In March, a 16 year old driver in his uncle's car, on his learners' permit, with a 15 year old and a 17 year old, neither of which had licenses, ran a stop sign and crossed a 4-lane divided-highway in Millen Georgia. My mother-in-law and my wife were passengers in the car I was driving. I t-boned their car at about 35 MPH. Airbags taste, smell, and feel horrible .... but much better than steering wheels and dashes and windshields I guess ... Our ONLY car, a 2001 Mitsubishi Mirage was totaled and insurance STILL has not caught up.

I was basically given an '81 F100, by a friend who knows we have nothing, right now. It has a reman inline-6 in it. No one seems to know anything about the engine, other than "it has about 20k miles on it." It has issues, and I need help ......

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Ok, here goes ::winces::

I am a noob when it comes to car engines. I'm 34. I grew up around my Dad and older brother always fixing engines, so I know more than the average noob, but I have little experience of my own.

I have some experience on smaller engines, tractors, lawnmowers, etc. Please go easy on me...
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I can not find a number plate on the engine.. I've looked. Exhaust and intake are on the pass. side, coil is on the block on the driver's side, above the dizzy. Dipstick goes into the oil pan, not the block, it has an Autolite carb. I will look for more identifiers if someone tells me what I am looking for.

It runs terribly .. at idle, it rumbles like it's constantly stalling, but doesn't actually stall ..


Carb stuff:
If I pull any vac line, especially the one off the brake booster, the RPM will increase and the engine will smooth out, but still not be right. If I leave a vac line off, so the engine runs better, it wont shift. Yes, I know this should be obvious but I am including all my observations here ..

I can see only one obvious mixture screw, at the bottom of the carb. I closed it (counted the turns) and it made no difference. I opened it passed where it was, no difference. I set it back to where it was and left it alone ...

There is a port off the TOP of the carb that has an inch of hose on it, and a very rusty phillip's screw-driver bit wedged in the hose :/ I hear no difference in idle if I pull it off or leave it there ..

Between the Carb and the intake manifold is what I assume is the PCV valve. It looks like a vacuum-actuated gate-valve. There is a nipple on the actuator, but a rubber cap over the nipple.. I do not see any other hoses to it. I reached in the back of the actuator with my fingers and do not feel the diaphragm moving, regardless of what I do with the throttle, and moving the diaphragm a little manually did not change anything. The spring is very strong in it.

There is a ****-yellow container below the battery with hoses running to it from the carb. There is also a half-inch inlet to this container with no hose at all. I cannot feel (with my thumb, haven't gotten a vac gauge yet) any vac or pressure in that container. The line that goes to the carb from that container has what LOOKS like a plastic fuel filter in it.


Plugs and wires stuff:
Dad showed me the trick years ago of pulling plug wires to listen to RPM changes to find out whether any given plug was actually firing or not. I pulled wires off at the dizzy, since I couldn't grip them well at the plug with the pliers I had. I pulled 1, 3, and 4, and could not hear any change in rumble or RPM..........

I spotted bubbles, yes bubbles, around plug 3 where it meets the block and pulled that plug. It was 100% black, and wet. I used a nail file to clean the gap a little and used a little starter fluid (ran out of carb cleaner) to rinse the plug and, gapped it at .044 put it back. the threads on the plug look fine, but it still doesn't seem to perfectly seat in the block, and still bubbles, just a little. I bought a set of plugs but have not put them in yet ... I ran out of money and cannot get plug wires or dizzy parts right now.. Oh, and the coil is healthy, my whole arm still hurts from touching the plier handle >.<


Other WTFs:
The truck has power steering, which works, but also a second pump which I can only assume WAS air conditioning and is not connected to anything, anymore, and no belt on it.

There is a tin heat shield on the exhaust manifold with a pipe extending forward and up (towards the battery tray) about 6 inches long and 3 in diam. What the hell is it ... I cannot see anything in this pipe other than the side of the exhaust flange ...

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If you've read this far, THANK YOU for taking the time!! I really do appreciate it and my wife and her mom will too!!!!

If you can help in ANY way, we'd all be eternally grateful!!!!!


"DieCastoms." Michael. Augusta Georgia.

