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Installing new carb!

Discussion in 'Honda Acty' started by Littlestan, Nov 24, 2014.

  1. Littlestan

    Littlestan Member

    Finally got the new carb from Yokohama, going to start the swap in about 2 hours. Hoping it should be fairly straight forward.

    Has anyone cleaned or changed out the vacuum hard line with silicone or rubber hoses? I'm wondering how much sludge or
    carbon could be stuck in all those lines and I'm thinking it might be a good idea to just replace them all.

    Whaddyafigger?
     
  2. What year ACTY are you changing the carb on?

    And, how much did the carb cost? Is it new, or rebuilt?

    I'm having problems with my 1992 ACTY HA4.
     
  3. Littlestan

    Littlestan Member

    Hey CLC,

    It's a 1994 ACTY SDX, with A/C. The carb cost nearly $400 after taxes and $45 in Fedex charges. Link here: http://yokohamamotors.net/store/product319.html
    It states it's a rebuilt on the site, but the billing/shipping label says NEW. Weird...

    What kind of problems are you having? I had to bypass the air cutoff vent solenoid because my truck wouldn't idle... it runs pretty good for the most part, aside
    from barely not starting first time, and having to start it twice when it's hot. I just can't leave it like that knowing it's on it's way out even if it IS currently working.

    I'm going to take a few of the vacuum hard lines off and run something through them to see if any crud is built up and report back.
     
  4. Littlestan

    Littlestan Member

    Wow, is that ever a nest of hoses in there! Took forever to get it apart, but I think I've got the hang of it for putting it back together. Hopefully. xD

    Gonna do an hour or so of cleanup (there's a ton of oil and grit everywhere) then try to get it all together before work.

    Onwards!
     
    Last edited: Nov 29, 2014
  5. Littlestan

    Littlestan Member

    Glad you figured out the issue CLC! That solenoid is a pain in the ass... :(

    It decided to piss out on me for the last two days, which made getting everything back together a wet and cold experience. (no garage)

    But it's up and running! Some things I learned:

    - Assemble the bottom of the cover to the bottom of the carb AFTER pulling the 3 vacuum hoses from the engine and feeding them through.
    One of them is super long (red hose on on my truck) so you can leave that and feed it through last. I tried to do this with the hoses still on the
    engine and, after much cursing, figured it out.

    - When you order a rebuilt carb from Yokohama, it comes rebuilt but not necessarily in running condition. Either they, or customs, had mishandled
    it and one of the metal vacuum nipples had been busted off. Thank gad I had the old carb to swap the old cover on or it would've been an entire
    day waiting on JB Weld to work it's magic.

    - Check the working condition of the air vent cutoff solenoid BEFORE installing the carb. Mine was
    in a 'stuck' position and I spent 2 hours trying to diagnose other things thinking 'there's no WAY it could be the solenoid, it's rebuilt!!'.
    I also suggest removing the old bullet connectors and putting new style connectors on; mine were touchy.

    So now it's up and running but it's running fairly rich, 12 - 13 A/F ratio idling and around 13 - 14 A/F ratio on the highway... is this a float bowl thing? Something else I
    should've checked before installing it?

    Also, I need an idea of what position to set the plastic pilot screw. I don't trust the position on the old one at all as it's mostly screwed all the way in.
     
  6. Wish I could answer some of your questions, but I have no idea.
     
  7. shogun

    shogun Active Member

    @Littlestan
    the attached pics do not work, I also get: Invalid Attachment specified

    Can you try once more, or use a free picture upload and post the links here, thanks
     
  8. Littlestan

    Littlestan Member

    Weird, I used the built in uploader and it comes up fine for me. :( Here's some new links:

    [​IMG]

    [​IMG]

    Just shows the difference in general cleanliness really. There is one thing I noticed though; in the 'exhaust' side of the carb,
    there's a needle that comes down into the throat on the old one, but not the new one. Maybe a slight design change?

    I may have to take the carb off and check the float this weekend... it is running mega rich across the board. Glad I had my
    narrowband A/F meter put in before I did this or I wouldn't have a clue. I will be very unimpressed with Yokohama if it ends
    up they didn't set it right. :(
     
    Last edited: Nov 29, 2014
  9. Littlestan

    Littlestan Member

    Update time...

    It dropped 10 degrees here overnight so we're in freezing temps now. Truck did not start
    at all today. Time to remove the carb.

