jk4138 Posted November 13, 2006 Share Posted November 13, 2006 Well this weekend I finally got around to replace my Hitachi Carb on my 87 GL Wagon with a newly rebuilt one from carbsonly.com. Everything seemed to go really smoothly pulling the old one out and putting the new one in. The longest thing was marking all of the hoses as to ensure that everything was connected correctly. After getting it back in I went to fire it up after engaging the choke and it fired right up after a few cranks. It went right up to about 2600 rpms which seemed a little high but I figured that could be adjusted at a later time. After getting the idle adjusted to about 900 rpms it seemed to idle a little rough but I figured that could be adjusted as well. Well I drove home from my uncles shop where I was doing the work and it seemed to run fine. Well this morning it was about 40 degrees and I went to start it up after engaging the choke once again. Well it did not fire up right away and took me about just as long as it had before I replaced the carb. I have 12V at the choke so I am honestly not sure what is going on. It seems like it is still a choke issue but don't know how that could be. Is there anything else that could be causing me issues starting it first thing in the morning when it is cold? I am really beginning to get frustrated and want to get this problem solved. Any help would be much appreciated. Thanks a lot. Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 Note: I also replaced the fuel filter the week before this so it couldn't be that. Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 Any words of advice would be awesome guys. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 13, 2006 Share Posted November 13, 2006 I feel for your trouble..my friend just recently put on a new carb and we had to adjusted the choke to close it a little tighter for the cold weather start-ups (one notch over)and now it starts the way it is suppose to... and also his float had to be re-adjusted...maybe the float was changed slightly during the shipping or the rebuilder went by the book specs which doesn't always work because of the slight differences in the carb castings..fortunately we had his old carb for a reference to set the float up...the only problem remaining is when coming off the highway, the RPM's drop momentarily to near stall...this could be related to the lower compression values of 130psi ....and since the carb has been remanuf to new engine specs of 165-170 psi..thus the old engine is not pulling enough vacuum to draw the fuel out of the jet when sudden changes of vacuum occur..not sure on this, but time will tell...in the future he is going with the FI conversion Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 It is just wierd because the choke engaged intially but didn't seem to this morning. What would cause this to happen? I need to pull the cover on the air filter housing and see if the choke plate is closing just to make sure but it doesn't even seem to be engaging. I imagine that the rough idle is due to the float adjustment being off some from the change in vaccum which I have no idea how to adjust. Does anyone happen to know of anyone who could take a look at my carb and adjust it for some cash obviously? I just don't have the experience and don't want to take it into a shop because they will charge an arm and a leg just to fine tune it. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 13, 2006 Share Posted November 13, 2006 At 40 degrees it's probably not the choke that's causing your problem. As long as the plate is closed and has a little spring to it when you push in on it the engine should start. You said it has a rough idle - possibly a vacuum leak or idle mixture adjustment.... spray around with some carb cleaner and see if the idle changes - that will locate vacuum leaks for you. How's your ignition system? Cap, rotor, wires, plugs? Rough idle and hard starting can be related to a weak spark too. I hate to say it, but the Hitachi carbs are terrible. They aren't worth the metal they are cast of, they are especially difficult to rebuild, and besides all that they are gutless. I have the patience for most anything that's worth doing right, and I've rebuilt more Hitachi's than I care to remember. I tossed them all in a dumpster one fine day, and I now have one with SPFI and two with Weber's - all of them originally had Hitachi's. The Weber is simple, rugged, and a LOT more powerful than the Hitachi. My sugestion to you is to sell that Hitachi (ebay, here in the for sale forum, etc), and get a used Weber and a rebuild kit. I can rebuild a Weber in about 1 hour and have it running better than a new Hitachi. Last one I did for my sedan cost $190 total - that's including a used carb ($80), two new jets, brand new electric choke, complete redline rebuild kit, and the adaptor plate. GD Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 GD- I will check if it I have a vaccum leak but would that effect the starting only in the morning or just the rough idle. Also how do I go about adjusting the idle mixture? I am leaning more towards this as being the cause for my rough idle. As it is not idling too poorly just causing the car to shake slightly. As far as the choke engaging before and not this morning what would be the cause of this? