Engine stalls under a load

[dimeguy]

Hey guys,

 

So I was pretty excited to get my car back from my uncle's. I've been out of town but he was able to get it running consistently. When he pulled it off the trailer he drove it up and down the street for about 5 min or so and it didn't seem to have any issues. After he parked it and took off I washed it and got ready for a quick spin. It cranked instantly and held a smooth idle no problem. When I started up the driveway the it started to stall out. At about 1/3, throttle trying to get up hill, the car sputters and dies. If I rev it in gear with my foot on the brake it does the same thing. When at a stand still, I can rev it in neutral and there are no issues. I pulled the air filter and covered the carb and it started to die instantly so I assumed it wasn't a vacuum issue. Adjusted the timing with no luck, adjusted the idle and mixture screws on the carb but still encountered the same problem. I noticed the hard line to the vacuum advance was disconnected and reattached it with no change. I've never had any issues like this with the car before. Is it an ignition problem or maybe my carb going bad?

I searched around the forum a bit and found similar problems but nothing quite like my situation. Thanks for any help.

 

-1970- 510 2 door auto

-stock hitachi car and stock distributor

-timing may have been adjusted without my knowledge

-I have a Haynes, "how to rebuild your...", and the DQ's to reference

[datzenmike]

Wet wires. Water under the distributor cap. Take it off and dry.

[bilzbobaggins]

is there fuel in the sight window on the front of the carb? What does your fuel filter look like?

[dimeguy]

I removed the cap to look inside the distributor and never saw any moisture. I'm pretty inept with electrical systems, but I did notice the wires in the distributor below the rotor were frayed and looked kinda rough. Also I replaced the plugs and wires a little while back.

 

The fuel level looks good, in between 1/2 and 3/4 full. Filter looks old but in decent shape. I have had the car in storage over the past 2 years and the last time I filled the tank was about 1.5 yrs ago. Could it be old crappy gas?

[datzenmike]

Gas is fine. If it sat that long the gas in the carb probably gelled or dried up. This will leave a deposit inside the float chamber that may be blocking the primary jet.

[dimeguy]

It has been in and out of storage. I cranked it and let it idle each time I pulled it out. I think it sat for 3-4 months at the longest without being cranked.

[datzenmike]

Well won't be that then. You only idled it then? It may have had a problem under load all along for 2 years.

[dimeguy]

Possibly, but the car was driven down the street when I got it home and it didn't have the problem. It had a little smoke coming out of the tail pipe but that's it.

[DanielC]

When I put my boat to bed for the winter, a very sad day, I make it a point to fill the gas tank almost full, just below the point gas will come out if it gets warm.

The less air in the gas tank, the less condensation in the tank. And Oregon is not near as humid as Atlanta.

 

It would not surprise me if you had some water in the gas tank, and driving it around, a shot of water got sucked into the carburetor.

[dimeguy]

I wouldn't think it would be water in the carb only for the fact that the engine turns over instantly every time and holds an idle no problem. I can rev high in neutral with no problems. It's only when it is in gear. I have never dealt with water in the carb though, does that still sound likely?

[usaf_daddy]

Check your fuel pressure sitting all the time will do no good to a fuel pump it may idle with a bad fuel pump but no go under load. Also smell your oil for gas another sign that it has gone bad

[datzenmike]

I wouldn't think it would be water in the carb only for the fact that the engine turns over instantly every time and holds an idle no problem. I can rev high in neutral with no problems. It's only when it is in gear. I have never dealt with water in the carb though, does that still sound likely?

 

Well the idle circuit is separate from the primary barrel. The primary could be completely blocked but it will still idle. Water is heavier than fuel and will be low in the float chamber right where the primary and secondary jets are. I've had this happen and (if it's water) just drive it around and it clears out. You can also pour a half liter of isopropyl alcohol in the tank. It will mix water and gas molecules together and thin it out enough to pass through the jets. It's also known as gas line anti freeze.

[bilzbobaggins]

Auto transmission issue?

[ggzilla]

This usuallly happens with automatics (running fine but ENGINE DIES under load). Does the engine quit running? Or just sputter/cough/hiccup/spit? Any backfiring?

 

I would do this. Remove the cap and don't look in the distributor. Look in the CAP. Any visible lines in there? It will misfire under load. Any water? Even a spec can cause it to misfire under load.

[dimeguy]

That all sounds like good stuff. The engine will sputter/stutter(when in gear at or beyond about 1/3 throttle) and if I'm quick to let off the gas it comes right back, but if I remain on the gas it will die. I also noticed that while parked if I hold the throttle cable/link so that it's wide open it runs really rough and takes about 5-10 sec to recover and get back to a normal idle. Have not noticed any backfiring though.

 

I'll double check the distributor cap and try adding .5L of Isopropyl Alcohol in the tank and see how it does.

 

Thanks for the suggestions, I'll keep you guys posted.

[datzenmike]

If the tank is low just a cup will do.

 

Did I say to check the plug wire order? 1342 clockwise direction on cap. Usually #2 and #3 are switched.

[dimeguy]

Unfortunately I've got the car in the driveway and it has been raining so I'm going to wait until dry sunlight tomorrow. I've had the car for close to 2 years and haven't posted anything about the car or pics yet. I was hoping to have it going as my daily driver before I made a grandiose intro. But, this forum has been a life saver and I figure it is time to post a little about my short journey and pics of the car...

 

I grew up in the SE where Datsuns all but cease to exist. I saw a 510 in high school parked at a random house and stopped to look at it. It was in terrible shape and I knocked on the door to ask if I could buy it. A nice older lady told me her son recently bought and wouldn't sell it to the world. I was never able to really get my hands on one in high school, nor were my parents willing to put up with the hassle of it while I lived with them. I eventually but any dreams I had in the back of my mind and went to college. After a few years of college, I joined the military and found myself in "no-where Alabama". I was perusing craigslist with no purpose when I came across a 1970 510 for sale. The ad said the car still ran and it was just 10 min down the road. It was listed for 2k. I had just recently saved up a good chunk of cash and I was instantly enthralled. I called the guy to look at the car that night. A week later he drove the car to my house and I gladly paid him every penny he was asking. Below are pics of the car. The garage pics are how I first bought it. Since I purchased the car I have been busy with the military but replaced the front brakes, thanks to Ratsun members and DQ, and picked up a set of super cool(before you jump on me that's sarcasm) wheels to cover aforementioned brakes. Once I can get the issue at hand dealt with I want to upgrade from the points, premature thanks for the right up on that one. I got really lucky with the car as you'll notice it is in great shape. But, probably the coolest thing about this car(aside from rarity and location) is that it came with the original window tag. So, if you're not asleep yet...

[dimeguy]

 

 

 

 

[datzenmike]

A fine car for under 2K!!!!

[alabama_lowlife]

Is No-where, Alabama in Ft Rucker?

[dimeguy]

Haha no way. You hit the nail on the head. Good old mother Rucker.