Cuts metal like mad Posted August 22, 2009 Report Share Posted August 22, 2009 the last hitachi I rebuilt... I made my own gaskets, and never had a problem with it. :D Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 ok got all the leaks stopped, i made a rookie mistake and istalled the wrong gasket instead of matching up my old gasket, ok now i took the carb off and double checked everything, still idles at 2500 with the choke off, adjusted the needle and the idle screw, still idles high, when you turn the engine off should the float chamber drain? it does Quote Link to comment
datzenmike Posted August 22, 2009 Report Share Posted August 22, 2009 No. How fast? Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 i am beginning to think that the float is overflowing, when i turn the motor off, the float bolw looks full, sometimes its on the dot then sometimes its full, if the bowl is overflowing could that cause the erratic idle at 2500? Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 ok this is confirmed, the float is overflowing, it fills up then over flows, when i turned the engine off it was completely full, i let it sit, came back and its on the dot Quote Link to comment
datzenmike Posted August 22, 2009 Report Share Posted August 22, 2009 Over filling the carb would not cause it to rev higher. See the round (ish) thing with the 7 screws holding it on and a small copper pipe sticking out towards you? In the center there is an adjustment screw (it may have a rubber plug over it) Turn the screw counter clockwise a few turns (keep track of how many) Rev a few times and the idle may come back down. You could also try leaving the hose off the copper pipe but plug the hose up. Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 ok adjusted the float down and now my flota level is good but the truck wont idle at all and when you give it gas it pukes and backfires and will rev up high and then quit, adjusted both idle screws in and out and in and out and adjusted the screw datzenmike was talking about, tried everything i could think of Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 ok now i ahve the carb off again, studying checking,, studying some more, cant figure it out, it all seems good, one thing i dodnt mention is my throttle cable is loose now that i put the carb back on the truck, when i took it off it was tight, i tried to see if i assembled the linkage wrong, but i cant get it to move back anymore so that it will tighten up the cable ? im so frustrated guys please give me some info or stuff to try Quote Link to comment
Buzzbomb Posted August 22, 2009 Report Share Posted August 22, 2009 ok now i ahve the carb off again, studying checking,, studying some more, cant figure it out, it all seems good, one thing i dodnt mention is my throttle cable is loose now that i put the carb back on the truck, when i took it off it was tight, i tried to see if i assembled the linkage wrong, but i cant get it to move back anymore so that it will tighten up the cable? im so frustrated guys please give me some info or stuff to try Did you putting the throttle return spring back on the intake bracket? I can't see it in the pics. If not, maybe your throttle cable is getting hung up. This is the first thing I'd check. If it was me, when I had the carb off, I'd turn the idle speed screw OUT until it doesn't contact the linkage. Then, I'd turn it IN about two or three turns to start to give yourself some reference point to start with. It seems like you are just turning things, changing this, moving that without any baseline settings. Give yourself some starting points, and follow each until you know it's right, then move on to the other- process of elimination. Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 hey buzzbomb stay online and i will take a pic real quick of the linkage setup Quote Link to comment
MAG58 Posted August 22, 2009 Report Share Posted August 22, 2009 I said it was the anti-diesiling valve because in mine, the little electo-magnet failed and the engine would not run on the low speed circuit (because it was cut off), so after I just removed it, it ran fine. Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 I QUIT!!!!!!!!!!!!!!!! fuck it, japanese piece of shit, if fucked with everything that could possibly be fucked with, and not shit, starts up and revs to 4500 and stays there, the damn primary isnt even OPEN NOR IS THE SECONDARY!!!!!!!!!!!!! someone please give me 350 bucks so i can rebuild my mikunis!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 ok so when you start the truck cold with the choke on it revs to 4500 rpm, then when its warmed up and the choke is off it drops to 2500rpm??? i just cant figure it out, its got to be right in front of my face, the float level is good, all the gaskets are sealing, the linkage isnt stuck, the choke works, the idle adjustment screws have zero effect, im stumped, i completely disassembled the carb last night and layed out all the parts in order, i put them all back in order as well, i replaced the little metal balls, all the seals, removed and cleaned all the jets, and i blew out all of the passages with 100 psi of air, everything is tightened, and in place, what do you guys could think is wrong with it? what is your opinion? Quote Link to comment
