2f Aisin Carb questions. (1 Viewer)

[Vossie]

Hi all, sorry for start of new thread but couldn't find anything on search and I had this posted on my last thread but have had no response and I need to know bc I want to get this done and the engine running this afternoon .

So the 2F doesn't want to idle with out the choke on.
Fires right up no probelm with the choke on, and idles well but very high with the choke all the way out. I can push the choke in a tiny bit and she still idles well, but the second I try to push the choke in any further she dies.

Revs fine tho with choke in or out, just no idle.

Any ideas?

Also, when I put the carb back on, the spacer where I assume the egr would go on a us spec cruiser doesn't have a hole in line with the vacuum port that runs vertically between the 2 barrels of the carb. Should it have a hole there?

 

[4Cruisers]

I think it could be a problem with the idle solenoid on the carburetor. Do a search on the forum to see how to check its function. I had a similar problem with the 2F in my '71 FJ40 - I had to wire it to the positive terminal on the coil to keep it open any time the engine was on. I should get around to the correct fix one of these days.

 

[Vossie]

I think it could be a problem with the idle solenoid on the carburetor. Do a search on the forum to see how to check its function. I had a similar problem with the 2F in my '71 FJ40 - I had to wire it to the positive terminal on the coil to keep it open any time the engine was on. I should get around to the correct fix one of these days.

I've checked this. Did as you have done, have a new wire that goes from my fuse box to the idle solinoid so that I have 12v when ignition is on. And there is an audible click when I turn the key so I think the solinoid is ok.

 

[aljollano]

Yes. You can test it by jumping it to the positive side on your battery. It will click if is good.

A.J

 

[Pin_Head]

It is either a lack of idle fuel or a manifold vacuum leak. The idle fuel passages may be clogged. You could try removing the idle solenoid and idle mixture screw and blowing out the passages with compressed air.

The insulator you show is for the base of the carb between the carb and the manifold. No hole is required. It is not an EGR connection in the US.

 

[Vossie]

It is either a lack of idle fuel or a manifold vacuum leak.

I dont think its this. whilst idling with choke on i sprayed some water over where the manifold hits the head and then around the base of the carb. no sign of air coming or going around these areas. all vacuum lines are hooked up to where they need to be too. maybe im missing something though?

The idle fuel passages may be clogged. You could try removing the idle solenoid and idle mixture screw and blowing out the passages with compressed air.

The insulator you show is for the base of the carb between the carb and the manifold. No hole is required. It is not an EGR connection in the US.

ok cool, was just a thought. i have taken the carb off the engine again and am going to clean it, again. this time im going to be much more thorough in checking all the galleries.

thanks

 

[LAMBCRUSHER]

there is a screw you can use to set the high choke idle speed- turn this down so your choke out speed is around 1100 rpm. let the engine cool down, then fire it up and choke the airhorn out with a welding gloved hand-no glove could leave burns if it backfires...if the engine dies with the airhorn choked, you likely do not have an intake leak. if it keeps on chugging, you probably have an intake leak. check things like PCV are oriented correctly and any VTVs and VCVs in the lines test as GOOD and without internal/external air intrusion...check brake booster...

 

[honk]

The idle stop solenoid is certainly a known possible problem but simply verifying that it works (clicks) may not be enough to rest easy about the idle circuitry in the carb.

Bit's of flotsam - anything lodged within the passages which control/supply idle fuel can and will disrupt or block the flow of fuel to the small outlet just at or below the throttle plate.

To try to rectify the problem strong jets of air, compressed can spray of carb cleaner, or the last resort and often most effective passage of a length of appropriately sized nylon line (fishing line/fishgut) through the assorted passages can be effective in dislodging whatever has taken residence within the carb.

This has been addressed many times in this forum, several times within the last few weeks alone. A competent search will reveal innumerable repetitions of what has been said here as well as links to expert video instruction in six parts and other video information directly to the topic.

 

[Vossie]

there is a screw you can use to set the high choke idle speed- turn this down so your choke out speed is around 1100 rpm. let the engine cool down, then fire it up and choke the airhorn out with a welding gloved hand-no glove could leave burns if it backfires...if the engine dies with the airhorn choked, you likely do not have an intake leak. if it keeps on chugging, you probably have an intake leak. check things like PCV are oriented correctly and any VTVs and VCVs in the lines test as GOOD and without internal/external air intrusion...check brake booster...

Ok cool. Will try this. Like I said, Fairly certain I don't have a vacuum leak but I guess you just never know.

What are the VTVS and VCVS and PCV? Sorry, petrol newbie here

The idle stop solenoid is certainly a known possible problem but simply verifying that it works (clicks) may not be enough to rest easy about the idle circuitry in the carb.

Bit's of flotsam - anything lodged within the passages which control/supply idle fuel can and will disrupt or block the flow of fuel to the small outlet just at or below the throttle plate.

To try to rectify the problem strong jets of air, compressed can spray of carb cleaner, or the last resort and often most effective passage of a length of appropriately sized nylon line (fishing line/fishgut) through the assorted passages can be effective in dislodging whatever has taken residence within the carb.

