Ford F834 Posted December 17, 2017 Author Share Posted December 17, 2017 The YF, if that is what you have . . has a design element I don't like. The accelerator pump is such that if the diaphragm rips( and they all do eventually) not only does the acceleration circuit not work, but now the carb will be overly rich. This is because fuel will actually drip into the venturi area from a rip in the diaphragm. If you ever have a rich problem, it's something to check for sure. Thanks. I do have a YF and that is a good tip. The carb is a fresh Napa rebuild that came with my parts truck but that means nothing to me. I've been round and round with rebuilds and usually the core got turned because it was worn out too badly for a rebuild kit to do any good. I owned a '72 Comet for about two years and went through 21 (yes, twenty-one) parts house warranty carburetors. Some sprayed gas all over the engine right out of the box in the parts house parking lot. Had to go back in for my old one just to not be stranded. So my faith in rebuilds is not there. I'm going to try the one from my 1968, and if I'm not happy then I will try to get one from a company in Canada that David suggested. They actually bush the shafts and rebuild them to last. If that does not work then it's aftermarket intake time and bye bye one barrel (but I hope not). Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 17, 2017 Share Posted December 17, 2017 The YF, if that is what you have . . has a design element I don't like. The accelerator pump is such that if the diaphragm rips( and they all do eventually) not only does the acceleration circuit not work, but now the carb will be overly rich. This is because fuel will actually drip into the venturi area from a rip in the diaphragm. If you ever have a rich problem, it's something to check for sure. Thanks. I do have a YF and that is a good tip. The carb is a fresh Napa rebuild that came with my parts truck but that means nothing to me. I've been round and round with rebuilds and usually the core got turned because it was worn out too badly for a rebuild kit to do any good. I owned a '72 Comet for about two years and went through 21 (yes, twenty-one) parts house warranty carburetors. Some sprayed gas all over the engine right out of the box in the parts house parking lot. Had to go back in for my old one just to not be stranded. So my faith in rebuilds is not there. I'm going to try the one from my 1968, and if I'm not happy then I will try to get one from a company in Canada that David suggested. They actually bush the shafts and rebuild them to last. If that does not work then it's aftermarket intake time and bye bye one barrel (but I hope not). I vote for this. (Dad used to say "Misery loves company". ) Link to comment Share on other sites More sharing options...
Ford F834 Posted December 17, 2017 Author Share Posted December 17, 2017 I vote for this. (Dad used to say "Misery loves company". ) You have a point. I tend to want to stay as simple and mechanical as possible, but those parts are readily available and probably cheaper than a fancy aftermarket intake + carb. I just hope I can get a good working YF and run it... at least for now. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 17, 2017 Share Posted December 17, 2017 You have a point. I tend to want to stay as simple and mechanical as possible, but those parts are readily available and probably cheaper than a fancy aftermarket intake + carb. I just hope I can get a good working YF and run it... at least for now. You are going where, which is at what altitude? (282') And you work where, which is at what altitude? (7000') And you are going with me to the North Rim at 8000'. You expect your carb to automagically adjust for that? It is one thing for folks like David who lives at 548' and sometimes drives to Skiatook where it is a whole 646' above sea level. But, where you drive has got to change the air fuel ratio significantly. So, my suggestion would be to start acquiring the parts as you frequent the salvages. Then, when I get proficient at this...... Seriously though, we got lucky that Ford EFI'd the 302 during the Bullnose era. And then they continued to use the same high-pressure pump on all of the vehicles, from the 300 to the 460. So, we can use the 302's fuel system and sending units, and both the EFI and our gauges will work. Link to comment Share on other sites More sharing options...
PetesPonies Posted December 17, 2017 Share Posted December 17, 2017 You are going where, which is at what altitude? (282') And you work where, which is at what altitude? (7000') And you are going with me to the North Rim at 8000'. You expect your carb to automagically adjust for that? It is one thing for folks like David who lives at 548' and sometimes drives to Skiatook where it is a whole 646' above sea level. But, where you drive has got to change the air fuel ratio significantly. So, my suggestion would be to start acquiring the parts as you frequent the salvages. Then, when I get proficient at this...... Seriously though, we got lucky that Ford EFI'd the 302 during the Bullnose era. And then they continued to use the same high-pressure pump on all of the vehicles, from the 300 to the 460. So, we can use the 302's fuel system and sending units, and both the EFI and our gauges will work. I just had the YF on my '71, try and leave me stranded the other day. It was something that had gotten into the seat and the needle wouldn't close enough. Not sure what it was, couldn't identify it. Not rust, was silver, but not metal. I added another filter and dared it to do it again :) Link to comment Share on other sites More sharing options...
