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Desperately need tuning help!

Discussion in 'Suzuki Carry' started by rstickley, Nov 20, 2011.

  1. spaner

    spaner Well-Known Member


    I see that I am off on my own again.
    I got to the port diagnostic today and I can tell you that you do not need a tach to run the numbers as any steady state RPM base will show no change in the numbers. I would have thought that anyone who actually did the testing would have come across this revelation. No matter, I'm done with this section and off to make a video.

    I took the time to make up this graph hoping that it may help someone out but, if you haven't been in the trenches through this entire thread, you probably won't understand it. Sorry...

    [​IMG] VacuumPortNumbers.JPG
    Last edited: Feb 18, 2012
    Nutcracker likes this.
  2. fupabox

    fupabox Well-Known Member

    this info is pure gold for Suzuki owners...hope it is appreciated..new forum has no way to add rep. so I'll use smileys:D:D:D:D:D:D:D:D
  3. rstickley

    rstickley Member

    I have not had a chance to work on the truck lately but will soon. My father-in-law(owner of truck) came by and listen to it run. He is satisfied like it is and told me not to worry about it. In a way I am glad but this has been eating at me since I started and if I give it back to him like it is, I will always be wondering why it wont idle after choke opens. I am starting to think that the vacuum leak on the carb is the problem and I know he is not going to buy a new one. He wants me to put a snorkel on it. I may play around with it after I do that and see if I find something else that points to the problem.
  4. spaner

    spaner Well-Known Member

    Ha, ha fupa...""You must spread some Reputation around before giving it to fupabox again"" new site bugs, squish, squish
    I like smileys, but you only gave me 8...:(
    I would suggest that you check those ports again using an HG labeled gauge and then we can eagerly await dixx168s' numbers to compare and eliminate any question associated with the 3+2 vacuum configuration.

    This is a group effort. I make mistakes all the time. Just look at that dizzy check valve. I was driving around for a year like that and had to feather the throttle below 3TRPM. Bone head move, using the flipped check valve for a line plug. Anyway, looking at your posted numbers, they don't make any sense to me. You need a comparison for the 3+2 to be sure. Also, it's hard to eliminate every little problem in a timely manner without being able to be there to help you out. What I mean is, to check and eliminate something that would take 2 seconds.

    These are some of the things that I have noticed.
    In all of your pics, the #2 VSV set screw is to the max, max...
    Is the cooling fan coming on and killing the engine? Or is it holding idle?
    You asked a few times if you have to plug the dizzy line for timing, yes. Missed those.
    You seem confused a few times about the idle vs throttle-up adjustment. Same screw #3...example, engine hot and @ idle "on perch" #1, #3 "off perch" #2 (a hair)////park lights on.."on perch" #2 "off perch" #1, #3...choke on engine cold, "on slider" #5 "off perch" 1#, #2, #3
    This is why you have to set the screws from beginning to end, start to finish.
    At some point you were worried about the markings on the choke lever arm, not an issue.

    But, while waiting for those numbers from dixx168, I would suggest that you do the vac test again and also, test the choke systems' spring rate.
    With the engine cold(push-pin fully retracted), place a flat screw driver into the space on the left side of the choke coolant plunger. Pry the left choke lever up while using the plunger base for leverage. Should be about 4 finger difficult.

    Just reading back to the beginning, there is no way that the choke should be off in 60s on a cold engine. No matter how hot it is outside.

    My truck is done, but I'll help you out if I can.
    Last edited: Feb 19, 2012
  5. vortechys

    vortechys Member

    Different Carb??

    Spaner I have a question regarding my carb. My truck is a 1991 Suzuki Dump model DB51T. After reading this thread, I attempted to tune the carb, as per your instructions on page 2. I soon realized I have only one vacuum diaphram. Its the one on the bottom. I don't have A/C so maybe thats why. Anyway, I have located Adjustment 1 screw for accel. pump, adjustment screw 5 for fast idle adjustment, adjustment 4 for choke water pin and lastly what I believe to be adjustment screw 3 for base idle. I have no adjustment screw 2 for acc actuator:frustration:.
    So what is the best way to adjust this carb, when I have no screw 2? Any ideas? I have included some pics of the carb. Hope they help.
    Thanks! IMAG0182.jpg IMAG0183.jpg IMAG0184.jpg
  6. spaner

    spaner Well-Known Member

    3+2 cool.
    There are so many points on these carbs it's impossible to cover everything. You're pic reminded me that I wanted to post about the plastic arm. Someone wrote, somewhere, that it was broken on theirs. It is only in use during the choke cycle. It connects the throttle to the choke, so that when you step on the gas the choke butterfly opens dynamically. This is the whole point of having the gear and spring set and why a manual choke control retro-fit will not work well. Just don't drive it until it is warm and it will work fine.

