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-   -   Engine coughs under load--HELP (https://www.rx7club.com/build-threads-294/engine-coughs-under-load-help-1107653/)

CobraSteve 11-19-16 10:03 PM

Engine coughs under load--HELP
 
This is my first thread request and hopefully I'm doing this properly...please bear with me. I have installed a Weber 45DCOE on my Lola replica which has a 13B engine. Last year had a short (60-second) fire due to a loose fuel line and decided it was time to ditch the turbo, fuel injection, and ALL engine management systems and get back to a BASIC engine. My documentation is conflicting as both 1988 & 1991 are listed for the engine year. I know it is a 13B (cast into the rotor housings) and it had an intercooler. Have also replaced the crankshaft angle sensor with a previous generation distributor, but cannot get the engine to respond when mashing the accelerator down. RPMs will build up if I gently apply throttle, but engine coughs and sputters. Have checked and re-checked the timing and yes, I'm pre-mixing my fuel (100:1). Any suggestions out there, please?

clokker 11-20-16 11:09 AM

You'd probably get more views down in the general section but since I'm interested in the carb conversion myself, I'll jump in anyway.

Seems like you have two logical areas to concentrate on, the ignition and the carb.
Since the engine apparently runs, the basic distributor system must be right but what about the advance?

Is the carb jetted for your altitude (whatever that is)?
Is the carb in known good working order?

CobraSteve 11-21-16 10:26 AM

Response
 
Thank you for your suggestions. I concur the problem is either fuel or electrical. The only answers I can provide is the following:

1) I was assured by the supplier (rotary expert out west) of the brand-new wrap-over intake and carburetor should be set for a simple "bolt-on" without any jetting required, but I may have to invest in a set of jets from Weber and perform my own tweaking.

2) Regarding the distributor, it too was purchased new from the same source. When I saw and inquired about the two vacuum advance pots on the side of the distributor, I was told to ignore them as the mechanical advance within the distributor would do the job of advancing the timing.

Tonight I will pull my file (it is growing!) and contact the supplier of these parts and ask them for their thoughts. The engine seems to run very well with plenty of oil pressure and no smoking.

By using the Weber 45DCOE, I had to run a mechanical cable for the choke and one from a Triumph Spitfire worked perfectly! It was an absolute necessity to aid in starting the engine from cold. Initially I was surprised how hot the exhaust manifold got but after reading some blogs, this appears to be normal.

TonyD89 11-21-16 12:41 PM

Go to "Naturally Aspirated" section of the "Rotary Car Performance" sub-forum on this site. There are a few threads from guys dealing with carbing their cars and your problem seems to be common. I think you will find a lot of information to help you in that section.


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