Ford F834 Posted December 17, 2017 Author Share Posted December 17, 2017 You are going where, which is at what altitude? (282') And you work where, which is at what altitude? (7000') And you are going with me to the North Rim at 8000'. You expect your carb to automagically adjust for that? It is one thing for folks like David who lives at 548' and sometimes drives to Skiatook where it is a whole 646' above sea level. But, where you drive has got to change the air fuel ratio significantly. So, my suggestion would be to start acquiring the parts as you frequent the salvages. Then, when I get proficient at this...... Seriously though, we got lucky that Ford EFI'd the 302 during the Bullnose era. And then they continued to use the same high-pressure pump on all of the vehicles, from the 300 to the 460. So, we can use the 302's fuel system and sending units, and both the EFI and our gauges will work. I've used my trucks from Phoenix (a few hundred feet elevation) up to snow bowl on the San Francisco peaks (9,000'). I'm sure the singular carb setting isn't ideal, but I didn't notice any huge problems with performance or mpg. If I'm hauling heavy at altitude I do notice some pinging with the 240, but haven't noticed it with the 300's that I've had (different CR?). I know EFI keeps things more optimal, I'm just not sure if I'd find the juice to be worth the squeeze. Maybe if I drove an EFI I'd never want to go back, but my main beef with carbs has been the perpetual slight stutter and stumble no matter what you do to tune them. I noticed the effects of altitude more with the diesel because I could ~see it 🙄 Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 17, 2017 Share Posted December 17, 2017 I've used my trucks from Phoenix (a few hundred feet elevation) up to snow bowl on the San Francisco peaks (9,000'). I'm sure the singular carb setting isn't ideal, but I didn't notice any huge problems with performance or mpg. If I'm hauling heavy at altitude I do notice some pinging with the 240, but haven't noticed it with the 300's that I've had (different CR?). I know EFI keeps things more optimal, I'm just not sure if I'd find the juice to be worth the squeeze. Maybe if I drove an EFI I'd never want to go back, but my main beef with carbs has been the perpetual slight stutter and stumble no matter what you do to tune them. I noticed the effects of altitude more with the diesel because I could ~see it 🙄 I've driven from here to the South Rim (7000' for the others), towing, with a carb and didn't have a problem, although the engine was seriously down on power. But once when headed up Pike's Peak with my '72 F250 I lost enough power that we had to drop the motorcycle trailer we were towing in order to make the climb. The rule of thumb is to go 2% leaner per 1500' of elevation change. With us at 750' and the North Rim at 8000' or more a carb would be about 10% too rich. If the tune was lean to start with you might not have a problem, but if spot-on then the extra 10% probably would be very noticeable - both in power and in the exhaust. Link to comment Share on other sites More sharing options...
Nothing Special Posted December 17, 2017 Share Posted December 17, 2017 I've driven from here to the South Rim (7000' for the others), towing, with a carb and didn't have a problem, although the engine was seriously down on power. But once when headed up Pike's Peak with my '72 F250 I lost enough power that we had to drop the motorcycle trailer we were towing in order to make the climb. The rule of thumb is to go 2% leaner per 1500' of elevation change. With us at 750' and the North Rim at 8000' or more a carb would be about 10% too rich. If the tune was lean to start with you might not have a problem, but if spot-on then the extra 10% probably would be very noticeable - both in power and in the exhaust. I took my '85 F-250HD up to about 14,000 feet from my 750' home elevation. As I recall there was an idle mix adjustment on the stock 2 bbl which I tweaked to get it to start, but I really didn't have any trouble other than that. Not saying it was running right, I'm sure it was extremely rich (no cats on that truck so I didn't need to worry about that), and we just had the truck loaded with 2 people and a weeks worth of camping gear, so not much load. But you can get by with a lot for a short time if you need to. Link to comment Share on other sites More sharing options...
