Trouble starting 1975 Fj40 (1 Viewer)

[Aloha Jen]

I was hoping to get some advice/guidance on a starting problem I am having on my 1975 Fj40. It has a 2f engine and a desmoged carburetor from a 1978 fj40.

It idles, revs with little to no hesitation and drives great! However, whenever I try and start it cold or after it is plenty warmed up, it really struggles to start. Meaning it cranks or turns over a lot of times before the engine starts up. Here is a video of a fairly typical start:



It’s weird because it doesn’t always take this long to start, kind of happens randomly. But more often then not, it’s starts like this. Here is video of it running after it starts. It idles smoothly and drives great from low speeds up to 58 mph on the freeway.



And an internal carburetor view after a fairly quick start. Carb is from a 1978 fj40

1975 Fj40 (1978 carburetor) Carburetor view - https://youtube.com/shorts/_8M4VEVvUbI?si=f8KW-q55RzIOHN7z

One thing to note is that my distributor is one of the HEI or DUI variety, and seems to work just fine when driving. Here is a photo of it, it’s an old photo before it was hooked up, but you get the idea of what it is.

Also one more thing to mention, the gas fill line in the little carb window seems to be either right above the middle or nearly to the top of the little window.

Just wondering if some of you had some words of wisdom or is if you have a similar problem that you found a solution for. Thanks!

 

[mattressking]

Struggle to start is an issue with air/fuel, which means a number of items need to be checked. Also noting 'little to no hesitation' sounds like there is a hesitation. Initial list to find out:

1. What is vacuum reading at idle (cold & hot).
2. What is timing set at?
3. Fuel level is fine for now if you are on flat ground, ideally you want it about the middle, but the idea there is to prevent overflowing and flooding the venturis especially for off-camber/steep grade scenarios....so at some point, get that adjusted so it stays in the middle.
4. What plugs and what are they gapped to?
5. What color/condition are your spark plugs?
6. When was the last time the carb was checked over correctly? All of the jets and circuits need to be inspected and verified the correct sizes are installed.
7. Is your choke hooked up/functioning?
8. What vacuum items are currently connected; which contributes to item 1.

 

[charliemeyer007]

Take the cap off the distributor, look at the contacts, if they are aluminum there can be a band of oxidation that builds up quickly where the rotor passes by - scrape it off carefully - as its an insulator ( I like brass contacts, but even those will corrode eventually) Small blade on the swiss army knife is my scraper of choice. Also check the contacts in the cap and the plug ends of the wires.

 

[Aloha Jen]

Struggle to start is an issue with air/fuel, which means a number of items need to be checked. Also noting 'little to no hesitation' sounds like there is a hesitation. Initial list to find out:

1. What is vacuum reading at idle (cold & hot).
2. What is timing set at?
3. Fuel level is fine for now if you are on flat ground, ideally you want it about the middle, but the idea there is to prevent overflowing and flooding the venturis especially for off-camber/steep grade scenarios....so at some point, get that adjusted so it stays in the middle.
4. What plugs and what are they gapped to?
5. What color/condition are your spark plugs?
6. When was the last time the carb was checked over correctly? All of the jets and circuits need to be inspected and verified the correct sizes are installed.
7. Is your choke hooked up/functioning?
8. What vacuum items are currently connected; which contributes to item 1.

Sorry, should have said no hesitation, I guess I was more comparing to my more modern fuel injected LCs. That is a lot of stuff to get to in you list, and will look into the things you mentioned. One question I have is, when it finally starts and is idling and driving really good, wouldn’t that mean that the timing is good, plugs are gapped correctly (also new spark plugs), and Carb is operating correctly? It honestly drives really well after the long start.

Also Choke is hooked up and working properly. The long starts happen with or without the choke engaged or whether the engine is hot or cold.

 

[CondeCruiser]

The boot on the carb plunger looks kind of rough. I'm assuming it has not been rebuilt?

 

[mattressking]

Sorry, should have said no hesitation, I guess I was more comparing to my more modern fuel injected LCs. That is a lot of stuff to get to in you list, and will look into the things you mentioned. One question I have is, when it finally starts and is idling and driving really good, wouldn’t that mean that the timing is good, plugs are gapped correctly (also new spark plugs), and Carb is operating correctly? It honestly drives really well after the long start.

No

Also Choke is hooked up and working properly. The long starts happen with or without the choke engaged or whether the engine is hot or cold.

If you have trouble starting hot or cold, that means mixture is a mess (which means vacuum could be one or all of the culprit) . How many times are you pumping the pedal to start? Also note, everyones comparison of 'runs well' is quite startling sometimes, so without knowing vacuum at idle, it is hard to say how good it is actually running.