This has been addressed many times in this forum, several times within the last few weeks alone. A competent search will reveal innumerable repetitions of what has been said here as well as links to expert video instruction in six parts and other video information directly to the topic.

Ok, great info thanks. On that "there maybe more to the idle solinoid other than clicking", are there any checks other than seeing that the solinoid actually functions to see if fuel is getting past there?

Also, the very first thing I did was search. I don't like starting threads for nothing, but I have already taken this carb apart, twice, using @Pin_Head s you tube videos, which are fantastic, and I still come up with this problem, so felt the need to get some advice directly on what I am currently facing.

Thanks for all the info.

 

[Pin_Head]

Adjust the idle speed and mix until it will just barely run. Try spraying carb cleaner or propane gas around the manifold gaskets, especially underneath and see if the idle speeds up. Check the manifold for cracks underneath the carb and check all manifold vacuum connections like the power brake booster and the PCV inlet.

 

[honk]

The best thing would be to have a copy of the 2F engine factory repair manual. I THINK someone here has it available to download in pdf form. This post might bring out a link for you.

In that manual, section on fuel systems, are diagrams which show the internal passageways within the Aisin carb, both US and non-US versions which are quite similar insofar as idle circuitry is concerned.

Basically fuel is taken from the float bowl through thee first main jet into a passage which leads up through the first slow jet (one of those which screw into the carb float body) on to and past the interrupting idle stop solenoid and then down into a small chamber containing the adjusting portion of the idle mixture screw and then out into the primary airflow via a very small hole which exits at the carb primary throttle plate.

It's those passages through which I'd say you need to physically pass sections of nylon monofilament line (abovementioned fishgut ).
It sounds like you've tried most everything else.

A continued failure might mean it's time to cut your losses by starting again rebuilding a different carb. Sometimes there are mysteries in this stuff in which all the right answers are nevertheless unhelpful.

 

[handcannon]

There is one more area to check for a vacuum leak that I don't think I remember you saying was checked. That happens to be the intake manifold, directly under the carb. This is the manifold area that is between the intake and exhaust manifolds, and not accessible from anywhere on the outside of the manifold. This area is known for getting cracks in it and causing a vacuum leak. It is an area easily missed, and difficult to see.

Don

 

[Vossie]

ok, right. so i have redone the carb, AGAIN, according to @Pin_Head s videos. all the galleries are clear and everything is as it should be.

i also check, im not losing vacuum at the booster or anywhere else. i checked the side of the head where the manifold bolts on, again, no vacuum leak there either. and as far as i can tell there is no leak inside the manifold between the intake and exhaust.

the only thing i noticed is that i do have a leak between my exhaust manifold and where the exhaust pipe bolts to it. there is quite a lot of blow out there. but could this have a any effect on the running of the engine??

she still starts up fine on choke out. runs fine. idles fine. revs fine. but the second you even think of pushing the choke in, she dies.

 

[Pin_Head]

You need to let it warm up before you push in the choke. Any chance it is cold where you are at? If so, the flapper valve in the exhaust manifold should be working to help the carb warm up faster.

The exhaust leak makes an annoying noise, but it is not related to your carb problems.

Any chance that the primary main jet is partially clogged with a piece of dirt? I have been fooled by a piece that was stuck inside and I needed a magnifying glass to see it.

 

[JAFO2014]

With it idling ( I guess you have to choke it, so hard to see I guess), is gas spewing out the venturi on the passenger side? Maybe you can back the choke out enough to see in the top of the carb. You should not see gas there when at idle. The gas should be getting to the intake via the idle circuit, which dumps the gas out below the butterfly at the bottom. If you see gas being dumped out the venturi during idle then the idle circuit is blocked some place.

In troubleshooting mine I traced the path of the idle circuit. Saw where the passages lead to the fuel cut solenoid. I energized the solenoid and then blew carb cleaner through the passage at one end and verified the cleaner spit out the hole that leads to the bottom section of the carb. This will verify that the fuel cut solenoid is opening.

I had an idle problem that sounds like yours and I ended up finding a piece of crud in the bottom section of the carb that was blocking the idle circuit. If you have the carb off, take off the top. Now remove the idle mix screw from the base and blow compressed air into that hole. This should force air out a hole in the bottom section of the carb that leads up to the top section of the carb, leading to the fuel cut solenoid passage. Make sure the idle circuit passage that leads up to the top of the carb is clear. That way you know that the gas coming from the fuel cut solenoid is getting all the way down.

And trace it through the bottom part of the carb where it leaves the bowl in the first place. It leaves the bowl through a passage, then goes through a jet and up into the top of the carb. Make sure that jet is clean. Once mine had the jet clogged and would not idle.

The gas being supplied for idle leaves the bowl through a passage, through a jet in the bottom part of the carb and then up to the top of the carb where it goes through the fuel cut solenoid. Then through another passage and down to the bottom of the carb on the passenger side where it gets metered by the idle mix screw and dumped out and goes to the intake.

 

[Vossie]

You need to let it warm up before you push in the choke. Any chance it is cold where you are at? If so, the flapper valve in the exhaust manifold should be working to help the carb warm up faster.