 

Sounds like you have a handle on it. Why not give it a tuneup? Put the battery on a charger for a couple days won't hurt anything, almost free. New plugs are a good idea. You can pull the distributor cap and (mark the wires!) and clean it out with solvent, polish the plug sockets, scrape off the terminal corrosion, and if it's clean and dry will work just fine. Clean up the cable and starter connections, block and frame grounds. If you can check the float level while idling, that's almost free, and can cause the symptoms you describe. Try and smooth out the idle by setting RPM and mixture back and forth. Hope this helps.

 

Some pictures would help us help you. Have you changed the oil? If not, do and see how it looks/smells.

>>I can not find a number plate on the engine.. I've looked. Exhaust and intake are on the pass. side, coil is on the block on the driver's side, above the dizzy. Dipstick goes into the oil pan, not the block, it has an Autolite carb. I will look for more identifiers if someone tells me what I am looking for.<<

The casting number on the block is behind the starter. No worry, if it's an '81 with an inline it's a 300.

>>If I pull any vac line, especially the one off the brake booster, the RPM will increase and the engine will smooth out, but still not be right. If I leave a vac line off, so the engine runs better, it wont shift. Yes, I know this should be obvious but I am including all my observations here ..

I can see only one obvious mixture screw, at the bottom of the carb. I closed it (counted the turns) and it made no difference. I opened it passed where it was, no difference. I set it back to where it was and left it alone<<

A brake booster size vacuum leak should make it run much, much worse. Is the choke opening? There should be a metal line from the exhaust manifold to the choke housing in addition to any electric wires.

Vacuum leaks make an engine run like crap. It sounds like the carb may be puking gas.

I recommend taking the carb or the tag on it to a parts house and getting a rebuild kit along with a bucket of parts dip cleaner. The factory Carter YF 1v is very easy to rebuild.


>>There is a port off the TOP of the carb that has an inch of hose on it, and a very rusty phillip's screw-driver bit wedged in the hose :/ I hear no difference in idle if I pull it off or leave it there<<

Probably was the line to the purge canister (**** yellow thing referenced below)


>>Between the Carb and the intake manifold is what I assume is the PCV valve. It looks like a vacuum-actuated gate-valve. There is a nipple on the actuator, but a rubber cap over the nipple.. I do not see any other hoses to it. I reached in the back of the actuator with my fingers and do not feel the diaphragm moving, regardless of what I do with the throttle, and moving the diaphragm a little manually did not change anything. The spring is very strong in it.<<

That's the EGR valve, it should open during cruise to let exhaust gas mix with the fuel air. Since you're on a tight budget it's not a high priority.


>>There is a ****-yellow container below the battery with hoses running to it from the carb. There is also a half-inch inlet to this container with no hose at all. I cannot feel (with my thumb, haven't gotten a vac gauge yet) any vac or pressure in that container. The line that goes to the carb from that container has what LOOKS like a plastic fuel filter in it.<<

Charcoal canister to capture fuel vapor, low priority.


>>Plugs and wires stuff:
Dad showed me the trick years ago of pulling plug wires to listen to RPM changes to find out whether any given plug was actually firing or not. I pulled wires off at the dizzy, since I couldn't grip them well at the plug with the pliers I had. I pulled 1, 3, and 4, and could not hear any change in rumble or RPM..........

I spotted bubbles, yes bubbles, around plug 3 where it meets the block and pulled that plug. It was 100% black, and wet. I used a nail file to clean the gap a little and used a little starter fluid (ran out of carb cleaner) to rinse the plug and, gapped it at .044 put it back. the threads on the plug look fine, but it still doesn't seem to perfectly seat in the block, and still bubbles, just a little. I bought a set of plugs but have not put them in yet ... I ran out of money and cannot get plug wires or dizzy parts right now.. Oh, and the coil is healthy, my whole arm still hurts from touching the plier handle >.<<<

Start with the new set of plugs and go from there.


>>The truck has power steering, which works, but also a second pump which I can only assume WAS air conditioning and is not connected to anything, anymore, and no belt on it.<<

Top of the engine, passenger side? AIR injection pump.


>>There is a tin heat shield on the exhaust manifold with a pipe extending forward and up (towards the battery tray) about 6 inches long and 3 in diam. What the hell is it ... I cannot see anything in this pipe other than the side of the exhaust flange ...<<

There used to be a hose that ran to the bottom of the air cleaner assembly to provide heated air on cold starts. Not a requirement, low priority until you get it running right at temp.