Braden Posted August 22, 2009 Author Report Share Posted August 22, 2009 I said it was the anti-diesiling valve because in mine, the little electo-magnet failed and the engine would not run on the low speed circuit (because it was cut off), so after I just removed it, it ran fine. removed it and it ran even worse Quote Link to comment
Buzzbomb Posted August 22, 2009 Report Share Posted August 22, 2009 the idle adjustment screws have zero effect, im stumped, i completely disassembled the carb last night and layed out all the parts in order, i put them all back in order as well, i replaced the little metal balls, all the seals, removed and cleaned all the jets, and i blew out all of the passages with 100 psi of air, everything is tightened, and in place, what do you guys could think is wrong with it? what is your opinion? The reason why the idle mixture screws don't work is that you're idling at 2500 RPM. You are running on the primary circuit of the carb and it is drowning out the idle circuit. 100 psi seems like an awful lot of pressure to be putting through carb passages, IMHO. If the float is ok, and you are sure the carb is on tight enough, secondary fully closed, your cable isn't dragging, and you have a hooked up throttle spring, you really should start off with teh basics. I still think you should back off teh idle speed screw until it is just off the linkage, then set it at 2 turns in from initial contact with the linkage. Seat teh mixture screws LIGHTLY, then back them off 1.5 turns. This works with all carbs to give you some sort of starting point, and I don't see why a Hitachi would be any different. Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 the idle srews dont do jack, the one screw is not even touching the linkage which means it isnt opening up the butterfly at all, its not even touching the linkage, the needle screw i set to specs in the rebuild kit, i turned it in then backed it off 2 to 2.5 turns and every increment inbetween. i guess i am confused, if both the butterflys are closed then why is the truck revving so high? its shouldnt run at all right? if all of my linkage is correct and everything else is correct, what else could it be just some combo if idle screws beinmg out of adjustment? has anyone ever heard of this problem before? i have 44mm mikunis damn i wish i had the money to rebuild them. Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 i would really appreciate some fast responses guys i really need your help, sorry if that is too much to ask but i need some transportation, please please point me in a direction, thanks Quote Link to comment
Buzzbomb Posted August 23, 2009 Report Share Posted August 23, 2009 (edited) Since your idle is so high, you aren't anywhere near the idle circuit, and the truck is running on the main circuit +. You need to figure out where it is getting excess gas from other than the idle speed since it is idling way high with the butterflies fully closed. Theoretically, if the butterflies are fully closed off, and you are pulling fuel from the boosters, the truck should be totally flooded out with visible gas piling up in the throats. So..are your butterflies REALLY closed? If so, where is all the gas dumping in from the main circuit going and how is getting there in the first place? It has to go somewhere, so how is all that excess gas even being burned? If you were driving down the road at 2500 RPM, I guarantee the throttle blades would be more than cracked open to USE the gas coming from the main circuit. That in itself is the reason the fast idle cam cracks open the throttle blades. When you are getting that much gas, you need more air to burn it. I'm not a Hitachi carb expert, but a carb is a carb when it comes to basic functioning. Flooding usually means too high float level, or needle being blown off the seat somehow. I'd set the mixture screw to 2.5 turns and leave it alone. You will NOT get any response from it when you are idling at 2500. Fine tuning the mixture screw is a moot point. Edited August 23, 2009 by Buzzbomb Quote Link to comment
