I will begin by saying that I know there are other threads about this but I have read them and they did not help. I have a 1986 RX7. I rebuilt the motor and I cannot get it to start I’ve triple checked the timing. I know I have spark and fuel pressure. I’m using an Optima red top with 850cca and I can’t manage to get it to start. It keeps flooding and I keep purging it. Ive tried two stroke oil in the spark plug holes and adjusting the timing but nothing. It cranks and occasionally fires but wont start

 

are you re-using rotor housings with new apex seals? This is kind of the worst case and will give very poor compression until everything wears in. Assuming everything is hooked up right, you have fuel and spark, i'd pull start the darn thing and see if you can get it to fire up.

 

yeah i am. They are in pretty good shape though. Ill try that later today. Thanks

 

looks can be minorly deceiving. They may not have any deep grooves or major chrome flaking, but still have some "cupping" or bow to the surface making them not as flat as your new apex seals. This or course makes a nice place for compression to blow by. As your apex seals wear in, they will develop the same curvature which will reduce the blow by area and increase compression.
Have you done a compression test to make sure you don't have a stuck seal or anything? "Funny" story...I rebuilt an engine once and while placing the rear rotor into the housing one of the corner seals popped out and must have gone out the exhaust port. I had no idea it happened and built the rest of the engine. Motor spun over fine after stacking it and checking end play. Had a heck of a time starting the motor and ended up pull starting it. After that it would start on its own but would flood easy. Eventually pulled the motor and tore into it and found the missing corner seal. To this day I'm still a bit stumped as to where it went during the initial build. The point being I now do a compression check before I install the engine to make sure I didn't bugger something during the build.

 

wow. That’s crazy haha. I don’t have the mazda compression tester but I’ll just look for three bumps with a normal one. Thanks again for the help.

 

yeah, that's all i do, just make sure that the check valve on the tester is depressed the whole time you are cranking.

 

Pull start worked but now a new problem. Coolant overflowing out of the fill funnel.

 

Try a pressure test, it could be coolant seals or just overfilled.

 

im bringing my tester home today. I suspect an air bubble

 

Yea those can be hard to get out without one of those high funnels

 

i was using one. But I think i was filling it too fast. I don’t think its a coolant seal because it was running really well and it wasn’t foaming. Could just be wishful thinking though