carb problem on a 1980 720 l20b

[ggzilla]

1973 came with smaller engine. The Carb may work well as they are jetted richer than the newer emissions carbs.

[Lowandslow]

I installed the carb today and man oh man it idled beautifully!! 800 warmed up and 1600 on cold idle!! I have never seen a carb'd vehicle idle so smoothly. Unfortunately the throttle cable became frayed today so the throttle keeps getting stuck so I don't know how it accelerates and performs but we have idle and that's a lot more than my old carb did.

 

[Lowandslow]

I went to the junkyard and found no throttle cables for the l20. All the 620's and 720's had been stripped of them. The only ones I found were the later z24 throttle body cables. Are any other Datsum throttle cables interchangeable with the l20?

[Lowandslow]

*throttle cables.

 

I know they're longer but could I just have them sweep around at least for a temporary fix until mine comes in?

[ggzilla]

Longer is no problem. As long as the exposed part of the cable is the same.

 

 

And even so I've used longer exposed cable and wrapped the extra length around the accelerator pedal.

[Lowandslow]

Okay so as long as the carb end looks the same it should be alright?

[datzenmike]

It will work. The 720 is mounted vertical and the 620 horizontal on firewall or the other way round. I've used a 720 cable before. May have to loop the extra once around the carb but it can be done.

[Lowandslow]

I have a 720 but with the l20b so the z24 throttle cable will still work??

[datzenmike]

It's much longer but can be re-worked and made to work.

[Lowandslow]

Yeah it seemed a lot longer but sounds good!! Hopefully ill have the truck running tonight.

[Lowandslow]

Got it running!! It idles smoothly and the longer cable was pretty easy to re route other than adjusting the springs on the carb because it would not return it back.

 

One thing that I noticed is that I can not get full throttle. I have at best 1/2 and it hesitates on hard acceleration. Would this be because of the smaller carb? Can the full throttle just be adjusted under the pedal?

[ggzilla]

1/2 throttle is caused by a mechanical problem for example by too much slack in the cable. It is not caused by carburetor size.

[Lowandslow]

Well I have the throttle cable all the way pulled back as far as I can haha and I meant the hesitation being a result of the smaller carb

[ggzilla]

A smaller Carb will generally have better throttle response (run smoother and more responsive) but will have less high rpm full throttle power.

 

Hesitation is caused by other things. Incorrect jetting will cause it, but so will vacuum hose leaks or incorrect timing.

[Lowandslow]

Okay I will have to look into it a bit more then, its off of an l18 and its now on an l20b so I thought that'd make a difference. Ill look for some vacuum leaks and see into the jetting. The previous truck ran great so I'm wondering if its just a vacuum leak or vacuum advance not turning on because of a leak