Any Aisin Carb Gurus in Charlotte Area?

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roadstr6

roadstr6

10 Year
Joined
Apr 10, 2013
Threads
90
Messages
5,830
Location
Weddington, NC
Hey Guys,

I'm trying to run down a small off-idle stumble issue in my 40. Runs perfect with a little choke but with choke off it hiccups upon initial acceleration. After the small hiccup it picks right up and runs great. I am suspecting the accelerator pump but before I tear into this thing I'd love for someone "in the know" to take a look at it and point me in the right direction.

Anybody in the Charlotte area who knows their chit when it comes to the early Aisin's that would be willing to take a look at what I've got? I can come to you.
 
Go see mark and Johnny in fort mill or call trollhole and order a new one!
 
How many HG of vacuum does the motor pull at idle?

When you quickly give it full throttle does it go to ZERO or like 5?

Does it rebound fast when you do this?

Rock steady needle?

Have you checked for vacuum leaks?

Double checked the timing? Tried to tune the timing and carb by seat of the pants?

Lots of stuff that gets blamed on the carb has to do with timing and with vacuum leaks. especially on an inline six with the afflicted manifold design of the F/2F.


Go here:

http://www.ih8mud.com/tech/carbinfo.php

Ed Cook showed me how to adjust carbs in person, I use his method.

I start with a valve adjustment after checking compression (no amount of tuning makes up for a lack of compression)

Then I get a hand held tach, a vacuum gauge and a timing light.

Setting timing and carb adjustment are done together - when you change one, it changes the other. You can push it too far and limit drivability on both timing and carb adjustment/jetting.

Then go on a test drive - make small tweaks from there.

It is amazing how well you can get a motor running with this process.
 
kulangot said:
How many HG of vacuum does the motor pull at idle?

When you quickly give it full throttle does it go to ZERO or like 5?

Does it rebound fast when you do this?

Rock steady needle?

Have you checked for vacuum leaks?

Double checked the timing? Tried to tune the timing and carb by seat of the pants?

Lots of stuff that gets blamed on the carb has to do with timing and with vacuum leaks. especially on an inline six with the afflicted manifold design of the F/2F.


Go here:

http://www.ih8mud.com/tech/carbinfo.php

Ed Cook showed me how to adjust carbs in person, I use his method.

I start with a valve adjustment after checking compression (no amount of tuning makes up for a lack of compression)

Then I get a hand held tach, a vacuum gauge and a timing light.

Setting timing and carb adjustment are done together - when you change one, it changes the other. You can push it too far and limit drivability on both timing and carb adjustment/jetting.

Then go on a test drive - make small tweaks from there.

It is amazing how well you can get a motor running with this process.
Click to expand...

Listen to this man... He helped me get mine tweaked, and it's running great!
 
Thanks for the info, guys. I have read a ton of info on timing/carb adjustment and your advice is solid. I can do the basic timing check, valve adjustment, leak check etc but I don't have a vacuum gauge. I was hoping that there was somebody here local that wouldn't mind spending an hour with me to show me in person the way Ed Cook showed you, kulangot. I'm just now getting a chance to drive this thing. I have sorted out the electrical gremlins, fixed my brake issues, installed a new radiator, etc. The last thing I want to do now is to start messing with things like ignition and carb settings and knock the 'Cruiser back out of service, leaving me floundering around in the dark chasing new issues. When I've had some fun with it, I'll start experimenting.

I don't think tossing the carb and buying a new one from Trollhole is the way to go. The PO says this one was rebuilt a year or two ago by a guy who was highly recommended on this forum. Maybe has 500 miles on the carb rebuild. I have his name and the receipt at home. Valves were adjusted recently by the PO's LC mechanic. This LC runs great. Starts right up. Runs 60-65 on the Hwy. There are no other issues. Just a slight hiccup coming on/off the throttle when the choke is off. It has a header so I thought maybe missing the heat riser was the problem. I installed a fluid riser from Man-it-ain't-free and that may have helped a little but the problem persists. If anybody knows their way around the Aisin and has a few minutes to spare, please take me under your wing and show me the way.
 
Get a vacuum gauge - they are dirt cheap.

http://www.sears.com/actron-cp7803-vacuum-pressure-tester/p-00902179000P

Go here and learn to use it:

http://www.therangerstation.com/Magazine/Summer2003/VacuumLeaks.htm

You can really learn a lot from knowing how to use this tool. There are many others such as an Osiliscope scope, bore scope, leak down tester, radiator pressure tester or oil analysis that be amazing when troubleshooting and super tuning but none that are as simple to use and inexpensive as a simple vacuum gauge!

Everyone who works on their truck should have one of these, when I was a kid my dad would always have one dash mounted.

Having one will teach you how to drive more economically as well. Drive for maximum vacuum.
 
your symptoms remind me of the failing accelerator pump I had on my 77 celica gt....doesnt hurt to check all the bases but I think you may thinking right...good luck
 
The carb was rebuilt in'02 by Jim Chenoweth of TLC Performance in Ohio. I don't know how many miles ago but I know it hasn't been more than 10,000. I checked for vacuum leaks and can't find any. The accelerator pump seems to be squirting a pretty good stream. The timing was somewhat retarded at -3 degrees BTDC so I bumped it to the BB @ -7. It's got a lot more power now but the hiccup is still there. Anybody got any ideas? I haven't had time to pick up a vacuum gauge.
 
And Jim is tops in carb building . It was done right back then, but again too many years sitting / driving. Sitting can hurt one also by just getting gummed up. Maybe run some Sea Foam thru it also.
 
Good advice, Darin. I can't tell you how many motorcycle carbs I've rebuilt from just sitting idle with ethanol fuel in the bowls. Maybe I'll pick up a rebuild kit and give it a shot. For now I'm driving it with the choke 1/4 on just to get some windshield time.
 
I rebuilt the carb on my 40 over the last couple of days. I used Pinhead's Youtube video series as my guide. It was not as difficult as I thought. The rebuild was a success. 'Cruiser runs awesome now. If anybody is on the fence about doing this rebuild, take the plunge and do it. You might be amazed at the difference it will make! If I can assist, let me know. I am an expert now...not really...but I will lend a hand if needed.
 
Darin, I have some background with little British cars, Triumph, MG,etc. and you find webers swapped in on lots of those old cars because people didn't understand the factory SU carbs and didn't know where to start with rebuilding them. The original carbs worked fine and most of the problems people had were ignition related and had nothing to do with the old SU's. The webers were almost always oversized for those cars. Most ran the same downdraft 38/38s that people tend to put on 'Cruisers. They were problematic on the LBC's and I would expect the same thing on a cruiser. I'm not a weber fan, although a properly set-up row of weber sidedrafts on an old classic european car is a sight to behold and runs like stink if you can keep them all in tune. For the old F engine 'Cruiser the Aisin does just fine. I assume the carbs trollhole sells are Aisin knock-offs, right? What is the reliability of those? Can you get rebuild kits for them?
 
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