April 4, 201511 yr Sounds like you are referring to the accelerator pump. If it were not working, pretty much any increase in opening of the throttle would cause temporary fuel starvation.
April 4, 201510 yr Don`t be looking down the carb directly w/the engine running like in the video. You are liable to get a BACKFIRE in the FACE. Use a mirror if you need to. You can check the accelerator pump w/the engine stopped.
April 4, 201510 yr I was going to mention something about this earlier, but decided to give you the benefit of the doubt. Did you replace the ball at the base of the accelerator pump when you rebuilt the carb?
April 5, 201510 yr That is the thing in your video, that thing that goes across the throttle and has the jet, I had mine not perfectly aligned when I put the carb back together on my mitsubishi cordia, It sits in a slot on either side of the carb, if its not perfectly seated you will not get the fuel coming out when the venturi effect kicks in. I had the exact performance issues you did after rebuilding my carb. Just take off the top and make sure those things are sitting right. May also want to blow some compressed air to make sure nothing is blocking the passage.
April 5, 201510 yr Author I was going to mention something about this earlier, but decided to give you the benefit of the doubt. Did you replace the ball at the base of the accelerator pump when you rebuilt the carb? Yeah I did replace the ball. Capmarvouls, I think I know what your talking about and will check it. Naru, thanks for thinking of my safety and pointing that out, I will be more careful next time. DaveT, yes that is exactly what I am talking about. thanks for giving my forgetful brain the correct term. All you guys have been super helpful, I think with the help of my local Subie Nut I should be able to figure it out. I'll keep you posted.
April 5, 201510 yr Don`t be looking down the carb directly w/the engine running like in the video. You are liable to get a BACKFIRE in the FACE. Use a mirror if you need to. You can check the accelerator pump w/the engine stopped. that backfire, accompanied with orange flame throwing ability is so much funneir viewed from a coupla feet away than it is to the victim I used to work with a bearded mechanic who was crouching at the rear of a Porsche engine baja bug trying to sort out a miss, The sde draught nearly burnt his beard off. I was fortunate to witness it
April 5, 201510 yr Author I FIXED IT!!! My friend (not the suby nut, but a fellow budding mechanic) and I were poking around the carb today, adjusting the float so it runs richer, and stretching the spring that the accelerator sits on. We get in the car, expecting it to start jerking and die, when all of the sudden, it takes right off without throttling it at all!! we get on the highway, still no jerking at 1/4 throttle! (normally it would have been like a bucking-bronco at 1/4 throttle) Then the ultimate test: we got on to a dirt road, slapped it in 4X4 (it would always do it fiercely in 4WD) and put it in 1st gear (again, when it was guaranteed to kick like a mule) ABSOLUTELY NO BUCKING, JERKING, OR MALFUNCTIONING OF ANY KIND!! I am so happy!!
April 6, 201510 yr good. But, wait until next few starts and drives for confirmation is my approach after meeting Murphy a few times. I gotta ask why you think you richen a mixture up by adjusting float level ? Did you find float level was higher or lower than the dot in the window ?
April 6, 201510 yr Hey Jono I have a funny story about those side draughts on the VW. I had a 71 VW bus and I was cruising at night to Santa Barbara to go surfing with a buddy of mine. We were still in the process of getting an interior for it from junk yards so there were some screw holes that led to the engine compartment from the interior. As we are cruising my buddy says hey you left the light on in the engine compartment, I can see a light through those screw holes. I was like there is no light bulb in the engine compartment to begin with. Stopped the bus right away and went to the back and the engine compartment was in flames, a quart of oil I had on the sides of the engine bay where the air tunnels are had fallen into the engine and come into contact with those side draughts that are part of the exhaust manifold. Fire was dripping from the engine compartment to the asphalt, I guess it was the burning plastic but it sure did look like the oil was burning also. Thankfully I followed the advice of VW veterans and carried a fire extinguisher in the car. Luckily the flames had not burned the fuel line. Fire was put out and we were able to continue on our way and had a great trip. I keep on thinking what would of happened had my friend not noticed the flicker in the back through those screw holes. Had that bus for a few more years, even drove it 2000 miles to Cabo San Lucas and back along Hwy 1 in Baja California. Great car, had to sell it eventually, but it served me well for a good 7 years. Edited April 6, 201510 yr by capmarvelous
April 6, 201510 yr :D a nice story - had my own engine bay fire story - sneaking degreaser on my engine bay in prep to go to the carwash across the road that did not allow use own degreaser (theirs weaker than dishwater) the running engine engine pipes ignited things - i panicked and just drove, bonnet up, peering between it and bottom of windscreen - blew it out That Baja bug had a side draught positioned to actually be a back draught - un filtered trumpets blasting right backwards .....
April 6, 201510 yr Author good. But, wait until next few starts and drives for confirmation is my approach after meeting Murphy a few times. I gotta ask why you think you richen a mixture up by adjusting float level ? Did you find float level was higher or lower than the dot in the window ? I feel ya on the murphys law. And "richen" was the wrong word to use on my part. I was too excited to think of a better word. Lower than the dot.
April 6, 201510 yr Raising the float level DOES richen the mixture. The same amount of venturi vacuum draws more fuel.
April 6, 201510 yr Raising the float level DOES richen the mixture. The same amount of venturi vacuum draws more fuel. not in my school of thought...unless the higher fluid level increases the fuel pressure out the jets ???? sometimes 2 plus 2 does equal 5
April 6, 201510 yr Author "sometimes 2 plus 2 does equal 5" You guys must have a pretty crazy math system in Australia, Jono... lol
April 7, 201510 yr ... You guys must have a pretty crazy math system in Australia ... Not only in Australia, See: https://www.youtube.com/watch?v=F6hTrzw3EJM Edited April 7, 201510 yr by Loyale 2.7 Turbo
April 7, 201510 yr not in my school of thought...unless the higher fluid level increases the fuel pressure out the jets ???? sometimes 2 plus 2 does equal 5 The higher the fuel is the less of a hill it has to climb to exit the discharge. Like the difference between a short straw on a full milkshake and a long one pulling from the bottom. It takes less pressure difference between the venturi and the bowl to push the same amount of fuel when the float level is higher. Not to mention,the air holes in the emulsion tubes will be submerged more deeply. That is why the float level is so important
April 8, 201510 yr it is a bloody long time since I played with a Holley or Hitachi carb...but aren't the jets and acc pump supply holes at the bottom of the float bowl? I guess they are only part of the fuel delivery of the carbs, so, you open my eyes !
April 8, 201510 yr Not only in Australia, See: https://www.youtube.com/watch?v=F6hTrzw3EJM Dude ! Jeszek ! Was only just watching that white block of chocolate trick on you tube over Easter. Think they also did the seven Mentos in Diet Coke trick, rubber bands around the girth of a water melon to make it implode on first cut ....very small world
April 8, 201510 yr "sometimes 2 plus 2 does equal 5" You guys must have a pretty crazy math system in Australia, Jono... lol actually, I was quoting from a translation from a Mediterranean proverb
April 8, 201510 yr Raising the float level DOES richen the mixture. The same amount of venturi vacuum draws more fuel. Well, only if it was below minimum and "starving" to begin with. Once the level is in correct range, adjusting the float bowl level higher will do nothing until it's way too high, then it "riches". But not in a mixed way. Just dumps fuel past the air bleeds into the horns unmixed. This is flooded not rich mixture.
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