    Took the carb off and checked the float. It's within spec. (16mm +/- 1mm)

    I double checked the air vent cutoff solenoid and it's working just fine. Then I thought 'what about the OTHER solenoid?'

    Here's what I found:

    [​IMG]

    [​IMG]

    Guess which one is the new one from the rebuilt carb and which one is the 'old' one?

    Not only is the 'new' one cruddy and worn, it was stuck in the depressed position and wouldn't move
    until I yanked on it. Now it moves but it's severely sticky and catches. Needless to say, I'm putting the 'old'
    one in and I fully expect the overly rich condition to be solved now.

    Yokohama will be hearing from me. Is there a representative on the forums I can contact directly?
     
    Last edited: Nov 29, 2014
  10. None of the links work. I Can't see any of the pics.
     
  11. Littlestan

    Littlestan Member

    I'll try yet another image hosting site then and see if that works.
     
  12. Littlestan

    Littlestan Member

    Another update: truck now starts perfectly fine in freezing temps from bone cold. However, it STILL runs rich across the board.

    I really, really should have removed the main jets and compared those as well... this is my next step. I'm currently burning
    gas at nearly twice the rate I used to, with noticeably less power.

    On a positive note, I've got the removal/installation process down to just over 2 hours now! xD
     
  13. Littlestan

    Littlestan Member

    Ok, carb is out and on the bench for the third and hopefully last time. Removal was only 20 mins this time!

    Before removal I tested all the exterior things I could get at first and confirmed they all function correctly and smoothly.
    (solenoids, choke, etc.) They all appear to be set in the same manner as the old working carb as well.

    The only way I could get the truck to start was to have some one crank it over while I very slightly opened up the intake
    side butterfly... confirming that there's not enough air coming in and an overly rich condition exists in the circuit somewhere
    upon startup. Also, once fully warmed and the choke has the intake butterfly open fully, even on the highway cruising I have
    an air fuel ration of 12.5 - 14... far too rich. I know that a narrowband is no good for performance tuning at all speeds due to
    it's inaccurate nature, but at idle and cruising (where it's most accurate) it gives a very telling story of double the 'bars' lighting
    up on the gauge. Gas consumption is hugely noticeable versus the old carb.

    All the jets are identical, and the valve in the slow jet is free moving and operating just fine.

    I guess all that's left is to break it down piece by piece and compare it to the old one, while blowing out all the air passages and
    holes until I find something inconsistent. I'll report back tonight or tomorrow with my findings.

    In the meantime, here's some pics of the differences in the outtake throats, starting with the old carb: (hopefully working for everyone now)

    [​IMG]

    [​IMG]
     
    CompleteLawnCare likes this.
  14. shogun

    shogun Active Member

    Thanks for the pics and info, helps us all in future with similar probs. Good Luck and keep us updated.
     
  15. Littlestan

    Littlestan Member

    Update time again. Totally disassembled and sprayed/blew out every single passageway and jet. There was no noticeable blockage
    or dirt. However, Yokohama fails again in the rebuild expectation as the emulsion tubes under the jets were never removed. There
    was a fair amount of corrosion and they were incredibly difficult to remove without destroying. Had to soak them and then heat them
    for them to finally squeak out. The only one that had blockage was the one under the slow jet, and just the top 2 holes were plugged.

    Cleaned them out, put everything back together and installed it back on the truck this morning. Started fine enough, but exhibited
    erratic idling. Let it heat up, idle smoothed out and took it for a drive. Rich as hell still. Here's a pic of where the A/F likes to be
    at now with the new carb at cruising speed, whether it's at 60 km/h or 100 km/h.

    [​IMG]

    The old carb only lit up the first 4 bars in comparison. I'm currently at a loss as to how there's not enough air coming through.
    Maybe some of the emission systems like the charcoal canister aren't up to snuff for providing additional air?
     
  16. Littlestan

    Littlestan Member

    Going to be replacing all vacuum lines and testing every valve this weekend in the vacuum system. In all my previous
    experiences with tinkering or replacing carbs in vehicles, I've only ever run into a constant lean condition that can easily
    be narrowed down to things like fuel pump/filter failing, or jets being clogged. This is bizarre to say the least.