datzenmike Posted August 23, 2009 Report Share Posted August 23, 2009 To rev to 4,500 a lot of air must be getting in. It also must be going through the carb in order to pull gas in with it to run and not just be an air leak from a gasket. Remove the throttle cable and make sure the primary barrel is fully closed with the idle speed screw backed off and not holding it open. In this picture the adjusting screw on the right is the mixture screw. The one on the left just behind the linkage is the idle speed screw. Be sure the idle speed screw is backed out and not touching the throttle and holding it open. Try pulling on the throttle in the opposite direction the cable pulls from if it was on. Does it move? When you had the carb off did you look at the secondary barrel? Was it fully closed?? Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 (edited) yes the secondary was fully closed, and the screw you are talking about i backed it out so that it was not touching the linkage at all, thus keeping the primary shut, i even took the screw completely out once to be sure that it wasnt interfering with the primary in any way, i also adjusted the screw every time i had the carb off so that it barely cracked the primary open in order to promote idle. when the engine is off i look down the primary it is closed as well as the secondary, the primary must be opening up when i start it up and it must be opening completely, but how, im not touching the gas pedal, and there is a hefty spring holdin it closed unless i throttle up, and no it doesnt move in the opposite direction at all, how could it? the throttle blade wont let it move backwards Edited August 23, 2009 by ghettobraden Quote Link to comment
datzenmike Posted August 23, 2009 Report Share Posted August 23, 2009 ... and no it doesnt move in the opposite direction at all, how could it? the throttle blade wont let it move backwards This is an odd problem so don't misunderstand if I ask strange questions. NEVER ASSUME. I have to be sure that it was closed. OK if the primary and secondary are closed tight then there is only one other way for gas and air to get into the intake manifold. The BCDD. It's job is to add gas and air on deceleration then the intake vacuum exceeds a per set limit. It's to prevent emissions. If this is stuck open or the preset is set too low it will stay on and may cause a high idle. 1/ Remove the hose going to it and try it. Without the vacuum signal it should stay off. 2/ Try turning the adjustment screw all the way out to raise the vacuum level needed to trigger it. 3/ There is a hex shaped solenoid with a white wire on it, on the right side of the BCDD. Try applying 12 volts to it. This solenoid, when energized, will bleed of the vacuum signal and shut the BCDD off. Good luck. Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 (edited) the whole time i have been trying to tune it the vacumm hose has either been off or plugged i tried both, i tried turning the screw in and out to no effect, and please please ask strange questions, if they are strange most likely i havent tried it, i took the bcdd apart and cleaned it and put it back together, maybe i should take it apart and oil the little metal round plunger, i replaced the gasket on it when i had it apart, maybe the gasket could be blocking a passage? ill take it off and look This is an odd problem so don't misunderstand if I ask strange questions. NEVER ASSUME. I have to be sure that it was closed. OK if the primary and secondary are closed tight then there is only one other way for gas and air to get into the intake manifold. The BCDD. It's job is to add gas and air on deceleration then the intake vacuum exceeds a per set limit. It's to prevent emissions. If this is stuck open or the preset is set too low it will stay on and may cause a high idle. 1/ Remove the hose going to it and try it. Without the vacuum signal it should stay off. 2/ Try turning the adjustment screw all the way out to raise the vacuum level needed to trigger it. 3/ There is a hex shaped solenoid with a white wire on it, on the right side of the BCDD. Try applying 12 volts to it. This solenoid, when energized, will bleed of the vacuum signal and shut the BCDD off. Good luck. Edited August 23, 2009 by ghettobraden Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 ok i took it apart and cleaned it again and used a small piece of wire and poked through the passages and blew through them to verify they are clear, tomorrow i will re install it and try again but i have got the feeling that wont help, lets say it doesnt where do i go next? its all clean and seems to be in goood working order Quote Link to comment
izzo Posted August 23, 2009 Report Share Posted August 23, 2009 get a weber, install, done. Quote Link to comment
Braden Posted August 23, 2009 Author Report Share Posted August 23, 2009 get a weber, install, done. i have 3 dollars cash and 20 dollars in change, try a suggestion that doesnt require the use of money, lol, im probably the poorest guy on the forum Quote Link to comment
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