Impco 225 Adjustment
 

I was just wondering if anyone has any idea how to lean out the 225 Mixers? I am running one on a 1.6L 4 clyinder and the power is just insane compared to the same engine a couple days ago when it was on gas. But it is way rich at idle and i'm guessing off idle because I got it off my old 302. Using an Impco Model E regulator as well.

I was taught...
 

I was told to adjust the idle by turning the idle screw until a very gentle press on the primer button of the regulator won't make the enine speed up or stumble.... As for power mix adjust it all the way rich and start cranking it back till the power is at its max....

The Idle Mixture will really screw up the way ot runs, it will almost die or lope really bad the more I turn it out but it will run with it all the way in, go figure. I was told to make some thin shims to go under the gas valve i think it was.

hey guy's,i was wondering if you know where i can get any book's on automotive proane.a book that tell's how to set-up,install and tune propane.thanx/scott.

also check that the regulator is only letting out gas while the engine is running, you should be able to here it hiss. On my 71 Ford I had to rebuild the regulator before it would run right....

Too rich of a setting will result in low power just as quick as to lean---ideally you should set the mixer based on a electronically controlled sniffer in the exhaust. I never had a "sniffer" but always checked out pretty good against the sniffer based on holding a steady load on the engine and maximizing the rpm by adjusting the load screw (big screw)----this is alot easier done with an auto transmission than standard transmission and clutch (with a standard transmission you will need someone to either drive pulling a load or ride the clutch for you----but keep a very steady load so that you can tell what your adjustments are doing). Use a handleld tachometer if available.

The idle setting will not have much effect on total power----best way to set idle, again is to maximize rpm while adjusting idle screw (small screw). When rpm is maximized---engine should start imediately with little to no throttle opening.

As stated in one of the above postings---you should not have any gas passing through the regulator without the engine running. Vacuum cracks the diaphram in the regulator (vaporizer) once the engine is running----a leaking regulator will result in excess gas flow (flooding) and thereby preventing you from ever getting a true setting. With everything off---you should not be able to smell any gas. I have had them leaking to the point that you could hear, smell and see the leakage.

I have run both 225 and 425 mixers----I ran the 225 on a 327 V8 Chevrolet in a Massey Ferguson combine----the 225 may still be too large for your small engine application??? Ran 425 in larger applications.

I always found that lack of air was the biggest limiting factor effecting power on the L-P setups (running to rich, or flooding)----use a big volume air cleaner and keep it clean so that you can keep plenty of air coming to the intake.

Just noticed your question----passing on a few of my thoughts. Good Luck!!

Delta Dirt

hmm, I think it may be the regulator then, I'll have to look at replacing it. as for power, it will rev past 8000 rpm, it will pull pas 140 km/h now, couldn't do that when it was on gas. But the idle is crap, so i will check the regulator as I actually have to lift the diaphram (sp) on the mixer to let more air in to start it. opening the idle mixture screw just makes it idle rougher and try to die more.