The exhaust leak makes an annoying noise, but it is not related to your carb problems.

Any chance that the primary main jet is partially clogged with a piece of dirt? I have been fooled by a piece that was stuck inside and I needed a magnifying glass to see it.

It's 35 deg C here so, I don't think it being cold is a major thing. I did let the engine get warm as well when I last checked but still no dive.

I just cleaned all the jets. Made sure everything was spotless. Unless something got in after reassembly. Is there a way to check once the carb is back together that all the jets and passageways are clean?

With it idling ( I guess you have to choke it, so hard to see I guess), is gas spewing out the venturi on the passenger side? Maybe you can back the choke out enough to see in the top of the carb. You should not see gas there when at idle. The gas should be getting to the intake via the idle circuit, which dumps the gas out below the butterfly at the bottom. If you see gas being dumped out the venturi during idle then the idle circuit is blocked some place.

In troubleshooting mine I traced the path of the idle circuit. Saw where the passages lead to the fuel cut solenoid. I energized the solenoid and then blew carb cleaner through the passage at one end and verified the cleaner spit out the hole that leads to the bottom section of the carb. This will verify that the fuel cut solenoid is opening.

I had an idle problem that sounds like yours and I ended up finding a piece of crud in the bottom section of the carb that was blocking the idle circuit. If you have the carb off, take off the top. Now remove the idle mix screw from the base and blow compressed air into that hole. This should force air out a hole in the bottom section of the carb that leads up to the top section of the carb, leading to the fuel cut solenoid passage. Make sure the idle circuit passage that leads up to the top of the carb is clear. That way you know that the gas coming from the fuel cut solenoid is getting all the way down.

And trace it through the bottom part of the carb where it leaves the bowl in the first place. It leaves the bowl through a passage, then goes through a jet and up into the top of the carb. Make sure that jet is clean. Once mine had the jet clogged and would not idle.

The gas being supplied for idle leaves the bowl through a passage, through a jet in the bottom part of the carb and then up to the top of the carb where it goes through the fuel cut solenoid. Then through another passage and down to the bottom of the carb on the passenger side where it gets metered by the idle mix screw and dumped out and goes to the intake.

During and after reassembly of the carb I did pretty much that, traced all the passageways of the idle circuit and passed fishing wire through them and then blew them out with carb cleaner... still the same issue.

I will check to see if I can see fuel coming out the venturi. But I'm pretty sure the idle passageways are clean.

Can these be checked whilst the carb is on?

 

[Pin_Head]

You can't really check them thoroghly with the carb assembled. You can check if any idle fuel is getting delivered.
Adjust the idle speed and idle mixture until the engine barely runs (with the choke off). Then disconnect the idle fuel solenoid and see if it stalls. If so some fuel is getting there.

 

[Vossie]

You can't really check them thoroghly with the carb assembled. You can check if any idle fuel is getting delivered.
Adjust the idle speed and idle mixture until the engine barely runs (with the choke off). Then disconnect the idle fuel solenoid and see if it stalls. If so some fuel is getting there.

Ok, but there in lies the problem, how can I check that of I need to have the choke off, when the engine stalls straight away when you try to put the choke off?

Sorry of I'm being dense about this, but am I missing something?

 

[honk]

My apologies. I see that you never received a followup answer to your : "Ok, great info thanks. On that "there maybe more to the idle solinoid other than clicking", are there any checks other than seeing that the solinoid actually functions to see if fuel is getting past there?", and so, belatedly,

Have you had the idle stop solenoid off the carb to operate it in your hand by applying 12v dc to the wire lead with the body of the solenoid grounded? (This isn't difficult. If the wire is long enough that the solenoid can be stretched across a battery, wire to positive/body to ground. Otherwise a jumper wire to extend the wire for testing).

If so, did it work? A somewhat resounding 'click' noise; small diameter brass rod moving in/out as solenoid is energized and released; tiny o-ring around brass rod end fixture? (not all have the o-ring, I think). Is the small rod straight, clean, and seem to move smoothly?

You can do these things without removing the carb from the manifold, again.

 

[Vossie]

My apologies. I see that you never received a followup answer to your : "Ok, great info thanks. On that "there maybe more to the idle solinoid other than clicking", are there any checks other than seeing that the solinoid actually functions to see if fuel is getting past there?", and so, belatedly,

Have you had the idle stop solenoid off the carb to operate it in your hand by applying 12v dc to the wire lead with the body of the solenoid grounded? (This isn't difficult. If the wire is long enough that the solenoid can be stretched across a battery, wire to positive/body to ground. Otherwise a jumper wire to extend the wire for testing).

If so, did it work? A somewhat resounding 'click' noise; small diameter brass rod moving in/out as solenoid is energized and released; tiny o-ring around brass rod end fixture? (not all have the o-ring, I think). Is the small rod straight, clean, and seem to move smoothly?

You can do these things without removing the carb from the manifold, again.

Ja, I have done that. It fires when hooked up to 12v. Audible click and can feel it actuate. But it was very difficult to see if the brass rod moves inside or not... it feels like it does. I couldn't see bc it has a sort of seize around it