    Does anyone know where I can source a new EGR valve or how much vacuum to apply to it to test it? Circled in yellow:
    (I borrowed your pic OM, hope that's ok)

    [​IMG]
     
  17. Littlestan

    Littlestan Member

    Took a quick look at my PCV valve today. Here's what it looks like:

    [​IMG]

    Tan colored discharge inside the tube, water in the inlet hoses attached to it. Once I removed it, it became
    apparent that the valve inside has been stuck for quite some time. Shaking it produced no movement or rattle.

    Heading to Lordco/Canadian Tire to source one now. The part # is 17130-PN3-003 if anyone is interested.
     
  18. Littlestan

    Littlestan Member

    Couldn't find a replacement for it, so I'm attempting to clean out the crud and gunk
    by soaking it in a shallow dish of Seafoam. I'll give it 4 hours or so to work it's magic
    then see if it's loosened up.
     
  19. shogun

    shogun Active Member

  20. Littlestan

    Littlestan Member

    Thanks shogun, I'll give those a shot if Yokohama can't source one for me. I managed to get the current PCV valve cleaned
    up and moving freely again. Installing it improved the shutoff 'rundown' time so it's nearly instant now, but no change to A/F ratio.

    Onwards...

    I've been analyzing the manual diagrams for the emission and vacuum routing and really getting to know
    how the carb works internally with the other systems. Having the old carb on the bench and disassembled
    makes this easy after spending some time with it and some compressed air.

    Here's what I'm looking at:

    [​IMG]

    Top left circle is #2 - Thermovalve 'B'. Bottom circle is #20 - Canister, or Fuel Purge Valve Canister, as we know it.

    If you trace the routing on the diagram, you'll notice it leads directly to the outtake side of the carb, just before the butterfly valve.
    Looking closely at the throat of the outtake side, you'll notice several small holes placed strategically around the bottom, shown here:

    [​IMG]

    Blowing air into both of the ports that the thermovalve and canister are connected to produces a jetstream through those holes.

    Here's my theory... the reason the old carb was operating in a mostly correct A/F ratio across the board is because it did not
    produce the same amount of gasoline flow as the "rebuilt" (freshly cleaned) one. While the vacuum systems became old and
    provided less and less air over time, so did the old carb provide less fuel as varnish and buildup occurred. Installing the rebuilt
    one restored the original amount of gas flow but overpowered the current lack of air available.

    The ratios are close enough that the truck runs still, without surging or hesitation. But considering the smell of gas coming from
    the exhaust, the difficulty of starting from cold and what the narrowband is telling me, it must be very close to not being able to
    operate. As it happens, Yokohama just updated their site to include none other than the thermovalve and canister in question
    for the Acty, reinforcing my suspicions.

    http://yokohamamotors.net/store/page61.html

    I'm ordering them tonight and will report back once I receive and install them. What a colossal pain in the ass this is becoming. xD
     
  21. shogun

    shogun Active Member

    Thanks for sharing this experience, info and the pics with us. I have bookmarked this thread.
     
  22. TRAX and HORNS

    TRAX and HORNS Well-Known Member

    Totally embarrassed by saying this but a while back I had a honda that ate my lunch. Convinced it was a fuel / delivery problem and after installing new fuel pump, new fuel filter, new rebuilt carb. from Yokahoma Motors and clean complete fuel system including tank it still wasnt right. Did exact same thing as if old carb. was on. Hard to start, rough idle and bogging.
    Went through air filter system, spark was good (so I thought). Last thing I decided to do was pull dist. cap. What I found was the three contacts completely oxidized and a small crack next to rotor button. After cleaning contacts noticed that half of them were gone. Cleaned contacts reinstalled and it ran like new. Ordered new dist. cap and rotor and ran even better, Not to say this is your problem but dont over look it.
     
  23. Littlestan

    Littlestan Member

    Hey TaH!,

    Thanks for the info, I'll give it a peek at tomorrow but I have my doubts as to it being bad seeing as it runs just fine albeit very rich.
    Can't hurt to check though, thanks again. :)

    Parts were shipped from Yokohama today, if I'm very lucky they may be here by Friday. The carb took just over a week to arrive so I don't expect
    them to show up till next week, realistically. I suppose I could take the thermovalve and canister off the truck and test them to give an idea
    if my theory has any bearing. I'll do that the next time the rain stops and update.
     
