Fuel Pump question

I have recently acquired a '61 CJ5 that has been sitting on my wife's grandfather's farm for the last number of years and am now in the process of trying to get it running again and maybe learn something about auto repair along the way. It has various obvious issues with it that need to be addressed including the brakes, steering, and replacing the plastic marine gas tank strapped in behind driver's seat before it can be safe for the road again....not to mention a lot of cosmetic work. I'm not quite sure how long it's been sitting, but my understanding is the before it was parked some years ago, the engine ran pretty well. I have a receipt for the engine rebuild back in '99 so it's certainly sometime less than that.

In any case, I've changed the fluids, put in a new battery and tried to get it started. The engine turned over but wouldn't start. I looked at the fuel pump/filter (I've got one with the glass casing on the top), but it looked dry....not surprising since it's been sitting for so long. I was able to squirt some gas directly into the carb and the engine would run for a couple of seconds until the fuel was used up then it would cut out so at least I appear to be getting some spark. After pumping the gas pedal for a while starting it...thinking that it might just need more time to work fuel through the line and into the pump, but there doesn't appear to be any gas getting into it. I checked the fuel line (visually) and all the connections appear to be intact and I don't see any fuel dripping out as might be the case if I had a crack in one of the rubber tubes. I pulled the glass top off the fuel pump and verified that the contents inside it were bone dry.

Are there any things that I would need to check before determining that the fuel pump is bad and needs to be replaced or is that the next step in the troubleshooting process?

Thanks

Dave

 

Take the fuel line off the tank and the pump and see if you can blow through it.A air compressor would be handy,I've seen fuel line come apart on the inside before.

 

The outlet tube of the tank could be plugged.

 

I would try setting up an alternate tank and a line straight from it to the intake side of the fuel pump to see if it will pick up gas. The tank itself may have debris at the pickup.
It could be that the diaphragm has dry rotted and broke. If this happens it can start dumping gas into your oll and damage the bearings. Check your oil often even if it starts pumping.
Also, If my brain is working right, your fuel pump is a combination fuel/vacuum pump. The top part with the glass dome is the vacuum pump.

Scott

 

" The top part with the glass dome is the vacuum pump. "

I think not. The vacuum side is the bottom of a dual pump, at least on my jeeps.

A failure to suck fuel might be as simple as a leaky (dried out) gasket under the glass dome.

 

I guess I stand corrected. I knew it was a dual system, I've got one out in the shop, I'll have to look at it and educate myself on how it is structured. Either way I wanted freewillys to be aware of the dual nature of that pump.

Scott

 

Thanks for the info guys. I'll see about replacing the rubber fuel lines this week, including the portion that dips down into the fuel within the tank. I pulled one of them off and the rubber seemed kind of stiff and brittle although it didn't appear to be cracked. As for the dual nature of the pump (fuel and vacuum), all I can see are 2 lines coming out of it. One for the inbound fuel from the tank and the other outbound going to the carb. For a dual system, would I expect to see more lines going in/out with the vacuum being used for the wipers? My wipers appear to have been altered somewhere along the way as the motors are mounted on the bottom of the windshield vs on top for other '61 CJ's I've seen. I'm pretty sure they're electric even though they're not working now. Also, since this is a mechanical fuel pump, does the motor need to be running for the fuel pump to start or will the turning of the motor while cranking it start the flow of fuel through the pump? I'm just trying to get a better understanding on how the system works and the manuals go into more detail about replacing the pump and not much about how this specific type actually works.

@Glenn - at some point before getting my CJ on the road I plan on replacing the existing plastic marine fuel tank mounted behind the seat (held down with a seat belt believe it or not), but that brings me into the bigger question of where to relocate it. I know the simple answer would be to buy a new one and put it under the front seat as designed, however, for some reason the prospect of sitting inches above my fuel tank with only the seat between us leaves me unsettled. Maybe that's just something I have to get over because at this point, I don't have the tools nor the skill set to do the metal work at this point that would be required to relocate where the post 1970 CJ's were located.

 

Your dual pump may have been replaced with a fuel only unit, if the wipers were converted to electric.

Cranking the motor will operate the pump, but it will take a minute or two of cranking to fill. You could try applying vacuum to the output line to speed things along.

 

1st remove the hose from the inlet side of the pump. 2 if you have a vacuum Gauge place it there. Crank it you should see suction. No Vacuum gauge use a finger. The hose you removed fuel should drip fuel out if not remove the cap and blow air in mouth will work if no compressor is handy. If it has suction and a fuel supply the pump should work.

 

I have always used a tire-pump to do that. Pull the cap, and have some one listening to the tank opening. They should be able to hear bubbles burbling or air rushing in.

 

I finally got the CJ to start up this morning. It won't hold an idle and will cut out if I stop giving it gas, but at least I feel like I've made some progress. It runs pretty rough as you might expect after sitting for many years, but the exhaust was pretty clean. It doesn't appear to leak any oil with the exception of the small amount that's seeping from the oil pressure gauge, but from the look of the crusty oil surrounding the edge of the gauge face, that's a previous existing condition.

I ended up replacing the fuel pump and all the rubber fuel line segments on the tank side of the fuel pump. I didn't seem to have any blockage when I blew air through the line (using a small pump used for pumping up footballs), but there were 3 separate pieces of line clamped together from the tank to the beginning of the steel portion underneath the driver seat so I'm better off with a single piece now. As I mentioned before, I have a marine gas tank sitting behind the driver seat, and even after the line replacement and new fuel pump, I still wasn't getting gas through the line. I ended up temporarily putting a primer right at the tank which seemed to get the flow going because it started after that. I had a leak on the line from the fuel pump to the carb, but luckily that turned out to be user error as I didn't tighten down the end that screwed into the fuel pump enough. It wasn't until I was talking to the guy at the auto parts store and playing with the metal connector that I realized my mistake. The nut on the end of the connector appeared to be tight against the fuel pump, but I still had some play with the hose...which meant I didn't have a good seal. I'm guessing it's designed that way so the rest of the line doesn't twist with every turn of the nut as I tightened it down. When the rest of the line started to turn as I finished tightening, the play was gone and so was the leak. Oh well lesson learned. Better to figure it out in my garage vs on the road.

 

Congratulations! Once a vehicle will at least run, it is so much esier to diagnose one item at a time.

Sounds like a carb cleaning is your future, at least the idle jet. Or possibly you have a vacuum leak.