 

Thank you for some awesome answers that I didn't have to wait weeks for!!!!

I have a funeral to go to, tomorrow, my wife's grandfather passed away rather abruptly last week. I will change the plugs out Friday, and take some pictures.

By the way, it is a rebuilt engine that was installed maybe 10 years ago .. being a 300 L6 is it likely the same engine that would have been in it in the first place, or a conversion?

The carb says autolite on it, so I am sure it's not the original YF 1v, but I will look up a rebuild kit this weekend.

Again, THANK YOU.

Diecastoms.

 

"...being a 300 L6 is it likely the same engine that would have been in it in the first place, or a conversion?"

It can go several different ways none of them being more likely than another.

 

Ok, the L6 showed me no love, at all, today ...

I found a guy on YouTube who owns the website Welcome to Mike's Carburetor Parts - Your Number 1 Carburetor Parts Store His website sells rebuild kits, etc., but also he has a 4-part youtube series on how to rebuild the yfa carb. It is not in-depth, as his kits come with more detailed instructions, but it showed me what things I could look for ...

I pulled the carb and broke it down and cleaned it as well as I could with canned carb/choke cleaner, made sure everything worked well and moved freely, and made sure all the passageways were clear and not plugged and put it back together.

I did not have a rebuild kit for it, because i can't get to the parts store. I hoped that pulling the carb apart and cleaning it would help, and I could then drive the truck TO the part store, and GET the kit, and I'd redo it all over again, with the new parts...

Mixture screw is not dented/scored, float valve was free and clean, spring is still in it where it belongs, accelerator pump was pumping nicely (I cycled some carb cleaner through it by hand, I did NOT take apart the acc. pump), the check ball and weight are still there. I did make sure that the metering needle was not bent, and set it per the above mentioned video, back it out, make the metering needle bottom-out, turn the set screw in until the screw touches, and then add 1 turn...

Throttle was tight in the throttle body, I did not take any of that apart, mostly because when I was working on it, I forgot it comes off.

I messed with the choke actuator, it is an electric choke.. the video showed how he adjusted it (rotate the choke body until the choke butterfly closes) and made sure it was moving freely ...

I changed all the plugs, gapped at .044, and made sure that the plug wires are on all the way. Only did one plug at a time, so I couldn't accidentally swap wires.. I popped the cover off the distrib. and did not expect it to be open at the bottom? I didn't see any white spark-traces or cracks or anything in the top, and no corrosion on anything, so I put it back on and left it alone ..

so here's where I am at ... everything is back together, the truck will start and runs like **** ...

Plugs 3 and 4 are leaking gas around them ... no matter how tight (no I didn't go insane) I can get those two plugs, they are still leaking.. I'm guessing those two cylinders aren't running . . . If I rev the engine, repeatedly, it revs smooth but will NOT idle, at all .. and the longer it runs, the rougher it gets .. maybe #3 and #4 are flooding too much .....

I am not sure what I will do next ... I'd really like to have ANYONE who knows what they're doing over my shoulder . . .

 

Check every vacuum line that is connected to the carb or intake for leaks. Feel around the vacuum tree to make sure no nipples are uncapped. With the engine running try spraying some carb cleaner around the intake runners on cylinders 3 & 4 to see it the manifold bolts have worked loose or the gasket blew out causing a leak there.

The leaking around the plugs is not good, at the very least it's bleeding compression. Try cranking the engine with the 3 & 4 plugs removed and see if anything is blowing out.

You can use a crayon on the exhaust manifold once the engine is heated up to see if any cylinders aren't firing.

 

Baron, intake is on the other side of the engine .. how could it be an intake gasket?

 

If the gasket is blown or the manifold is loose it may create enough of a vacuum leak to keep the cylinders from firing.

Did you have a chance to drain and check the oil? If there's any water/coolant the head gasket could be suspect.

 

but how would that make the spark plugs leak?? I'm not seeing the connection here . . .

 

Wouldn't cause the leak but might be why those cylinders aren't firing, it they aren't.

Leaking around spark plugs may mean a warped or cracked head. Or maybe just a marred mating surface. If it's just not sealing you may be able to stop gap with some thread sealer.

 

That Mike vid of him rebuilding carb was pretty cool. I've never done carb work. so cool to see