Car sat 3 years but had fresh fuel with stabilizer each year.

Car was driven 10-15 times each year but only to the point that engine was fully warmed up, 4-6 miles country driving, depending on weather.

Car has new plugs and all new hi-test gas.

Starts perfectly cold. Won't start after being driven and thoroughly warmed up, 20 minutes say, temp guage at 1/2 point.

Also seems to develope some weakness in the idle after idleing perfectly for 3-5 minutes. Drops off of the good strong idle to a weaker one.

Where is the problem?

Martin

 

Do a compresion test. If it's low, try decarboning it.

 

you can search to find out how to do those with a search, and if you stillhave questions, then post up your findings! goodluck.

 

Check your ignition timing while your at it.

 

Hot start? what's that/

 

Adding to what Professor Trochoid says, compression is lower on a hot engine. If the compression is marginal cold, it will be very hard to start hot.

Also check for vacuum leaks. Hoses that fit up well cold may leak when things heat up.

What do you mean by "hi-test" gas? You only need 87 octane for non-aspirated engines.

Last, what do you mean by not starting? Does it crank at all? Crank but no fire? Fire but stumble and die?

 

More Clues!!!!

Hot doesn't mean overheated, just normal temp, straight up and down, at most, on temp guage.

I just shut down just after the choke released down. That's a warmed up engine right? The car started by using full choke and pumping the gas.

Once car starts it runs without a stumble or stutter, hard, right to 7000.

So after the restart of the warm engine I drove car for 10 minutes. Temp guage was higher, but not up and down.

No start, no way. EXCEPT I put a tablespoon of gas down the passenger side of the carb and the car started with no choke and no pedal pumping. Immediately. So I did it again 3 or 4 times, let the car run a couple of minutes, shut off, try restart with no go, add gas, immediate start.

I really think this car has a fuel delivery problem. In a previous thread I was having to prime to get the car started cold, but now it starts cold, full choke and 2-3 pedal pumps, every time.

I am thinking carb problem BUT all those vacume hoses that I know nothing about. Can anyone point out specific vacume hoses to be checked? Or is it time for carb rebuild. 121k on car but still 22 yrs old, and it did sit.

Thanks everyone

Martin

 

well nothing is really jumping out to me, maybe one of the more experienced members can help. but i think a good 'ole carb rebuild is in order.

 

Sitting is bad for carbs. The gas evaporates, leaving a varnish, plugging everything up eventually. If the carb has never been gone though, it's probably due. Good time to replace the vacuum lines while you are at it.

There is a carb manual in the archives with the other FSMs.

Hot does refer to restart at normal operating temps.

 

Neglected to say that no start means no fireing. The engine turns over fast. It has a new battery and the starter is turning the engine over as fast as it did 10 years ago.

I just add that little fuel, and it pops right off.

And now, after cooling for 45 minutes, it started immediately with no gas added, just full choke, 1/2 a revolution on the starter, good to go.

 

Still sounds like low compression. Run a can of Seafoam though 1/8 tank of fuel, run it semi-hard, see if it will loosen up the seals. Besides the carb, sitting a long time also allows the carbon build up internally to dry out, causing the seals to stick. Shows up worse on hot starts.

 

I agree. Carb rebuild + replace all vacuum hoses. When was the last time the fuel filter was changed? Good time to do that too.

 

+1 for seafoam

 

Seafoam first, then carb?

I've had the car more than 10 years but still have no idea how the engine works. I did change the oil.

gas filter was fairly recent.

 

Seafoam through the tank will clean the entire fuel system. If you run part of a can directly down the carb, pour it in till it kills the enge, then let it sit, it will help loosen the seals faster. If you pour it in the carb, let it sit a day or 2 and turn the engine over by hand backwards. That will help spread the Seafoan and keep it in the engine.

When you go to restart, add a capfull of motor oil to each barrel of the carb.

 

trochoid

Now this is getting interesting. Does the seafoam in the carb go down one side or the other? Seriously, when I prime to start it works much better in the passenger side.

Sea foam it is. The car has over half a tank of gas. The seafoam is 50 mi round trip away. Can I drive the car to get the seafoam or would that be dangerous to the stuck seals?

I'll get a handle on this. It is just too sweet an old car to give up on. I hope to be driving it when I'm 92 and have a two word vocabulary.

I just desperately need to drive the car so I can generate some major interest in it. I can siphon the gas down to 1/8th tank easy enough too.

Does that carb have 3 or 4 barrels? I see the two on the passenger. What the hey and extra cap of oil wont hurt.

Thank you so much

Martin

 

If Seafoam is that far away you can use atf or water also. These are best used by having them drawn in by a vacuum hose. You will need to keep the rpms up and not let it die out. The atf can be allowed to sit like the Seafoam, the water won't do anything setting.

Do this outside and warn you neighbors, you sill smoking them out.

7s came stock with a 4 barrel Nikki carb, the passenger side ones are the secondaries, vacuum operated and only open under load.

 

My Dad had the same problem on his and it ended up being a bad fuel pump. He brought his car to an RX-7 guy who put a fuel pressure gauge on that he could look at while he drove it and there was no fuel pressure after the car warmed up. Just a thought when I read your post.