Ford F834 Posted December 18, 2017 Author Share Posted December 18, 2017 I've used my trucks from Phoenix (a few hundred feet elevation) up to snow bowl on the San Francisco peaks (9,000'). I'm sure the singular carb setting isn't ideal, but I didn't notice any huge problems with performance or mpg. If I'm hauling heavy at altitude I do notice some pinging with the 240, but haven't noticed it with the 300's that I've had (different CR?). I know EFI keeps things more optimal, I'm just not sure if I'd find the juice to be worth the squeeze. Maybe if I drove an EFI I'd never want to go back, but my main beef with carbs has been the perpetual slight stutter and stumble no matter what you do to tune them. I noticed the effects of altitude more with the diesel because I could ~see it 🙄 Woah! What a difference a carb can make... I put on the carb from my 1968 truck and that was definitely the problem, or at least a problem. It idled way lower and the timing was drastically different (over advanced) compared with the old one. I put the timing light on it and set it to 6* which is what the emissions sticker specified. The truck didn't like 6* very much. I bumped it up to 10* which was the other possible spec listed in the Chilton manual and it liked that much better. I don't know why some got 6* and some got 10* but I'm going with what works. It still has a brief hesitation when I goose the throttle, but I don't have a vacuum gauge to check the carb ports. I tried a couple different ones with no change. I might try manifold vacuum if I can get the right adapter, but I don't usually drive by stabbing the throttle anyway. After the carb change and timing, the truck runs smoother, and has way better response especially at higher rpm's.Before it sounded really awful at around 2,500... now it roars over 3,000 with ease and sounds healthy. It feels stronger while driving too, with better torque and pull throughout the rpm range. After all the funny business I checked the cap and rotor and they were a bit toasted. I swapped in the cap, rotor, and wires from the '68. I checked the plugs also, and they seemed good. All were gapped pretty close to .042 and looked like this: I traced and fixed a broken wire to the driver side low beam headlight, and pulled the blower motor to look for mouse activity. They have obviously been in there, although there was not much nest evidence. Tomorrow I will open the whole thing up and take care of business. Because of the issues with the camper it's looking like we will head out Wednesday. I'm glad to have gotten the tune up stuff done though, and I'm hoping for better mpg results. The speedometer is reading a bit lower than before the bigger tires. It's pretty close up through ~30ish, but 55 on the dial=60. On the odometer 1 mile = 1.165 actual miles. If I'm 16.5% low, I wonder if I could make a metric speedometer read as miles by going ~UP in driven gear tooth count? It might be one way to get it numerically correct even if the units are wrong Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 18, 2017 Share Posted December 18, 2017 Woah! What a difference a carb can make... I put on the carb from my 1968 truck and that was definitely the problem, or at least a problem. It idled way lower and the timing was drastically different (over advanced) compared with the old one. I put the timing light on it and set it to 6* which is what the emissions sticker specified. The truck didn't like 6* very much. I bumped it up to 10* which was the other possible spec listed in the Chilton manual and it liked that much better. I don't know why some got 6* and some got 10* but I'm going with what works. It still has a brief hesitation when I goose the throttle, but I don't have a vacuum gauge to check the carb ports. I tried a couple different ones with no change. I might try manifold vacuum if I can get the right adapter, but I don't usually drive by stabbing the throttle anyway. After the carb change and timing, the truck runs smoother, and has way better response especially at higher rpm's.Before it sounded really awful at around 2,500... now it roars over 3,000 with ease and sounds healthy. It feels stronger while driving too, with better torque and pull throughout the rpm range. After all the funny business I checked the cap and rotor and they were a bit toasted. I swapped in the cap, rotor, and wires from the '68. I checked the plugs also, and they seemed good. All were gapped pretty close to .042 and looked like this: I traced and fixed a broken wire to the driver side low beam headlight, and pulled the blower motor to look for mouse activity. They have obviously been in there, although there was not much nest evidence. Tomorrow I will open the whole thing up and take care of business. Because of the issues with the camper it's looking like we will head out Wednesday. I'm glad to have gotten the tune up stuff done though, and I'm hoping for better mpg results. The speedometer is reading a bit lower than before the bigger tires. It's pretty close up through ~30ish, but 55 on the dial=60. On the odometer 1 mile = 1.165 actual miles. If I'm 16.5% low, I wonder if I could make a metric speedometer read as miles by going ~UP in driven gear tooth count? It might be one way to get it numerically correct even if the units are wrong I'll bet the carb makes a big difference in MPG if it made that much difference in power and driveability. On the timing, if it can handle 12 or even 14 degrees without kicking back on starting or pinging I'd give it a try. As for the speedo, that is exactly the way Big Blue's is - I have to add 5 MPH to whatever it shows. I need to see what I can do about that, but it didn't work very well at all when I got it, and lubing the cable made it nice and steady - but wrong. The blower's squirrel cage doesn't look very good, and that may cause a balance problem. Anyway, if there was no nest are you going to have to clean the ducts out with a cleaner to get the smell out? Link to comment Share on other sites More sharing options...
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