    I assume you have the hard mounted cooling fan? You found a trick that I was going to mention. #5 is easiest to adjust if someone holds the petal to the floor for you. 1/4 turn, try it, 1/4 turn.
    Also, maybe easier to understand #3 idle base and throttle-up actuator if I describe it as a "floating idle base".
    Looks like you've found everything there. Having no Acc actuator, I would not set the idle below 1500RPM.
    Choke check closed
    Start engine
    Choke check cracked 15%
    #5 first running cold to 2500RPM,
    Engine hot, choke check open
    Set base idle with #3, and #1, and throttle cable
    #2 you don't have
    #4 is good if choke checked out ok
    #6 about half way in on mine
    #7 you don't have

    So, I guess its 5and4, then 3and1and cable, then 2and7, then 6

    Let me know if it blows up...
  7. vortechys

    vortechys Member

    Always wondered why I could not really set the idle below 1500. Your right I have the mechanical fan, not the electric one. So if I understand correctly. Set cold warm up idle with #5. Once warmed up, set base idle with #3 and tweek with #1. Then adjust mixture screw. Does this sound right?
  8. spaner

    spaner Well-Known Member

    Umm, yes and no.

    3and1 is a shaft balance. They should take equal weight at the idle position.
    5and4 are a combination adjustment. Only if 4 is needed to correct choke butterfly operation.
    2and7 would also be a combination adjustment.
    6 last yes.

    You see how difficult it is to explain.:frustration::frustration::frustration:
  9. spaner

    spaner Well-Known Member

    Vacuum port checks. Read those instructions on page 3 again.

    I think you'll find phrases like "while revving engine" and "only for a moment"
    Last edited: Feb 19, 2012
  10. vortechys

    vortechys Member

    Pretty much got it. I'll play with it, until I'm satisfied with it. Thanks for the help. I find your posts very helpful. Its much appreciated.
  11. rstickley

    rstickley Member

    This is the gauge I used and it is brand new and labled HG:

    The #2 set is adjusted that was so that it will idle up when fan or lights on.
    I was worried about the marks on the choke arm cause I messed with the adjusment by accident and needed to put it back and did not know how.

    You said: "But, while waiting for those numbers from dixx168, I would suggest that you do the vac test again and also, test the choke systems' spring rate.
    With the engine cold(push-pin fully retracted), place a flat screw driver into the space on the left side of the choke coolant plunger. Pry the left choke lever up while using the plunger base for leverage. Should be about 4 finger difficult." Could you please post a pict of what you are talking about. I am comfused on this.

    I really appreciate everyone's help on this thing. I am off of work Tuesday(Mardi Gras) and do not have my kids so I plan to work some more on it and will have more info then.
  12. spaner

    spaner Well-Known Member

    Thanks vortechys. Glad to help out, if I can.

    You caught me with an unclear post again! The gauge, I meant to post "inches of HG". You are using "cm HG", which could make comparison or interpolation difficult. Just to quote the HG" on the gauge.

    Also, I suggest doing the test again now that you know what to look for. My choke port, for example, snapped between 21HG" and 16HG" while revving the engine. Never above and never below, no matter what the base idle was set to. I am not yet convinced that the numbers between the 3+2 and 2+3 are the same, and won't be until I see the numbers from both you and dixx168 or vortechys, if he feels like doing it.

    I suggested testing the spring rate of the choke controller, because the system is mechanical and there should be no reason that the choke comes off in 60s, with a cold engine. It should not be possible.

    carb3-3.jpg carb4-4.JPG

    Fat Tuesday is for trading beads and getting drunk.:cool::cool::cool:
    Last edited: Feb 20, 2012
  13. rstickley

    rstickley Member

    I finally got around to testing the vac ports again after I installed a snorkel. This is what I got:
    Port 1) 2" at idle and drops to 0" with rpm increase
    2) 0" at idle and increases to 8" with rpm increase(high)
    3) 15" at idle and increase to 17" with rpm increase (FIRST IT WOULD DROP OFF THEN GOES TO 17" WHEN RPM INCREASE)
    4) 6" at idle and increase to 20" with rpm increase
    5) 2" at idle and increase to 12" with rpm increase
    I don't have a tach so I don't know what rpm is at but it is set to were it would idle smoothly on its own. All test were done at the port itself and not at end of hose and are in inches of Hg. I still have the idle issue but I maybe call it quits on this thing unless someone can give me any ideas to try. I don't know what to try next.
  14. dixx168

    dixx168 New Member

    where is this thing connected to?

