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I took the '61 Olds 98 out for a drive yesterday and on the way home, the car started sputtering, as if starved for fuel. I feathered the gas pedal, which kept it running enough for me to turn off the main strip onto a side street. I popped the hood, no leaks, no smell of fuel. Fuel tank was about 1/2 full. I tried to start it again after letting it sit for about 5 minutes, and it would barely start but then die. Anytime I would apply any throttle, it would immediately die. I had to let it sit overnight and come back to investigate this morning. I tried to start it up first thing and it started right up; I drove it down the side street so I could turn it around and head out to the main strip to go home. As I was driving, same thing. It ended up stalling on the same street. I unhooked the fuel line to carb and gas was coming out of the line which to me, means fuel is getting to the carb at least. I'm thinking the issue lies at the carb and further. Any ideas folks? This has never happened before. Nothing has been changed or altered since the carb rebuild a couple months ago. Rochester 4GC, 394 motor.
Mike - Honestly, I don't know what the issue is. Is it rather blazing hot in Eden Prairie today, by chance? I don't know some specifics about the fuel system of a '61 98 e.g. type of fuel filter, location, etc. I'm assuming you have an OEM style mechanical fuel pump. There "might" be a chance you're experiencing a vapor lock. There would exist more of a chance of vapor lock if the fuel lines (system) were re-routed from their original locations. I don't want to head down a rabbit hole w/ this, but vapor locks were not uncommon back in the day right about up to the time period of your car. I mention this solely for one reason. As you described the scenario the 1st thing which came to my mind was a vapor lock. Again, it doesn't mean that is what is occurring, but if by chance the fuel lines were replaced and re-routed (in particular let's say by a previous owner/shop), the fuel can boil, which creates vapor, and the vapor needs to dump somewhere - you can lose supply pressure into carburetor and/or the carburetor bowl can run empty starving the engine of fuel. You let it sit overnight, the vapor (lock) is gone, the engine fires back up and you're good to go. However, in your condition, it happened again directly after you fired it back up this morning. Almost sounds like the fuel bowl my be depleted of fuel. I can't recall the innards of the 4GC well enough to know if it had a vapor vent and I don't know if there was a fuel return line from the fuel filter on your car (which dumps fuel vapors). The type filter I'm talking about would have one fuel line into the filter but two lines leaving the filter. I don't know well enough to know. I'm w/ you though, sounds fuel related.
Mike - Honestly, I don't know what the issue is. Is it rather blazing hot in Eden Prairie today, by chance? I don't know some specifics about the fuel system of a '61 98 e.g. type of fuel filter, location, etc. I'm assuming you have an OEM style mechanical fuel pump. There "might" be a chance you're experiencing a vapor lock. There would exist more of a chance of vapor lock if the fuel lines (system) were re-routed from their original locations. I don't want to head down a rabbit hole w/ this, but vapor locks were not uncommon back in the day right about up to the time period of your car. I mention this solely for one reason. As you described the scenario the 1st thing which came to my mind was a vapor lock. Again, it doesn't mean that is what is occurring, but if by chance the fuel lines were replaced and re-routed (in particular let's say by a previous owner/shop), the fuel can boil, which creates vapor, and the vapor needs to dump somewhere - you can lose supply pressure into carburetor and/or the carburetor bowl can run empty starving the engine of fuel. You let it sit overnight, the vapor (lock) is gone, the engine fires back up and you're good to go. However, in your condition, it happened again directly after you fired it back up this morning. Almost sounds like the fuel bowl my be depleted of fuel. I can't recall the innards of the 4GC well enough to know if it had a vapor vent and I don't know if there was a fuel return line from the fuel filter on your car (which dumps fuel vapors). The type filter I'm talking about would have one fuel line into the filter but two lines leaving the filter. I don't know well enough to know. I'm w/ you though, sounds fuel related.
So, it hasn't been too warm here in Eden Prairie. Today is cloudy and stormy, supposed to be humid and 95. When I took her out yesterday evening, it was about 79 degrees, very comfy. The car was just about to operating temperature when it started acting up. I believe I followed the original lines pretty close. The original lines were of course rubber hose from pump to metal filter, then rubber to carb again. I switched that out long ago with all steel lines. This happened very suddenly. I do know that the fuel pump is leaking some oil after my rebuild, but it has been running just fine with that leak. Has the mechanical fuel pump finally gone? Could the issue be the fuel pump? I did see fuel coming out when I disconnected the steel line right at the carb inlet. I guess it'll just sit in the garage until I decide to go tinker.
That's right I forgot you recently rebuilt the fuel pump. I think I commented on the oil in that thread? Well, there should obviously be no oil coming out of a mechanical fuel pump. Me, I'd rather replace the entire fuel pump than rebuild it - just me.
That's right I forgot you recently rebuilt the fuel pump. I think I commented on the oil in that thread? Well, there should obviously be no oil coming out of a mechanical fuel pump. Me, I'd rather replace the entire fuel pump than rebuild it - just me.
That's where I'm at with it now. Waiting on approval for an offer I made on eBay for a rebuilt unit. Not very expensive. I agree, I think that's the way to go.