The truck shouldn't drive 'differently' to a fuel injected vehicle in regards to smoothness. The difference is that FI takes out the choke requirement, primes the fuel system for cold starts/after long periods of sitting and adjusting for weather/temperature/pressure changes, actual transition from primary to secondary for example all will be smooth as well as on/off/part throttle.

The items listed are a quick grab, it's just a baseline for understanding. Vacuum is the biggest.

Have you done a lean drop/inspected the mixture screw, confirmed correct jetting? There is a lot at play here and no one single culprit, especially since you can't scan codes.

 

[fjwagon]

If did not know any better, I think for me the first reaction is this Land Cruiser has not been started for weeks. But I'm sure that is not the case. On my 40, normally it will turn maybe once before it starts and in between starts it will start easily. Yours almost feels like starving for fuel, you are in verge of flooding it or not getting spark form the coil. But I'm noticing the carb's sight glass says you are getting too much fuel. And of course you get spark since starts. Does it do the same thing when you remove the air filter while try to start. I would replace the fuel filter if you have not already done so and confirm the fuel has good flow(check fuel lines) I do not suspect the fuel pump...or least not yet. You may consider adding some seafoam to to gas tank.

 

[Aloha Jen]

Take the cap off the distributor, look at the contacts, if they are aluminum there can be a band of oxidation that builds up quickly where the rotor passes by - scrape it off carefully - as its an insulator ( I like brass contacts, but even those will corrode eventually) Small blade on the swiss army knife is my scraper of choice. Also check the contacts in the cap and the plug ends of the wires.

Thanks, I will check under the cap to see if there is any corrosion.

 

[franklin40]

No


If you have trouble starting hot or cold, that means mixture is a mess (which means vacuum could be one or all of the culprit) . How many times are you pumping the pedal to start? Also note, everyones comparison of 'runs well' is quite startling sometimes, so without knowing vacuum at idle, it is hard to say how good it is actually running.

The truck shouldn't drive 'differently' to a fuel injected vehicle in regards to smoothness. The difference is that FI takes out the choke requirement, primes the fuel system for cold starts/after long periods of sitting and adjusting for weather/temperature/pressure changes, actual transition from primary to secondary for example all will be smooth as well as on/off/part throttle.

The items listed are a quick grab, it's just a baseline for understanding. Vacuum is the biggest.

Have you done a lean drop/inspected the mixture screw, confirmed correct jetting? There is a lot at play here and no one single culprit, especially since you can't scan codes.

it’s amazing how well a carb with a vacuum leak can still run but will have funny symptoms when idling. i had a brake booster leak that i could audibly hear and my engine ran fine because i tuned it with the leak (unknowingly). when i fixed the problem my idle issues went away and my mileage improved 10% but when at highway speeds i’d never have know there was a problem. vacuum can be a little bugger with carbs for sure

 

[Aloha Jen]

No


If you have trouble starting hot or cold, that means mixture is a mess (which means vacuum could be one or all of the culprit) . How many times are you pumping the pedal to start? Also note, everyones comparison of 'runs well' is quite startling sometimes, so without knowing vacuum at idle, it is hard to say how good it is actually running.

The truck shouldn't drive 'differently' to a fuel injected vehicle in regards to smoothness. The difference is that FI takes out the choke requirement, primes the fuel system for cold starts/after long periods of sitting and adjusting for weather/temperature/pressure changes, actual transition from primary to secondary for example all will be smooth as well as on/off/part throttle.

The items listed are a quick grab, it's just a baseline for understanding. Vacuum is the biggest.

Have you done a lean drop/inspected the mixture screw, confirmed correct jetting? There is a lot at play here and no one single culprit, especially since you can't scan codes.

Ok, I will start with checking the vacuum when the engine is cold and hot to see if that is the issue.

Have not checked lean drop or mixture screw yet, but will research a bit on how to do that. I understand that people’s opinion on what’s running good varies a lot, but up until last week it was starting right up and running and idling great, so just trying to diagnose what’s happening. I really appreciate all the advice.

 

[Skreddy]

I agree that you could have vac leak and/or mixture issues. One free thing to try before tearing in is: before attempting to start, check where the fuel is in the sight glass. If it’s halfway or more, when you try to crank it, don’t give any choke and floor the pedal before cranking. No pumps, just floor it and keep it there while cranking. If it doesn’t start within 3 seconds, then disregard. With my cruisers, especially in warmer temps, I’ve found about 1/3 up the sight glass is plenty or they can start to pull fuel outside of the idle circuit. So if you’re over half full and flooring it with no choke helps, you could be pulling too much fuel at idle for startup.

