Franken-radiator is installed! Rig turned over! Sputters out when I add throttle:( (1 Viewer)

[jdog35]

Idle sounds great, and runs consistently. I searched the FAQ and think it might be one of two things:

Gunky fuel-filter
Not enough gas in the tank

The first one is obvious, and I'll check today. The second one I recalled seeing in a thread (somewhere at some point DEEP into a search. The person said they were having fuel-starvation issues when their tank was lower than 1/3 full (or something like that). I know I have about 2 or 3 gallons in the tank right now, as I've kept it relatively empty/low during all the work without the rig running.

Does that option make any sense as to the possible cause? I don't THINK it's a vacuum issue as I can add a little throttle above idle and keep the engine running...but anything in the 2000rpm range it's starts choking/stuttering out.

I hope that makes sense. I can post some pictures if it would help. If anyone else has other thoughts on something I should check as well, I'm all ears!

Thank y'all!

 

[rsbcruiser]

It can't hurt to replace the fuel filter. If the rig has sat for awhile then there could be gunk in the trunk. ;p

You don't say what kind of carb you have. Is it original? If so then take a look at the sight glass for your fuel level in the bowl.
The carb jets might be all clogged up too.

Another one is you might be having venting issues with the tank, developing a vacuum. That sucks.

Doubt it is the fuel level in the tank but it could be bad gas if it has sat in there for a bit. The problem with those tanks is the groove across the bottom for the tire carrier. It deprives the fuel outtake of a couple gallons when on the level or uphill. One other problem is that the fuel tank internal vent lines might be gunked up.

 

[jdog35]

Thanks rsb. The float level is perfect at half-way up (or down depending on your take the glass on the carb. It is a stock Asani carb on there too by the way.

The gas has been in, after I fully drained and cleaned the fuel tank, for about a week or two at most. I started thinking this morning I may have just burned through a couple gallons while playing with all the idle adjustments. I didn't really clock how long I kept the rig running, just sort of kept working you know.

I'm double-checking the fuel filter tonight, and then I'll go about looking at the venting issue I think. It's about the only thing that could have changed with all my fiddling around (considering I didn't have this issue before replacing the radiator...which obviously wouldn't have effected the carb/fuel-issue I'm having now).

Thanks again!

 

[jdog35]

Okay...so...ruled out the fuel filter (shiny new clean one installed). The float level is still looking good at idle. I'm getting fuel into the carb (obviously) through the interior inlets, but the two big jets at the top of the bowl are not flowing. As in...NOTHING is coming out when I apply throttle. That definitely didn't happen prior to the rebuild.

My gut would tell me something was reassembled incorrectly in the carb, thus prohibiting the main jets from distributing fuel. They worked prior to carb refresh (flowed like friggin' garden hoses!).

I do recall seeing a thread that referenced placing a slip of cardboard on top of the carb to determine if there was a vacuum issue. When I do this, it bogs down completely and shuts down. I don't recall specifically in that thread if that meant there was a vacuum issue or not though Too much reading is all blending together now. Need to start bookmarking more pages.

Anyway, thanks for the input thus far, and for those to come! It is MOST appreciated!

 

[LAMBCRUSHER]

Oklahoma rebuild.... that's what it is called around here when you choke out the carb at high idle. This pulls the crud and junk thru the ports and jets and sometimes hopefully unclogs them. IIRC the fact that it bogs and dies out is a sign that there are not any serious vacuum leaks. Is there vacuum at the power valve? How about the idle solenoid? I have read that if the idle solenoid isn't working, you can pull too much fuel thru the main circuit at idle. Also if the power valve does not have vacuum at idle you could just be dumping in too much fuel and flooding out. Just some thoughts, hope it helps.

 

[jdog35]

Franken-radiator pics as promised...a while ago

 

[jdog35]

And the subsequent radiator pic. I've ruled out vacuum issues, and the fuel pump is working fine. The only thing I can determine is there is absolutely no fuel coming out through the jets into the bowls once I hit the throttle. So, either the guy who rebuilt the carb re-assembled something wrong, or there's an adjustment screw (or multiple) that need to be tweaked. Any thoughts would be MOST appreciated! Thanks guys!