I have no knowledge of the various mechanical fuel pumps for your car, but I always try to do as much research in availability of various manufacturers for any parts. I've bought Carter mechanical fuel pumps in the past & found them to be decent high quality. Here are the ones RA lists...I always check model numbers and any important information as well in the "information" section(s) of various manufacturers. The more they provide, most often the better the quality.
Right on Norm. So that link to RA suggests electric fuel pumps, which I've tried before, but I like keeping this thing as original as possible, using the mechanical pump. I've found the correct fuel pump on eBay, just have to wait and see if I can get it for a better deal than the seller posted.
'New' original pump showed up today. Slapped her on, and the thing fired right up and kept running. The real test will be getting out for a drive, but unfortunately, I have some leaks at both tube nuts to inverted flare fitting from the pump to the fuel filter. I'll probably have to redo the line with the leaks, with new double flares and install new fittings.
Any suggestions for quality inverted flare, 3/8 hardline fittings?
Try loosening and tightening the flared connections several times. When you make the last application of tightening torque make it with a quick motion...rinse and repeat
I tried the tightening method, with no success. I think I will need to start fresh, which is ok by me. But I do have a question and need input. Instead of chasing for the correct reducing fittings, could I use rubber hose from fuel pump to the fuel filter? And then of course use hard line from the 'out' of the filter to the carb. Here are some pics. The rubber hose would be much shorter, obviously. I would rig something up to secure the filter to the block, or nearby area. Thoughts? Stick with hard line throughout? (Finding the least amount of reducing fittings for 3/8 hard line to 1/8 MNPT is a bear. Carb inlet is 1/8" and both inlet and outlet of fuel filter is 1/8")
Bending that hard line sure is a son-of-a, but I have done it before. The trick is finding the proper reducing fittings for my application here. Summit doesn't have them, but I found Advance Auto may have what I'm looking for. Here are 2 pics. The steel line would be double flared. This end would thread into the carb inlet fitting.
Inline Tube may be able to sell you a correct fuel line complete with appropriate flares and fittings. While you're waiting for that to show up, on a temporary basis you could go with gasoline-rated rubber hose just to make sure you've solved the fuel delivery issue. Also be aware that the ILT piece will probably require some tweaking with a hand-held tube bender for an exact fit.
Last edited by BangScreech4-4-2; Jul 20, 2024 at 06:11 PM.
Rubber products have improved enormously in the last 100 years with a multitude of various natural and synthetic rubber products. Viton Rubber fuel hose is probably the best you can buy.
Here's an update: I actually found the fittings I needed at a local parts store. They were discontinued according to their system. I have been looking for these for a while, so I grabbed several. This will allow for minimal fittings and will allow me to go back to hardline all the way. EXACTLY what I needed. Unreal. Hard to find these adapters apparently.
I use copper nickel brake line for my gas lines, bends and flares much better than steel, probably seals better on the flare also.
I've kind of gotten good at flaring the 3/8 steel line. Since it's tougher to work with, I place the flaring tool in the vise after I tightened it up. I clamp it pretty good and then throw a vise grips on it as well, to ensure it doesn't slide through when flaring. Works perfectly every time!
OK guys, with those fittings I found at the parts store, and newly bent 3/8 steel line, we're back up and running! I haven't taken the Olds out for a drive, but she fired right up and purred. So glad that the issue was the fuel pump, I was getting worried it was a little more in-depth than that. I fear that I may not have reassembled the valves correctly during the rebuild. They were a different style than the old ones that came out of the pump I was rebuilding. Anyway, checking for leaks at all the connections, and will tackle the next project: replacing the rear bumper with one that's in MUCH better shape, without dents, from eBay.
Sounds like you have this issue resolved. Good. Did you give up on the GEN issue? Did you send the load pile tester back?
Yep, this fuel issue is in the bag!
As for the load pile tester, that got sent back. I ended up searching on eBay for an original VR for my Olds. Never used, old box, VR looked to be in great shape. 35 amp, exactly what my system calls for. I figured what the heck. I installed it and the GEN light came on. I thought "wait! I bet I have to polarize the generator since this is new." Sure enough, after polarizing, GEN light out, voltage good! I think I am sitting right where I want to be, electrically. Running engine giving me 13.4 at idle, with higher RPMs giving me around 14.8. Seems to me that things look good on the charging issue.
Yep, this fuel issue is in the bag!
As for the load pile tester, that got sent back. I ended up searching on eBay for an original VR for my Olds. Never used, old box, VR looked to be in great shape. 35 amp, exactly what my system calls for. I figured what the heck. I installed it and the GEN light came on. I thought "wait! I bet I have to polarize the generator since this is new." Sure enough, after polarizing, GEN light out, voltage good! I think I am sitting right where I want to be, electrically. Running engine giving me 13.4 at idle, with higher RPMs giving me around 14.8. Seems to me that things look good on the charging issue.
I'm happy with those numbers. Learned a lot going through all this for sure. On a different note, I was able to get the 4-way electric seat to work after God knows how long it was inoperable for. It most likely didn't work even when my grandpa owned the car, so, late 80's. I took apart the transmission cluster and cleaned out and lubed the plastic gears. I also had to find a coupler on eBay to connect the drive motor to the transmission for the seat cables. I can now drive the Olds comfortably and am able to move the bench seat whenever and however I want. Making progress here.