  24. Littlestan

    Littlestan Member

    UPDATE!: Tested the 'Thermovalve B' today using this method;

    - Started the truck from cold.
    - Immediately removed the top hose and felt powerful suction, nothing on the barb. Reconnected.
    - Removed the other two hoses one at a time and felt nothing on either the hoses or the barbs.
    - Let truck warm up to operating temperature completely by idling for 20 mins or so.
    - Removed top hose and felt powerful suction from the hose, nothing on the barb. Reconnected.
    - Removed the other two hoses one at a time and felt nothing on either the hoses or the barbs.

    I think it's safe to say that Thermovalve B is not operating correctly. lol

    Will update again when parts come in!
     
  25. Littlestan

    Littlestan Member

    It always amazes me when I can order something from halfway across the world, separated by thousands of miles of ocean, and
    receive it faster than I can on my own landmass. 4 days is a record I think!

    Parts looks shiny and new, I'll post pics once I've installed them after lunch and hopefully this whole thing can be case closed!
     
  26. TRAX and HORNS

    TRAX and HORNS Well-Known Member

    When i ordered my carb. From Yokahama Motors it shipped on a
    Monday and was here in Austin on that Thursday.
    Pretty efficient.
     
  27. Littlestan

    Littlestan Member

    Ok, I'm back with mixed success.

    Upon removing the Thermovalve B, I discovered the plastic piece on top had been broken for who knows how long.
    It had cracked along the seam where it joins the brass body.

    [​IMG]

    I also noticed a slight design change; the old one had a flat, solid bottom where the new one was concave. Probably
    transfers heat more efficiently that way.

    [​IMG]

    Before changing the canister, I started the truck up. It fired up immediately, which is a major improvement and settled
    into a smooth idle. I used the same testing procedure as before to check if the operation of the valve was any different
    than the old one: removed the top hose and felt a powerful suction. Reconnected. Took off the hose pointing towards
    the front of the truck and felt nothing on the hose, but a suction through the barb! Progress! :) Reconnected, and
    went for a test drive.

    Definitely smoother idling, it didn't smell like fuel idling at a stoplight and I think it sounds slightly more quiet now. Win-win!
    However, the A/F ratio was unchanged... still rich. Came back home, shut it off, then turned it back on again right away and it started
    no problem. That was always an issue before even with the old functioning carb, so the thermovalve definitely had something
    to do with it.

    Let it cool down some, then changed out the canister. This is a royal pain to do without a lift, fyi. Once I removed it, I blew into
    and sucked air from all the ports and compared the differences with the new one. There was no difference, but the new one is
    noticeably lighter than the old one. Installed the new one, started it up again (so quick now!) and went for another scoot.
    No noticeable difference. The A/F ratio remains on the rich side.

    I'm at the point now where I feel like maybe they're actually intended to run on the rich side. There's now no more gas smell, and
    there's never been any colored smoke coming out of the exhaust pipe, other than the usual white vapor on bone cold startup. When
    I try to adjust the pilot screw, there's no discernible difference between screwed all the way in, or out.

    I'll drive it for a few weeks like this and record my mileage. If it's crazy low, then I'll look into this more but for the time being I'm
    done messing with it. :)
     
  28. Littlestan

    Littlestan Member

    Well, that didn't last long. I just can't let it go! lol

    A couple things: the valve I replaced was the Thermovalve A, not B. I'm glad I did because *wow* does it ever start and idle nicely now!
    Engine hardly kicks over and it's up and smoothly running. So I decided to check the EGR and Thermovalve B operation. If you look at the
    diagram I posted a few posts back you see how they're connected inline with each other, like this: Engine --> EGR --> Thermovalve B --> Carb.

    I started the truck cold and removed the EGR hose. No air, which is normal, then reconnected. I also took off the hose from Thermovalve B
    and checked, but seeing as it's a one way street (air coming from the EGR only) I didn't expect anything. Nothing. Alls well so far.

    Let the truck warm completely up, then took off the hose from the EGR again. No air, which is NOT normal. Revved up the engine while I checked
    again and STILL nothing. Reconnected the EGR hose then took off the Thermovalve B hose; no air. Revved up the engine, still no air.

    Is it possible that ALL the vacuum related things are buggered up after 20 years?! xD

    Looking for replacement parts again and will order tonight if possible. If anyone has any thoughts or ideas please let me hear them! :)

    TaH, I checked under the distro cap and all seems well with the rotor and points. Thanks again.
     
  29. Littlestan

    Littlestan Member

    EDIT: EGR is fine, I misunderstood the function of the vacuum port on top. Thermovalve B is confirmed working as well.
     
    Last edited: Dec 15, 2014

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