www.RX7fb.com

Another obvious thing - is the fuel return pipe connected from carb to Tank & was the fuel filter connected as per the In/Out arrows?
Also perhaps a picture(s) ot the whole engine from above & sides as maybe some eagle eyed member might see something.
Very hard to diagnose from a distance. There will be quite a few at Castle Coombe on Saturday, might be worth having a look at the different engine setups & taking pictures for reference regarding blanking plates etc
There is a RX Guru Tim White @ RX Motors in Salisbury.

Well I am sure I replaced the fuel filter correctly and it was of the right type. The fuel return too and indeed you can hear the fuel returning into the tank and see it flowing through the clear temporary fuel filter when the ignition is one engine not running.
The more I think the more I suspect carb/associated parts. Building up the revs in neutral it flutters and has unstable revs until high up (probably when the 2nd barrels come in) when it takes off and revs smooth.
Also fast blipping it the engine is smooth because it gets a squirt of fuel from the accelerator pump perhaps.

You did have checked the two filter before the carb needle?

viewtopic.php?f=4&t=1118&start=120

I have, both were falling apart and broken so removed! Have the extra filter just before the carb at the moment. The car runs wrong early in taking up power so I do not think it is furl delivery ad such, if it was it would usually be good for a bit until the float bowls run dry. I think I may pull the carb again.

rustyrescue wrote: ↑Wed Jul 06, 2022 9:56 pm

KiwiDave wrote: ↑Wed Jul 06, 2022 9:32 pm

rustyrescue wrote: ↑Wed Jul 06, 2022 7:21 pm Hi, I will take a picture of the carb and try to work out how to post it haha!

A lot of us use Imgur. Upload your pics, select the BBCode option and paste into your post.

I was impressed I managed to attach pics at all!! my IT skills come from an age of the cars and bikes I play with I will look at your suggestion.

What coils should I fit as replacements? for relatively little outlay it would replace the originals.

I can sell you tested good used 1st gen coils for £15 each plus shipping if you need them but before you buy replacement coils, try swapping the leading coil for the trailing coil..... it will run ok if the trailing coil is bad but not if the leading coil is bad...... the leading coil must be working fine.

I can sell you tested good used 1st gen coils for £15 each plus shipping if you need them but before you buy replacement coils, try swapping the leading coil for the trailing coil..... it will run ok if the trailing coil is bad but not if the leading coil is bad...... the leading coil must be working fine.

Thanks, good tip, I will switch them tomorrow! cleaning terminals at same time. It sort of runs ok, until you drive it! I thought it was all good.....it was awful when we got it and either stalled or raced until the carb was stripped and looked at!

I just suspect its carb related, or air leak perhaps. But as said, am not rotary expert so not sure how they sound when wrong or indeed right!

coils switched and no difference, the more I run it the more like carb it seems to be?
blip engine quickly it sounds good.
Build revs up quickly it sounds good.
Both these accelerator pedal actions would inject fuel from the pump on the carb.
Build revs up slowly though and try and hold a steady rpm and the revs waver, falter and drop/rise again.
That said I can feel a little vibration through the car when it is misbehaving and not sure a rotary misfire would sound/feel like a piston engine.
Will take carb off again and look, dont have another one to try other than a damaged in the post parts carb.

A thought though, would the janspeed manifold and exhaust cause it to run lean? need jetting up? like my bikes. Standard air filter though on this. Plugs are decent colour but it gets warm when trying to drive holding fine idling/stationary.

When it’s missing and playing up, what happens if you pull the choke out? If stabilises things then you are probably running lean due to a vac leak

Just a thought but are the secondaries opening ? I had a similar problem when I had my carb rebuild.

rustyrescue wrote: ↑Fri Jul 08, 2022 5:20 pm A thought though, would the janspeed manifold and exhaust cause it to run lean? need jetting up? like my bikes. Standard air filter though on this. Plugs are decent colour but it gets warm when trying to drive holding fine idling/stationary.

No, nothing to do with the Janspeed system. Sounds like a vac leak or maybe the idle circuit in the carb, possibly a combination of both?

If you can post some pics of the carb, that would help with diagnosis. There is a plate that sits between the carb and the inlet manifold. it has a number of vacuum hose connections. Any that are not connected need to be capped.

Tim White at RX Motors should really be your first call.