ok i have a 79 rx7 and have had it for a lil over a year so im new to the whole rotary thing and i have hit a brick wall. it sat in a junk yard for 7 years becuase they did a motor swap and couldnt get it to run so they parked it and left it. anyway, i got it and worked on it for quite a while and got it to run, drove it around the block, u know the usual, and i only get to work on it on the weekends and i would crank it up just to get it running but it would always take forever to get it to crank up, id have to constatly charge the battery and give it a boost and pour gas in the carb (its a 12a). and id let it get warm and then cut it off and try to crank it write back up but it never would. what do yall think is keeping me from just turning the key and firing it up? timing maybe? also does it take a lot of juice from the battery to crank these motors up? it seems like when i go to crank it up it aint no time and the battery is dead. any info on lil things to tinker with are welcome, like i said, ive hit a brick wall....

 

Possibly a bad ground on the starter wire. I upgraded mine with 4 gauge wire (positive and negative) to the starter. havent had problems yet, but alot of people seem to and this is how they fix it. Just go to walmart and buy a 4 gauge car stereo amplifier kit and that will be more than enough needed. Cost is about 20-25 bucks. If it doesnt fix it, then at least you know you wont have to worry about the wires.

 

Does it have the stock ignition system, ie, points? Have you done a compression test on the engine? No it does not take much amperage to crank these motors over. If the engine turns very slowly, then take the battery and have it tested and take the starter out and have it tested for amperage draw. This is of course after you check the wiring for porper ground and for corrosion at the terminals. If all is fine with the starting system and battery, do the compression test, if it's low, around the 65-80psi range, do the mmo thing and let it sit for awhile, then fire her back up. Remember these engines rely on cranking compression, turning too slow
or low compression in one housing even will make it a bear to start. rx7doctor

 

ok, that gives me something to start with. yes it still has points, original points actually. no i havent done a compression check. i have a compression gauge for a piston motor but it doesnt work with a rotory, do i need to buy a rotary compression gauge? like i said i have to boost the battery so i know it is spinning fast enough.

 

Maybe you starter is drawing to much current. Have you checked to see how much fuel you are getting. Plugs and wires? Ignitors? Is your choke working?

 

you can use a piston engine guage just remove the schrader valve outta the end and watch each pulse while someone cranks it. the schrader valve is the little thing in the end like a tire valvestem has in it....the same tool works for it.

 

If you constantly have to jump that battery, then it is no good. Make sure when you jump start it that you put the jumper ground lead to a good spot other than the battery on the vehicle being jumped. Also you need to start by changing the
points, conenser, cap and rotor. Test the ignition leads. No you do not need a
compression tester for a rotary unless you have about $600.00 to spare. You just remove the valve stem where you depress it to release the reading. this allows you to see a variation in the cranking compression to get an idea of the condition of all 3 sides of the rotor. You dont have to do it this way to get a feel for whats going on inside the motor. If you check the back housing for instance with the valve in and all you get is 75psi or lower, you typically have a worn engine. rx7doctor

 

well, i got new plugs in it and im getting good fire, i do plan on changing out the points. yes the choke works fine and i am gettin plenty of fuel. ill be sure to check the compression next chance i get. so all i do is take out the valve and spin the engine? if its below 75 the motor is shot or what?

 

Does not mean its had it, but could have alot of carbon lock. rx7doctor