Disclaimer: better carb folk than me have already chimed in so take my advice at less than the price paid….

 

[Aloha Jen]

I agree that you could have vac leak and/or mixture issues. One free thing to try before tearing in is: before attempting to start, check where the fuel is in the sight glass. If it’s halfway or more, when you try to crank it, don’t give any choke and floor the pedal before cranking. No pumps, just floor it and keep it there while cranking. If it doesn’t start within 3 seconds, then disregard. With my cruisers, especially in warmer temps, I’ve found about 1/3 up the sight glass is plenty or they can start to pull fuel outside of the idle circuit. So if you’re over half full and flooring it with no choke helps, you could be pulling too much fuel at idle for startup.

Disclaimer: better carb folk than me have already chimed in so take my advice at less than the price paid….

The sight glass does regularly show the level to be above the middle or even toward the top. I dont excessively pump the gas pedal before starting or use the choke. Si the sight glass level is filling up from some other problem. Do you know what causes it to pull too much fuel into that sight glass chamber?

 

[Skreddy]

The sight glass does regularly show the level to be above the middle or even toward the top. I dont excessively pump the gas pedal before starting or use the choke. Si the sight glass level is filling up from some other problem. Do you know what causes it to pull too much fuel into that sight glass chamber?

The adjustment of the float level will determine how high the fuel fills that bowl.

 

[Aloha Jen]

If did not know any better, I think for me the first reaction is this Land Cruiser has not been started for weeks. But I'm sure that is not the case. On my 40, normally it will turn maybe once before it starts and in between starts it will start easily. Yours almost feels like starving for fuel, you are in verge of flooding it or not getting spark form the coil. But I'm noticing the carb's sight glass says you are getting too much fuel. And of course you get spark since starts. Does it do the same thing when you remove the air filter while try to start. I would replace the fuel filter if you have not already done so and confirm the fuel has good flow(check fuel lines) I do not suspect the fuel pump...or least not yet. You may consider adding some seafoam to to gas tank.

Yes, it does the same long start if the air filter housing is on or off. It has a brand new OEM fuel filter and new rubber fuel lines that were just installed a couple weeks ago.

Fuel pump seems to be working, at least when it starts and while driving. But you are correct that the carbs sight glass shows that the level is nearly always above the mid point or towards the top. But it reaches those levels without me pumping the gas pedal or using the choke, so something seems to be making it overfilling and causing it to react like it is flooded.

 

[Aloha Jen]

The boot on the carb plunger looks kind of rough. I'm assuming it has not been rebuilt?

Correct, carb has not been rebuilt, at least since I have owned it. It appears to have rebuilt in the past and was desmogues, but the boot does seem a little busted looking.

 

[fjwagon]

You take the top off the carb and see if the float is still functioning like it supposed.

Also make sure you don't have leaks on your hoses. You can use soapy spray bottle if you suspect you have bad connection at carb.

There is vendor here on mud that sells carbs, I forget who...maybe Troll....something. And there are also several vendors that will rebuild your carb.

 

[Aloha Jen]

The items listed are a quick grab, it's just a baseline for understanding. Vacuum is the biggest.

I just tested the vacuum. It’s my first time using one and it is a brand new gauge…so I’m not entirely sure how to read it. I checked the FSM and couldn’t find anywhere what the appropriate vacuum gauge reading should be, but here it is at idle upon start up when the engine was cold.

Here it is a bit later when the temp gauge on my dash was at its normal position when warmed up.

Connected the gauge with a T fitting that went between the vacuum line that connects a small metal tube coming off the manifold and runs to a metal tube that comes from the circular shaped part near the top of the carb. Sorry if I am butchering the names of all of these, but carbs are very foreign to me. But that seems to be the only vacuum line going into the carb. The photo should help explain where I connected the T fitting for the gauge. How do those vacuum reading look?

 

[middlecalf]

Vacuum reading is exceptional, 21-22 inHg. Any flicker in the needle?

This issue just started happening, a week or so ago? Ran/started fine before that?

 

[Aloha Jen]

Vacuum reading is exceptional, 21-22 inHg. Any flicker in the needle?

This issue just started happening, a week or so ago? Ran/started fine before that?

Needle is still, no flicker.

Yes, the extra long starts just started 4 days ago. Was happening warm or cold, but occasionally started right up over the last few days. I just went on a quick errand to the store and it started after one crank. When I came out, started right up again. It’s so frustrating to try and fix a problem that isn’t consistent.

 

[Aloha Jen]

You may consider adding some seafoam to to gas tank.

I’m not familiar with what Seafoam does, but will try it if you think it would help.