View single post by Judson Manning
 Posted: 07-17-2006 05:53 pm
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Judson Manning

Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Everyone has different experience and what I've found is every engine seems to like a different jetting.

The spitting comes from fuel dropplets dripping on the hot intake valve and exploding when it is closed.  There are a number of things that can cause this problem including a leaking pump-jet, incorrectly set float, or fuel condensing on the intake manifold. 

The latter can happen on start-up when the runners are cold.  It can also happen when the mixture is way too rich.  If your carbs leak or have wrong jettings, the answer is not to add another accessory.

The Lotus Spec 9 calls out for 160mains and 57idle jets, compare that to the stock JH 130mains and 55idle jets.  The correct answer is somewhere in between.

My 2.0 ran great on 135s and my 2.2 runs great on 140s.  Are 145s or 160s for you?  who's to say, but the best thing to do is get several jets and iterate to a solution that's best for you.

BTW an EGT and/or O2 sensor makes this soooooo much easier.