time every time hot or cold.. you just need to adjust them properly and maintain them.. While your at it since you might as well check everything, Adjust the valve clearances.. Thy wont be causing your problem but the van will rum masses better with then adjusted spot on.. Doing all of that at once wont answer what the problem was, If you were real curious to find the cause you would have to eliminate one thing at a time.. If you just wanted it fixed, then spend a day going through it all. You seem to have eliminated the breather issue , with no change , But if its still hissing when you take off the cap then next time you run for gas, dont neck it, and leave the gas cap off... If it still has the same problem then it isnt tank ventilation..
All this but I would argue about the electronic ignition. Never had an issue with it. I have an inline rotary electric fuel pump and my glass bowl on the regular can sometimes have low fuel when ticking over (low voltage I suppose). I have never had a fuel starvation issue. The downside is that you can hear the pump whine when running. The carbs are usually supplied with F78 emulsion tubes. They need to be changed to F6 otherwise you can get a horrible flat spot on acceleration. There is one in each.
Hello folks... I’ve been trying to help Christian figure out what’s wrong with his motor. I’ve witnessed the power loss from the safety of following in my own van when we’ve been going up hills. I can’t help feeling that because the spluttering only starts after a while on a long gentle slope or on hard acceleration when joining a motorway that it’s to do with fueling, or rather lack of it. @SkutterBob - I hadn’t realised the Filter King has an integral pressure regulator. That suggests it should be on the demand/exit side of the fuel pump. Any ideas on how it gets only half full, and what’s occupying the other half - vapour, air, nothing? @redoxide - that’s a great write up! The carbs were rejetted a while back. The van runs fine except as described when it splutters on occasion during prolonged powering. I don’t think it’s a fuel boiling/evaporation problem because it starts up ok from being hot (although the resin spacers are a good idea I’m sure). Measuring the fuel pressure seems the next thing to do....
You are right, it should be on the exit of the pump. I think they are set at factory to be 2.5-3psi do should be ok, but worth checking. My glass bowl fills almost full when driving and then gradually empties on tick over. It did this with mech pump and now with the electric one. It is maybe down to the pumps not working as fast on low revs. Doesn't seem to get lower than a third and never runs out. The symptoms may still be crud in the carbs. I had an fiesta do the same thing. Worked fine, then spluttered then ok again. Crud in a jet that sometimes moved out of the way enough for normal fuel then kept blocking.
If the regulator is on the wrong side of the pump, the pump will be pushing 7psi to the carbs which is too much and they will flood as the fuel is forced past the float needles.
I am going to have to establish the fuel pressure,buy the improved spacers( eurocarb?)and take the carbs off AGAIN! To get them blown through. So frustrating new engine and running lovely otherwise although I still feel I should have a wee bit more torque from the new 1641...
I also discovered that the standard throttle pedal setup was not opening the carbs fully resulting in loss of power. A butties bits throttle kit fixed that.
I wish I could understand how the glass bowl empties! It’s under positive pressure so can’t be a vacuum, so does the regulator let in air somehow? Pretty sure CK has already gone for the Butty’s bits option already CK - I’ve got a pressure gauge we can play with.
A real nice easy way to test for decent fuel pressure from your pump, which may help to eliminate some probs. First make sure motor won’t start and usually I take the rotor arm out because I don’t want a sparking lead in the engine bay, replace cap. Take fuel pipe off from the T piece where it feeds both carbs. Lay the fuel pipe in a large clean and clear plastic bottle , 1.5-2.0 litres, an old water bottle will suffice. Hold the pipe about an inch into the bottle that’s laying on its side. Have your glamorous assistant crank the motor for two or three seconds and watch the vinegar stroke out of your pipe. It should jet out like a fourteen year old home alone. Should hit the bottom of the bottle or there about. If it’s just trickling out then you dont got enough pressure. Ask your fuel pump to think of someone nice then try again. If you are still failing miserably then you have a fuel supply issue. This could be a cream crackered pump, or it could be crud in the tank/filter/pipes/pump. If you is getting a real nice shot, then the fuel supply is good to that point. Ozziedog,,,,,,,,, careful careful careful, don’t want any accidents do we.
Yes Butties bits throttle assembly is fitted. I'll defo get over to Mcswiggs next week. away this weekend. Thank you for all your supportive advise. we will crack it and i will update.
Another thought...can i purchase a screw in malpassi fuel gauge with my model of filter king? Can anyone tell from the pics?
Dunno. You can buy in line facet ones on eBay cheap. It is not advisable to leave them permanently in though.
Looks like that bronze nut by the flow exit in the photo on page 1 is where you’d screw in a malpassi 1/8 inch permanent gauge. Seems like a good idea!
My 1641 with twin carbs took a while to loosen up. I was initially a wee bit disappointed with the "performance" It took a wee bit of messing around to get it to run from the start and I worried that I might have buggered the cam with all the starting and stalling and bad running and messing with carbs.. When it eventually got running it wasnt that slick in the performance stakes , but I was taking it easy and running it in properly .. I feel that only now after a good 5000 miles has it come into its own and runs real good ( I will conceded the failure to start today but that was the starter giving up the ghost) I was having a think about the breather, If you have it looped into the top of the carb it could effectively be sucking air out of th tank and actually creating a vacuum.. ? The correct way would be to put it in the airflow or simply vent it to the atmosphere You wont get fuel out of it since the metal tubes loop away higher than the tank.. If your running a 009 get rid and drop in a vacuum dizzy check your valve clearances and that they were done correctly.. I also had trouble with air leaks at the manifold ballance tube so ali welded the take offs for the hose.. and as mentioned previously, binned the rubbish tin gaskets .. Also its important to balance the carbs properly, dont guess, buy a vacuum gauge t ensure both carbs are pulling the same airflow.. and that the linkage is pulling the carbs open at the same time .. It takes ages to set them up first time but its really important to follow the correct procedure in the proper sequence..
So...getting 3.0psi from the filter king on the gauge and the filter king is defo on the correct side of the pump. Found a fuel leak on the right hand carb. Can be seen on the foam seal in the picture. Had an MOT today and on the diagnostic machine at the garage the readings showed the engine running rich at high revs... Think we will be taking the carbs off and do some investigation...
The leak maybe due to heat soak. When the engine is running, the fuel cools the carbs - that's why they can get condensation on them. When the engine is switched off, heat from the manifolds rises into the carbs and boils the fuel in the float chambers. This also expands the fuel and can cause it to dribble down the outside of the carbs. The fix is to buy the extra thick carb to manifold gaskets. You have strange looking spring brackets too. Have been on the Eurocarb website to see the diagrams?
