- Thread starter
- #41
Troll, i never plugged the two lines coming out of the dizzy, they were like that when i got the truck. Should they be getting constant vaccum?
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frustrated with aisin carb
- Thread starter badass
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Troll, i never plugged the two lines coming out of the dizzy, they were like that when i got the truck. Should they be getting constant vaccum?
why did you quote donny paradise and reply to Troll? s*** man! get a grip.......
in your last bad picture, the centre top fitting is where the power valve connection is on my 75, not sure if it's the same on your year, maybe someone can chime in, but upon hooking it to manifold vacuum, mine ran tolerably well
you could always pick up a used holley to slap on it while you wait for your jimc rebuild, not the ideal carb, but if it's only for a couple of months...and lots of folks here would probably trade you a holley for a beer
, hell I'd give you mine, but the shipping would be a killer.
you could always pick up a used holley to slap on it while you wait for your jimc rebuild, not the ideal carb, but if it's only for a couple of months...and lots of folks here would probably trade you a holley for a beer
, hell I'd give you mine, but the shipping would be a killer.- Thread starter
- #44
ok, now that i actually understand the vaccum readings, i checked it, readjusted the carb at 700 rpm, i get a contant reading at 20 on the gauge. When i push the gas pedal enought to make it bog down a little, the gauge goes down to 1 or 2 then comes back up to 24 then back down the 20 gradually. However, sometimes when i all of a sudden rev it, it backfires out of the carb.i
That sounds like good vacuum with a need for timing adjustment.
So, did you ever get around to the timing adjustment? if not,
thats a direction to look at 
I second Pin_head, idle too high will definitely cause it to run with the mixture screw all the way in. When I set up the mixture screw on a carb the engine is barely running, ie idle screw backed way off.
You have to have a vaccum source to the distributor.
Nothing will even start to work right until you do. And make sure those ports are clean.
Read and learn.
https://forum.ih8mud.com/showthread.php?t=118998&highlight=stock
Nothing will even start to work right until you do. And make sure those ports are clean.
Read and learn.
https://forum.ih8mud.com/showthread.php?t=118998&highlight=stock
Sean- Concerning the rebuild of the carb... it sounds like David has given you some sound advice.
In the meantime... this thread was very helpful to me in getting my '78 desmog vacuum lines set correctly. Perhaps someone on the board can update or create a faq that is '79 specific...https://forum.ih8mud.com/showthread.php?t=121581
Trollhole- I ran my cruiser for years w/o the vacuum advance working... it had corroded. You can advance the timing and run very well without it... but, now that I have it working... WOW!
Sean- back to setting your timing... if you have the idle at 700 rpm's that is close enough to tackle the timing. Connect the vacuum gauge to the intake manifold and adjust your dizzy until you get the absolute highest value you can get... I then back off from that point about 1/2 inch. If you find that you have pinging, back off another 1/2 inch of vacuum.
Back to the vacuum advance on the dizzy... I'm assuming that the '79 has only vac advance ('78 has both advance and retard which on a desmog the retard is typically disconnected and capped). Take the dizzy cover off and with a vacuum tube connected to the dizzy vac port, provide suction to ensure the diaphragm is working.
EDIT: Spend some time understanding the thread Trollhole provided. Please share with us any differences you are seeing between your '79 and what is documented for the '79.
In the meantime... this thread was very helpful to me in getting my '78 desmog vacuum lines set correctly. Perhaps someone on the board can update or create a faq that is '79 specific...https://forum.ih8mud.com/showthread.php?t=121581
Trollhole- I ran my cruiser for years w/o the vacuum advance working... it had corroded. You can advance the timing and run very well without it... but, now that I have it working... WOW!
Sean- back to setting your timing... if you have the idle at 700 rpm's that is close enough to tackle the timing. Connect the vacuum gauge to the intake manifold and adjust your dizzy until you get the absolute highest value you can get... I then back off from that point about 1/2 inch. If you find that you have pinging, back off another 1/2 inch of vacuum.
Back to the vacuum advance on the dizzy... I'm assuming that the '79 has only vac advance ('78 has both advance and retard which on a desmog the retard is typically disconnected and capped). Take the dizzy cover off and with a vacuum tube connected to the dizzy vac port, provide suction to ensure the diaphragm is working.
EDIT: Spend some time understanding the thread Trollhole provided. Please share with us any differences you are seeing between your '79 and what is documented for the '79.
- Thread starter
- #50
Now that is some good info, i will go get to work and report back. Just a question if i run a line from the carb for vaccum advance to the dizzy, there are two holes which one do i hook it up to?
- Thread starter
- #52
the one that is ported on the carb. and the outer one on the dizzy
donny, i have a double vaccum advance, meaning two holes, should i plug it up to the hole closest to the dizzy or farthest. Also, when i do plug it up, it makes no difference, is there supposed to be a difference during idle or is the difference noticable at higher rpms?
farthest from the dizzy, no change @ idle, only at higher rpms
- Thread starter
- #55
I believe someone said that a 79 carb doesn't have a power valve, i assume the carb is a 79 model, it has 9F13 stamped on it meaning June 13, 1979.
So are you gonna tell him to run it without it being connected?
Do it right, do it once.
Colorado Boy-74-FJ40
I may grow older but I refuse to grow up!
Hey badass, I am an aircraft mechanic by trade and consider myself to be a three to four banana kinda mechanic. I don't have the balls big enough to tackle a carb though. I give you props for trying! Good luck
- Thread starter
- #58
Yea i usually just do whatever on the rig, can't really make myself take it to a mechanic after the bad experience i've had. In the last 3 weeks, i've done a front axle rebuild, mini truck ps, and now rebuilt the carb. Thanks.
I think that's how you learn(also learn from those dreaded mistakes) about your vehicle and what makes it tick. It's nice knowing most of how the vehicle is put together so when you decide to take it apart with a bang! you can fix it on trail.
You may even get to "learn" about those improperly ground cams that somehow made it into your engine causing years of headaches with the smog guys and your sanity to be tested to the limit. But when YOU figure it out the reward is so worth it.
Nope... Just saying it will run well w/o vac advance. If it has been capped since he purchased the truck I'd bet that the mechanism will not actuate anyway... for me, I had to pull the dizzy, remove the diaphragm, and polish the advance shaft to get it working again. At the time of my post, the last thing I wanted to see him do was pull the dizzy. The truck will run fine without it (vac advance).
I completely agree with your point... "Do it right, do it once." At that point in the thread I was hoping Sean would stay focused on one thing at a time in an attempt to isolate the problem.
Thanks for helping me clear up any confusion my post may have created.
gt