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 13, 2006 Share Posted November 13, 2006 GD- I will check if it I have a vaccum leak but would that effect the starting only in the morning or just the rough idle. Also how do I go about adjusting the idle mixture? I am leaning more towards this as being the cause for my rough idle. As it is not idling too poorly just causing the car to shake slightly. Sadly, on the Hitachi the idle mixture is usually "pinned" so you can't change it. Some rebuilders may leave the pin out - especially if they think you are going to need to change it. The adjustment is on the bottom of the front of the carb. Burried behind the power steering pump where you won't be able to get to it. :-\ They aren't supposed to be adjusted, so there isn't a provision for getting to it really. If the car is shaking like that, it's a pretty good indication of a vacuum leak or a really badly adusted idle mixture. (or ignition). As far as the choke engaging before and not this morning what would be the cause of this? Did you look down into the carb and see the plate wide open or something? You did pump the gas a few times right? I would imagine that it IS working.... I can't imagine the rebuilder would have adjusted it in such a way that the car wouldn't start in 40 degree weather. That just doesn't seem possible unless they are totally inept. The choke isn't adjustable anyway - it's held in place with a brass pin and rivets - it's not designed to be moved. GD Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 GD- I just went out to start it and checked to see if the choke plate was closed or not after pumping the gas a few times. The plate was still completely vertical. Either carbsonly.com sucks and they gave me a bad choke or my 12V supply has a short in it. I am going to have to get out the multi-meter and check it when I get home. Should I have 12V there only when starting or should it be there when the key is turned at all? I will definetely check also to see if there is a vaccum leak as well. It must be that because it ran fine with the other carb once it would start. I have been meaning to replace the cap, rotor, plugs, and plug wires as well though. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 13, 2006 Share Posted November 13, 2006 The plate will remain vertical for a while after the engine is shut down (maybe about an hour). You'll have to check it when it's completely cold. The engine acts as a heat sink, and slowly releases heat into the carb and the choke spring resulting in the choke spring taking quite a while to cool down. That's as it should be though. The power should be there anytime the ignition is on. Sounds like you definately have power to it anyway. GD Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 I see. Would a vacuum leak cause hard starting or just the rough idle? If I can't locate a vacuum leak and the choke is engaging when the engine is cold should I go ahead and replace the cap, rotor, plugs and plug wires and see if that alleviates the problem? Or where would you go next if the choke works and there doesn't seem to be any vacuum leaks. I just don't have tons of money to sink into this. I am beginning to see that I should maybe see if carbsonly.com will just refund my money and go get a Weber. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 13, 2006 Share Posted November 13, 2006 A vacuum leak could cause some hard starting, yes. The engine will not want to run when cold with a vac leak. The ignition system can make it hard too. I would check the spark color out of the plugs when it's cold. If I were closer I would take a look at it. It's hard to diagnose stuff like this without being there. I've never personally had one that was *really* hard to start cold. I've had some that will sputter and die when cold unless you keep the RPM's up till it warms a bit, but not in recent years as I've become more adept at fixing stuff like that. It seems that no matter what you do with the Hitachi's they always have some problem. I've had them run as perfect as they were when new, only to have the float get stuck and strand me somewhere. I rebuilt that carb 7 times and it would work perfect for 2 or 3 months then one day the float would stick on it. Happened 5 or 6 times and I just got fed up and threw it in the trash. GD Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 GD- Thanks for all of the help. I am just going to check to see if I have a vacuum leak and start there. I sent an e-mail to carbsonly.com just in case this is due to improper adjustment on their behalf. Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 13, 2006 Author Share Posted November 13, 2006 I have heard that an easy way to find out if you have vacuum leaks is to place your hand over the carb intake and if the engine accelerates than you have a vacuum leak somewhere. Is this true? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 13, 2006 Share Posted November 13, 2006 No - if you block the carb intake, no vacuum will get to the carb to supply fuel. Air will be sucked through the leak, but the engine doesn't run on air alone, so it will die. Carb cleaner when it's sucked into the leak will cause the engine to speed up and smooth out slightly. GD Quote Link to comment Share on other sites More sharing options...
daeron Posted November 14, 2006 Share Posted November 14, 2006 The carb cleaner gets sucked up into the leak instead of air.. this air then goes into the engine and since its carb cleaner and not air, the engine revs up a little bit. Thats how this trick works. Another way to try and trace down a leak would be to get a stethoscope (yah, thats easy) or use a piece of rubber hose in one hear, plug the other ear off, and fish the hose around in the engine bay. put the end up near everything. You might hear it. this is NOT bulletproof with a hose, its much easier with a mecahnic's stethoscope which is designed for this.. but they ARE a handy tool, and some parts stores have chinamart ones for like, 10-15 bucks. Quote Link to comment Share on other sites More sharing options...
jk4138 Posted November 14, 2006 Author Share Posted November 14, 2006 Well I am almost positive that some of my starting issue is being caused by the choke because this morning I went out after it sitting overnight in about 30 degree weather and pulled the air filter housing cover to see the position of the choke plate after pressing on the gas twice. Sure enough the plate did not move one bit. It would start right away but just die in a few seconds without pressing on the gas. It took it about 5 minutes to warm up and then it seemed to run ok. Idle still is a little rough due to a small vacuum leak I am guessing. I am not sure if carbsonly.com gave me a faulty choke or if my supply wire is shorting out. This weekend I will run some diagnostic tests on it and see if I can pinpoint the issue. Quote Link to comment Share on other sites More sharing options...
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