first'one

I've got a '78 GT with the 12a engine which has been stood for quite a while, i've finally got round to starting it after changing all fluids, fuel, oils, distributor cap, fuel filter etc. It started but ran real rough a wouldn't tick over, i messed with the mixture screw and got it ticking over but it sounded pretty unhappy. i've come back to it today and it won't start at all and now it seems like at least one of the plugs is no good.
I rang the Mazda dealer who said i should have 2 different types of plugs in it 2 for the lead plugs and 2 for the trailing plugs, is this correct?
Could the rough running be down to anything else or could it just be a matter of carb set up?There doesn't seem to be any air leaks anywhere but i've looked in the manual and there seems to be a real complicated emissions set up of pipes, relays and valves which i just can't figure out, could any of these cause my problem?For a 1978 car it does seem to have a preety complicated set up.
Plus the rev counter just seems to show the volts not the revs, why should that be.
Please help, i've been looking forward to getting the car on the road but i keep getting more problems.It needs to be driven.

my84gslrx

I and most people just run br8's or br9's in all four, never gave me a problem

orion84gsl

iTrader: (5)

I know I use and Mazda recommends using the NGK BR8EQ-14 in all four. If it's a stock engine you do not need seperate plugs for leading and trailing. Your carb may need a rebuild after sitting that long, which would definitly be the cause of your problems. It's not expensive if you do it yourself and have the know how and time to put into it. It is expensive if you pay someone to do it, which may or may not be worth the money to you. Also recheck your fuel filter. I know you said you changed it but with the car sitting that long more crap from the gas tank could have easily clogged the new one after you got it started.

I will now direct you to www.sterlingmetalworks.com check out his stuff. I'm running one of his carbs and know of a couple other people that couldn't be happier with theirs.

first'one

Thanks for the link, very interesting although i think it would be to expensive to send over from Ireland and i notice he doesn't have a Uk shipping price listed.
Do you know how many bits i can throw away off the carb?

mazdaverx713b

iTrader: (91)

BR8ET's were the oem plug in 79 but you can use the BR8EQ14's

first'one

Thanks for the advice, i've just bought 4 BR8ET's.
Looks like the old ones have been in since birth, so probably about ready for a change. Would you believe i couldn't get them anywhere in Ireland, had to order from the Uk.

David Dewhurst

iTrader: (2)

***the 12a engine which has been stood for quite a while, ***

***It started but ran real rough a wouldn't tick over, i messed with the mixture screw and got it ticking over but it sounded pretty unhappy.***

The above two items may indicate some stuck rotor seals. I don't have a clue what you mean by "tick or ticking". Pour some automatic transmission fluid down the small holes in the carb while a friend is turning the motor over with the key/starter. Let the motor sit for a couple days & then try to start the motor. The automatic transmision fluid will free up any stuck rotor seals. If this helps, when the motor starts it will smoke everyone out of the area. < That's normal untill the automatic transmission fluid burns out of the motor.

***Plus the rev counter just seems to show the volts not the revs, why should that be.***

Might this ^ indicate a bad coil?


*** i've come back to it today and it won't start at all***

It could be a coil or both coils are bad or it may be the rotor seals are not extending & there is no compression.

You do not require two different spark plugs.

first'one

Thanks David, There's 4 pots on the carb which ones should i put the oil into?
Is there any way to test the coils? which one is the leading coil which one is the trailing coil?
This is my first RX so its all a bit alien at the moment, i don't suppose it helped getting one that had been stood for so long, but it was cheap.

DivinDriver

iTrader: (15)

Most people around here recommend SeaFoam instead of ATF (easier on the water seals & formulated specifically to be burned, is the argument) but I'm not sure if it's available in Ireland.

The two bores (pots) closest to the centerline of the engine are the primaries, but it doesn't matter greatly so long as you treat front and rear. Open the throttle fully before adding, so you get better access.

first'one

No i can't get seafoam here so the ATF will have to do, i'm going to take the carb off and de-clutter it at the same time, emissions isn't a problem here for older cars.
I'm desperate to get it on the road but keep coming up against little problems, but i'll get there and i'm sure it will be worth it .

DivinDriver

iTrader: (15)

It'll definitely be worth it; I just finished an 8-month effort to end a 3-year hiatus. Fun!

David Dewhurst

iTrader: (2)

first'one, I'll do the best I can with the coil help.

The most forward coil should be the "trailing" coil. The trailing coil should have a black wire with white stripe attached to the positive terminal & a yellow wire with a green stripe attached to the negative terminal.

The rearward coil will be your "leading " coil. The leading coil should have a black wire with a white stripe attached to the positive terminal & a yellow wire with a blue stripe attached to the negative termanial.

The hight tension wire from each the trailing & the leading coil should travel from the respective coil to the distrubitor cap where identified with a "T" for the trailing high tension wire & to the distrubitor cap where identified with a "L" for the leading high tension wire.

The resistance of each coil high tension lead when measured with an ohmeter should not exceed 16,000 ohms +/- 40% per 1 meter of lenght of wire.

The forward rotor is the # 1 rotor & the rearward rotor is the #2 rotor. The upper plug of each rotor is the trailing plug & the lower plug of each rotor is the leading plug. If I remember corrctly the rotor cap is identified which location each plug wire travels/attaches to.

When the coils are at operating temperature (hard to get the coil to temperature when the motor will not run.) check the primary resistance with an ohmeter. The ohmeter should read 1.35 +/- 10% ohms on both the leading & trailing coil.

Hope this supports your effort.

If I'm in error with any of this information one of the US Yanks will jerk my chain.

first'one

Thanks David, you've been very helpful.I'm going to takle it tomorrow.
I'm going to put the oil down the carb and leave it until tuesday when i'm hoping the new spark plugs will arrive.

David Dewhurst

iTrader: (2)

firts-one, try starting the motor with the old plugs to clear out the automatic transmission oil. If it will not start with the old plugs give it a try with the new plugs because they will burn clean. Also I forgot to mention that the yellow wire with green stripe from the negative terminal of the trailing coil travels to the tachometer.

RX-S7V7N

Hello, i get my 1985 RX-7 Last week with that same engine, and in my country that spark plugs cost about 40 Euros each one, can you tell me were you buy yours and what price?