    Hi Guys, i just thought id ask... i have attached a photo and would like to ask where is this thermal valve connected to?

    i have encircled the one with green which goes to the temp gauge, but the other one encircled with red is unidentified..

    please advise..thanks in advance

    Attached Files:

  15. spaner

    spaner Well-Known Member

    You notice that one is prior to the thermostat, the other is after..
    The one before is for the gauge, the one after is for the...fan?
  16. rstickley

    rstickley Member

    Come on Spaner, you got to have some idea for me to try!!
    Last edited: Mar 9, 2012
  17. spaner

    spaner Well-Known Member

    Of course I have ideas, but you're not going to like them.

    Did you check that spring rate on the choke?

    The f-port seems fubared though.

    If you really just want to fix it, I'd suggest two solutions.
    1) get a new carb from Don.
    2) install a manual over-ride push/pull choke cable. You don't have to change anything, just hook-up the hard-cable steel end to the choke lever, at the vacuum pull-off. This would allow control between 0 and 85% choke at anytime since the butterfly shaft is spring loaded. AND plug that f-port, so it's not ghosting on you.
  18. rstickley

    rstickley Member

    I did check the spring rate and it seemed fine. I too agree that it needs a new carb but the father-n-law came today and test drove it and is satisfied with it like it is. He said since he only uses it for hunting, it doesn't have to run perfect. So, he loaded it up and took it home. I am kinda glad but it is always gonna bother me that I didn't completely fix it like I wanted to. I showed him the vac leaks on the carb and told him that the next step would be to replace. He said if it gets to where he can't get through the woods then we would change it but for now, he doesn't want to spend any more money on it. Once again, I want to thank everyone for their input and patients. I learned a lot, good and bad.
  19. Colonel1

    Colonel1 New Member

    Hello guys, I'm new here so if I've posted in the wrong area, please forgive me. I have used this thread to get my vacuum hoses routed on my Suzuki/ Mazda Scrum and it worked great for me. I just have one question for now after reading all 8 pages of this thread I can't figure out what way I need to turn the carb mixture screw to make it run richer... I've done forum searches with no luck as well. So do I turn it clockwise or counter-clockwise to make it run richer??? Thanks in advance.
  20. Colonel1

    Colonel1 New Member

    Well, I found out that turning the mixture screw counter clockwise is supposed to make it richer. I turned and turned, checked the plugs and it did nothing! It won't idle without dying and runs rough. I guess I'm back at square one with this thread. Here's what I have;
    3+2 carb
    Vacuum lines are hooked up correctly (as far as I can tell)
    New carb rebuild
    New Plugs, Cap and Rotor
    Removed, and cleaned fuel tank
    Engine starts right up, choke works
    EGR seems to be working in and out
    Adjusting mixture screw does nothing, plugs are as white as they came when I took them out of the box and I've gone as far as I dare with the mixture screw counter clockwise (about 7 turns)
    Engine spits and sputters at low rpm's, seems to smooth out a bit at higher throttle, but sounds terrible at idle (when it does idle without stalling). Sometimes the engine surges to high rpms all by itself then slows down by itself...

    Can someone please tell me where to begin? I can tune all 4 engines on a Boeing 747 in less than a day but I can't seem to get anywhere on this thing after 2 days of messing with it! Argh!:mad:
  21. Jim Nelson

    Jim Nelson Active Member

    They can drive you nuts for sure. Have you tried spraying a little starting fluid around to check for vacuum leaks? That seems to be the problem more often than not.Several small leaks or one big one.On the last engine I did I replaced all the vac lines with silicone lines and it helped a lot.
  22. Don-in-Japan

    Don-in-Japan Member

    Pull the adjusting screw out and check it for straightness first. If there is a groove worn on the body, you should replace it. Also check inside the contact point inside the carb, to make sure there are no cracks anywhere around the casting. Some folks just love torquing these things down sometimes.

    All the way in (clockwise) is leaner.. all the way out (counter-clockwise) is richer

    Screw it in (gently) until it bottoms out.. back the screw out 2 complete turns, and with the engine at operating temps, and the choke off, slowly back the screw off counterclockwise in 1/8th turns. As you back it off, the RPM's should slowly rise. You will find a point where the RPM's will peak, and level out, regardless how much you turn the mixture screw. It is at that point where you want the adjustment. Right where it first hits that plateau.

    I used to run multi-carb setups in a few cars, and tune bikes from time to time, and is pretty much straight out of a Mikuni DCOE manual I've apparently lost somewhere.