 

[LAMBCRUSHER]

A service manual would be helpful to you. If it was not adjusted upon installation, you may need to go thru it step by step. There are three screw to adjust the idle mix, idle speed and throttle positioner. There are also adjustments to be made to the accelerator pump arm, which is responsible for adding that extra squirt of fuel at take off. Have you checked the power valve to see if it is getting vacuum at idle? The Rad looks good, BTW. Is that just a 40 series radiator?

 

[jdog35]

Thanks Lamb. I have 3 different manuals that I've been pouring through, but since I'm not 100% certain what I'm looking for always, makes it a little difficult

I'm thinking that some of the issue has to do with the throttle assembly too. I have yet to find a good picture of what the throttle linkage looks like fully installed. I THINK I have it right, but when I push the throttle, there is no movement in the diaphragm linked to the circled arm.

I'm not sure if you can determine from the photo, but the photo with the throttle linkage assembly was the best I could determine of how it goes together. Does anything look goofy to you?

And yeah that's a replacement 40-series radiator. My original needed to be rebuilt, but I snagged this one for more than half-off what a rebuild would have been. A little fabricating time is worth saving a couple hundred you know?

 

[Pighead]

Could be your vacuum secondary isn't working...
Or your jets are wrong/switched...
Or your dizzy isn't advancing...
If your fuel is at the halfway point in the porthole, and stays there even when the engine sputters, you can pretty much rule out a fuel delivery issue.

 

[LAMBCRUSHER]

The secondary is opened by internal vacuum, I thought. You will not be able to get it to open just by hitting the linkage. Pighead has another good thought. Are the primary and secondary jets reversed? One is considerably larger than the other, which would make the air fuel mixture off. I have a haynes manual-many here swear it is junk- I have resevations when using it. Knowing that there ARE some discrepancies betwwen the FACTORY service manual and the haynes, I do multi layered research. I have found the haynes to be ok for carb adjustment tech, and spot on for the electrical diagrams-when compared to the toyota electrical suppliment. There are some threads in the 40-45,55 series tech pages, that describe a lean drop adjustment method. As much of a pain in the rear as it can be, it is not too bad to remove the air horn on these carbs and check the jet size/port location, float level and whatnot. I'd recommend cracking that thing open and verifying these things first. If they are not in the right ports, you will never adjust it correctly. Also check the power valve to make sure it is there. Once you know what the insides are doing, you can go back to the adjustment screws and linkages. IIRC the secondary jet should be smaller( correction Please!!!) than the primary. On the outside of the carb, there are screws for idle speed(throttle stop)idle mixture(screw to inside of carb when mounted-between the carb and the manifold) I'd start w/ the mix screw out about 3 turns from just barely seated(screwed all the way in) idle speed about one turn in from fully backed out. You will need to have you timing set correctly first(7*btdc), fire up the engine and turn the idle speed up(in) to where the engine will try to stay running on its own (slowly tho). next slowly turn the mixture screw out to reach a fast idle. Then turn the idle speed screw in or out to obtain 650-700 rpms. Then turn the mixture screw in slowly till the rpms JUST drop off(lean drop method)and then adjust the speed screw to get back to idle speed. Just a quick rough, it is early and you should verify a couple of these things first- i prolly missed something HTH Good luck!

 

[LAMBCRUSHER]

In the first pic (of that battery of three of you carb), I cannot tell if you idle solenoid has a wire going to it. If there is not twelve volts going to that solenoid on the top rear of the carb, it will not idle- or at least very well.....if the solenoid isn't working(audible click heard when the voltage reaches the solenoid, then the carb CAN pull its idle gasses thru the main circuit rather than the idle circuit, this will make for an overly rich idle mix- and can cause POOR idle quality at best.....

 

[Pighead]

IIRC the secondary jet should be smaller( correction Please!!!) than the primary.

Nope. Secondary jet is traditionally larger than the primary jet...

 

[LAMBCRUSHER]

Thank You, Sir!