Carb problem, even after rebuild.

[dmaddox]

Hello guys,

I have rebuilt my SD-40 to factory spec, using the F engine repair manual by Toyota.

Now, what is happening is the "C" clip that holds the lower butterfly to the accelerator pump is stretching out because for some reason it gets hard to pull down the accelerator pump.

Here:

Now, I have pulled it apart, made sure to lube the plunger (as seen in photo) with oil to ensure that both the plunger and the shaft are both clean and free of debris.

It did it again!!!! It somehow is fine but then when I run the vehicle the force of the gas pedal stretches out the clip and then what I notice is NO power off the line. It falls on it's face.

So, I put in a new plunger:

Oiled this one up too, follow instructions....

Now, I have just pulled the carb off - but I'd like to use this carb - anyone have any ideas as to why this is happening?

Thanks so much,

Dallas

 

[IDave]

Is the inside of the plunger cylinder corroded? Of course, it is the lift rod that that "C clip"/throttle connecting link actually attaches to. So, the lift rod might be hanging up in the operating block as well.
Several thoughts, anyway.

 

[rockcod]

Dallas,

Was the carb working before the rebuild? or is this a new one to you? Does it do it only when the truck is running? How about if the carb is out and operated to wide open? Did you make sure the metering rod fit into jet? When I rebuilt my carb it was a pretty tight fit at first. Just a thought, I am learning everyday with my truck.

 

[malcb]

I love the look of those carbs, the big sight glass is cool.

Don't think I can help but have to ask - any rags in there?

Simle everytime I think of the LCML eamils about that.

 

[wesintl]

It would seem the top half is working ok if that piece is stretching. Does the bottom piece with the butterfly operate smooth? the bottom piece is cast and that shaft can seize. I have that like that. I've soaked it for a year and it doesn't budge.

 

[IDave]

It would seem the top half is working ok if that piece is stretching. Does the bottom piece with the butterfly operate smooth? the bottom piece is cast and that shaft can seize. I have that like that. I've soaked it for a year and it doesn't budge.

Doesn't the throttle valve lever move the shaft with that butterfly?

I'm probably cornfuzed.

 

[wesintl]

yea it does...


Does the plunger and throttle valve move smoothly with the carb off the truck?

 

[dmaddox]

Yes, everything seems to run smooth when it's off the truck. As you see in the pictures, I just plopped it on the shelf until I could get to it. But I can pick it up as is....and everything opens and closes smoothly.

I am with you guys on the thought that something besides the plunger is hanging up. What.....I don't know becuase when I rebuilt it....evertyhing moved and looked smooth.

Dallas

PS. No shop rags, LOL.

 

[IDave]

So when you rebuilt the carb, did you replace the O-ring that fits in the tube for the lift rod? If you didn't get it in it's groove correctly, or if there are old bits of hardened old O-ring rubber in there, they could certainly cause you to hang.



Maybe you should just send me your carb and I'll check it!

 

[wesintl]

My thoughts are with rockcod... does the metering rod fit the jet? Some are tapered differently. I have to use my original tapered metering rod. the ones in the rebuild didn't work with my carb.

 

[dmaddox]

I am going to be bringing it inside to rebuild. My wife just bought 20 rhode island red chicks - so I have been busy with that project. If i recall, i simply cleaned the metering rod and jet that were previously in the carb - I dont recall replacing them.

your friend - dallas

 

[Kief]

Does it move freely without fuel vs. with fuel or is there any difference? No flow out means no go if that is the case.

 

[IDave]

Does it move freely without fuel vs. with fuel or is there any difference? No flow out means no go if that is the case.

That's a good point. I suppose if the chamber was filled with fuel and the accelerating circuit passage (or check ball valve or pump jet) was plugged (hard to clean because of angles)....