    Of course, this is assuming everything else is working correctly.
    JMM likes this.
  23. Colonel1

    Colonel1 New Member

    Thanks Jim and Don! I'll try your advise in the next day or two. Sometimes it's easy to get frustrated and then it seems common sense goes out the door at the same time, at least for me anyway.
    The adjusting screw is brand new and just installed, never torqued down so no problem there. I'll let you know what transpires in a day or two.
  24. Patbox

    Patbox New Member

    Hi, another newbie here, I own a 91 carry DB51T like VORTECHYS

    I'm not able to locate ajustment screw #5. On a a cold start with choke open at 85%, my RPM goes up to 1800 on my tach. Also, on mine, the previous owner cut the link so I can't ajust my base idle with #3 so I'm using #1. Is that a big issue ?

    The truck start and idle pretty good and has enough guts & power and doesn't missfire but I'm only able to do 10 L/100Km on gravel road. Air filter is good and I installed a homemade snorkel on it to avoid fine dust to get in. the exaust smell like rich to me even if I ajusted the enrichment screw as recommended by Don-in-japan. By the way, thank you for all the precious infos. I'm living in a very remote region upnorth Qu├ębec and there's no mechanic around. I was able to do my snorkel using parts I found at the local dump (our local Cantire haha):p
  25. Colonel1

    Colonel1 New Member

    Well, I got around to working on the truck again today, here's what I found;
    Started it up and sprayed starter fluid around carb to intake area and vacuum lines, no difference.
    Began tuning procedures as per this thread and then noticed fuel leaking from the pump near the tank. I dried it off and started it again, fuel is leaking out of the top of the pump (factory pump), under the plastic cover that protects the switch. I'm assuming that the pump diaphram has got a hole in it so I took the pump apart and found that the diaphram is dry and rotted just like the ones were in the carb. I suspect this is from the old fuel that sat in the lines before I bought it. Could this be the problem? No amount of tuning on the carb seems to make any difference in the idle performance, always missing, sputtering, then dying... Maybe it is constantly starving for fuel or air is being pumped in the line with fuel? Spark plugs are still white as a ghost even after going to full rich on the a/f mixture screw... I'll be ordering the pump in the next few days hopefully. I'll know soon enough, but I was just wondering if this could have been the problem the entire time?
  26. Jim Nelson

    Jim Nelson Active Member

    I've had 2 fuel pumps go bad and 1 ran poorly before quitting and the other just quit so I guess you just don't know.When you did the carb. did you get into the metering rod in the top end? I did one a while back and got that messed up when I put it back together and it drove me crazy til I tore it apart again.
    If you order that $125 pump from G&R it works fine but causes a lot of static in the radio on the 2 I've used.
  27. Colonel1

    Colonel1 New Member

    Jim, I did take the top cover of the carb apart when I rebuilt it, I don't know if that is the " metering rod" you refer to, but it didn't run any different after I rebuilt the carb than before. I'm assuming because of that, it isn't the problem. I did order the $125 pump from G&R as well as a new filter. I also found the old filter to be really dirty, maybe the combination of a weak, leaky pump and partially clogged filter is the problem. I should know in a few days when the parts arrive. Thanks again for the help. Will post the results as soon as I know...
  28. Colonel1

    Colonel1 New Member

    Got the new fuel pump and installed it along with a new filter, no difference whatsoever! Then I turned the mixture screw down till it stopped and it started running smoother, stayed running and doesn't stall!. Plugs still indicate that it is running way lean! Nothing seems to make sense... Anyone know what I should do? I'm afraid if it continues to run this lean, I can expect a burnt valve to be the next problem. No leaks from vacuum lines or intake/ carb, all new fuel system from tank forward now yet plugs are still as white as a ghost. If I turn the mixture screw out even 1/2 turn it starts sputtering and idle becomes erratic again...:confused:
    Last edited: Oct 8, 2013
  29. Colonel1

    Colonel1 New Member

    Any help would be appreciated on above problem. Have had the carb apart and back on the truck at least half dozen times now to no avail. Only change is plugs look good, (a little tan coloring to them), and now it starts, runs through the choke sequence, then either runs ok for a few minutes and then stalls, or just stalls after choke opens. Ran seafoam through the tank and crank case, no difference....
  30. Doddy

    Doddy Member

    intake swap

    I have to swap my intake and here are the pics of the used one i am putting on......please dont ask what happened to the other one. lol

    I am wondering how many of these lines are actually needed. I have removed the canister filter and put those vacuum lines into my intake pipe, and i have also removed the cold/heat vacuum and its parts. seemed to just need so carb adjustments and it was good.

    toppic1.jpg bottompic2.jpg

    Attached Files:

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