nbs2005

Hi Folks,

I have a 1985 12a rx7 that's been prepped for IT7. I bought the car a few months ago. It has always been very difficult to get running. There is usually lots of cranking and playing with the installed fuel pump switch. Once running, it seems to work out fine.

Well today I wasn't able to start it. I've fired it up the last 3 days in a row and let it run for 15-20 minutes in the hopes that it would behave itself for this Sundays autocross. Last night was pretty cold. It cranks and cranks but doesn't even sound like it wants to catch. I may have flooded it too.

Can someone give me some advice on how to make this an easier process? Since I could not get it to go today, I have to also be concerned that there is something wrong with it. It looks like it has the choke still installed and it is functional. I have not used that in the past.

Please help, I really want to run it this weekend, not my wife's car.

Thanks

mar3

iTrader: (8)

Read these two threads and you may see the information you're looking for specific to your problem...

Mario III

The threads:

https://www.rx7club.com/new-member-rx-7-technical-256/not-starting-803749/

https://www.rx7club.com/new-member-rx-7-technical-256/1980-rx-7-wont-start-862775/

Kentetsu

First thing I would do, just to get it started, would be dump a couple of ounces of Seafoam down the primaries of the carb. That will usually get them de-flooded and running.

Once it is up to temp, check the timing, which could very well be the cause of the hard starting issue.

You may also want to make sure that the idle speed and mixture are correct. Assuming you have a stock Nikki carb, take a look at the Tuning section at Sterling's website: www.sterlingmetalworks.com

Best of luck.



.

nbs2005

So I tried the plug clean up, seafoam and oil in the carb, and some gumout and starter fluid for good measure. I got it to kick over and run for maybe 15-20 seconds, then it would stop when it ran out of stuff to burn. I'm now guessing that the carb initially flooded the engine right before it gave up the ghost and stopped working because it seems like it's not getting fuel.

I'm going to check the filters and lines to see if I'm getting gas to the carb. If that looks good, time for a carb rebuild or just rebuilt one from Sterling.

Thanks for your help and encouragement. Any further suggestions are appreciated.

Kentetsu

Can you see fuel when you look through the little windows on the front/back of the carb? Should be about halfway full.

mar3

iTrader: (8)

Carburetor isn't the problem, fuel delivery is and that's going to be a lot of fun on an '85 because it has the fuel kill circuit that keeps the electric pump off if it "sees" that the engine isn't actually running. That was introduced in 1984.

Under the car, right next to the driver's side rear tire, you'll see a splash shield bolted to the body and frame rail...does that fuel filter look like it's got "fresh" fuel in it or does it have a "rusty" look inside? You may have a gas tank with rust scale that is clogging the pick up tube inside the gas tank so fuel can't even reach the fuel pump.

Kentetsu

Mario

Checking for fuel in the float windows would determine if it were the delivery system (if empty) or sticking float needles in the carb (if they contain fuel). If they are empty then it could also be a bad trailing ignitor. Just a very simple way to gather some information for troubleshooting.

Anyway, that's just would I myself would look at before I actually crawled under the car.

nbs2005

Hey guys, thanks for the help. When I get a moment to look at her again, I'll let you know what I find.

nbs2005

Ok, I'm stumped. The float shows half full, so I assume that means the pump is getting fuel to the carb. When I add a little oil and a shot of start fluid, it catches right away and then dies a few seconds latter. When I work the throttle from the carb I can see gas shooting into the the carb.

Where do I go from here? Could it still be a fuel flow issue from the tank to the carb? Is the carb the problem?

Thanks for your help.

25yrfan

Had a similiar problem with mine. It was starving for fuel. Mine had sat for a number of years. I had replace the gas tank back in 2001, but had not worked on it since. I recently replaced the fuel filter and the pump but was still having the same problem. I dropped the gas tank and found it did have a fair amount of rust in it.

There is another filter inside the gas tank, it is a round plastic piece that fits over the fuel pickup tube. It uses a very fine mesh screen in it and mine was getting clogged with rust.

I just got a gas tank restoration kit POR-15. It comes with Marine Clean that will get rid of the sludge build up, an etching solution that will disolve the rust and leave a zinc coating on the inside of the tank for the last step, which is to apply the sealer. Then no more rust!

I plan on keeping this car for a long time and don't want to deal with this again.

infernal

W000t! How are these two connected???

Kentetsu

1984 & 1985 added a safety measure. If there is no spark on the trailing ignition, then the fuel pump will not run.


Okay, so you have fuel in the carb, but it isn't getting into the motor. That would definitely point to sticking float needles. You can rebuild the carb, or try a shortcut:

Remove the air filter housing, and use a plastic hammer (or something similar that won't damage the carb) and bang on the top of the carb a few times. The goal is to "shake loose" the float needles. Once they are loose, they should begin doing their job, which is feeding fuel into the engine to keep it running.

Good luck. And please post back with results....

infernal

Thanx a lot for the info!

nbs2005

So I banged on the carb, nothing. It's doing the same thing, fires up real easy but only runs for a few seconds. Looks like it's time for a rebuild,a Sterling, a Holly, or a Weber.