MFI: cleaned t-stat - runs worse

[donk]

Hi all,
Last weekend I cleaned the gunk out of my MFI thermostat. When I reinstalled it, the car was difficult to start (the cold start solenoid is not connected) and even harder to keep running. When I gave it more gas, it would die. After a few minutes of restarting, it started to get better. It would finally idle good, but still sputtered and/or died out when I gave it some gas. Eventually, I let it idle for awhile and as it warmed up, it ran pretty well. I took it for a short drive around the block and it seemed ok, but still worse than it was before. I haven't had alot of time to look into it yet, in fact, I haven't tried to start it since then. I was just wondering if any of you MFI gurus had some words of advice for me before I start digging into it.

Thanks

[Tyson Schmidt]

That's because the thermostat is now finally working properly and leaning the mixture out all the way. Someone likely had adjusted the mixture in the past to compensate for the sluggish t-stat that was keeping it too rich.

Now that it's working properly, you need to richen the mixture. Turn the main rack one click counter-clockwise at a time until the car runs well at around 3000 rpm cruising in 2nd or 3rd gear and doesn't buck or lean surge.

[ed martin]

Yep, just like Tyson said, but don't adjust more than a few clicks at a time and not when the engine is running. Also there's some good technical resources here regarding this topic and you may want to get a copy of the Check, Measure and Adjust Manual. Better yet, If you have someone who is familiar with the system and can adjust it using a dynometer to set the CO level, that would be optimal. To do it correctly the level needs to be checked under load.