Distributor Question (1 Viewer)

[Boaf 32]

And the broken needle is out. Ordered a replacement.

Will keep all posted.

Boaf

 

[brian]

Weber Jet Kits Base gaskets and Chokes
this is where i was getting jets from.

 

[Boaf 32]

Weber Jet Kits Base gaskets and Chokes
this is where i was getting jets from.

Too funny, I just ordered from there. Great minds...

 

[Boaf 32]

So with the new fuel adjuster in place, all went well. Also replaced the fuel filter (a see through Wix) because I thought I should. Replaced it with a 1985 Jeep Wrangler filter that had the return on it.

The first 15 miles, awesome. Go up the hill in 3rd gear with no hesitation.

The bogging down soon returned. Thought, oh crap, was that not the only problem? Well soon found out what the issue was.

My fuel pressure was great until I got to the high way. Then a backfire, a cough out the carb and then struggle to the side of the road. The motor kept running and opened the hood. Bubbles in the glass fuel bowl. Thought at first that the Jeep filter was at fault. Niet! Took the fuel hose off the carb. Cranked it over (in 30 degree weather) and no fuel even squirted out of the hose. Really, Fuel pump, crapola!

After the tow, put it in the garage and ordered a new fuel pump. Also ordered a factory fuel filter and will remove the "new" fuel return, worked fine without it, but thought I should add it. Don't f with a good thing!

Guess I will deck the Halls with mounds of fuel pump, fa la la la lalll la la la lall. I could think of worse things to do. . Spending time with the in-laws for example Aghhhhhhh! kidding

Again, will let you all know. Merry ho ho.

Boaf

 

[Dizzy]

Hang in there, on all fronts. Did you get the carb's Lean Best Idle adjustment and jets up to spec? How is that choke working for you?

 

[Boaf 32]

Hi LCer's,

Below is a picture of my old fuel pump (left) and replacement from SOR. Obvious differences are the number of screens / filters under the bonnet. All other dimensions are the same and it fits (I had to rotate the bowl because the fuel inlet hit the motor mount.

Any reason for the differences in old and replacement or is it just evolution of an old design?

Thanks,

Boaf

 

[Boaf 32]

The stock Aisan 2F carb has 38/40 mm throttle bores, so the idea that it is too much air flow is probably incorrect. More likely a jetting problem.

The screw is only for adjusting the idle fuel mixture. It has no effect when the throttle is opened. To change the running mixture you need to change the main jets.

I'm not a carb hater. There are a lot of different carbs out there and most of them work just fine. The Stock Aisan is a good carb, but it is a little more complicated than a Rochester or Holley.

Pin_Head,

What is the standard size Main Jet (in the bowl) for a Weber 38 / 38?

Boaf

 

[Pin_Head]

I don't know, but I would guess about 1.5 mm.

Webersarge would know

 

[thebigredrocker]

Should be able to run 50 to 60 idle jets , 145-150 mains and 165-180 air correctors on most Cruisers . Compression checks help narrow that margin down as all engines are different .
As I said - throttle response should be very crisp and sensitive . Main circuit should be the same under a load - if seems to take a long time to accelerate , say from 35-55mph in 4th gear it's probably too rich . You can do a main circuit plug check at cruise speed by shutting the engine off without lifting off the gas pedal and hitting the clutch at the same time . Let it cool for awhile and pull #'s 2,4 & 5 . Color should be a very light tan , no ash , no black .

I set the float a bit different - I only use the top distance and allow for about 10mm of drop , it helps to limit the drop a bit more offroad .

Sounds like your distributor is worn or something is off - the timing should be rock steady at idle .

Sarge

 

[Boaf 32]

Thank you!!!

 

[Boaf 32]

I don't know, but I would guess about 1.5 mm.

Webersarge would know

Thanks...

 

[thebigredrocker]

There are two tabs for adjusting the float - one rides on the float valve itself and the other bottoms against the outside of the valve assembly to limit drop . I usually set the top height first (fuel level in bowl) and then set the drop to around 4-5mm of travel at the valve itself . Those nitrofil floats are nice but the frames can be tweaked badly - from the factory stamping in Spain . Italian units never used that float , brass only and their frames were more consistent .
Hence, you have to take the settings with a grain of salt since there is no window to verify fuel level . Sometimes it's best to set it to factory spec and test the carb - if there is an issue you adjust it up or down a few mm to see if makes a positive improvement .

What do you have for a fuel system at this time ? The return line is very important - due to the design of the Weber's float valve and float frame there isn't a lot of leverage against that needle valve by design - this is why they recommend 3psi . Unless it's a high-performance engine I'd recommend using a return line in 8mm or 5/16" , 1/4" is also acceptable . Without a return you'll fight with it's fuel pressure issues . Regulators make this issue worse as they are a variable and not consistent enough for tests .

Get rid of those big jets , your washing down the cylinder walls/rings and can damage the engine quickly . 150 should be the biggest main jet , with your compression numbers I'd say 140-145 is more likely .

I'll be gone tomorrow most of the day and Wednesday may be out as well . After that , all is good .
Sarge