Search found 1063 matches

by C3H8
Wed Jun 17, 2020 6:22 pm
Forum: Propane Forum
Topic: Idles at 1250 RPM
Replies: 4
Views: 207

Re: Idles at 1250 RPM

The mixer size is fine. There is usually only one reason an engine idles fast. You have a vacuum leak somewhere downstream of the mixer. Barring that on rare occasions a sticking or loose throttle plate. I would say 90% chance of a vacuum leak. Start looking for a sucked in intake gasket, throttle p...
by C3H8
Sun Jun 07, 2020 5:25 pm
Forum: Propane Forum
Topic: Propane fuel level gauges
Replies: 3
Views: 115

Re: Propane fuel level gauges

We don't know where "Near me " is, however there have always been 2 manufacturers of junior gauges in North America. Rochester and Squibb. Rochester was the most common, probably used in 90% of the conversions. The Rochester and Squibb are not compatible with the in-tank assemblies of each other. Th...
by C3H8
Tue May 26, 2020 9:21 am
Forum: Propane Forum
Topic: 2 300a mixers on 1 modelE evaporator
Replies: 2
Views: 129

Re: 2 300a mixers on 1 modelE evaporator

It's not a matter of feeding the setup. It tied to the demands of the engine. A stock 390 has various HP designs depending on what it was used in. Examples, it was used in large Ford trucks with cams designed for good torque at 2500 to 3500 RPM. In cars like the Ford LTD it was set up for good cruis...
by C3H8
Fri Apr 24, 2020 1:58 pm
Forum: Propane Forum
Topic: 454 turbo impco 425 x2 tuning help
Replies: 20
Views: 1112

Re: 454 turbo impco 425 x2 tuning help

425 mixers only have adjustments for idle and wot. The midrange is controlled by the taper of the gas bullet based on the current airflow. Airflow increases the bullet (air/gas valve) lifts higher allowing more fuel. The midrange can be changed by replacing the air/gas valve with a leaner or richer ...
by C3H8
Mon Apr 20, 2020 2:06 pm
Forum: Propane Forum
Topic: 454 turbo impco 425 x2 tuning help
Replies: 20
Views: 1112

Re: 454 turbo impco 425 x2 tuning help

My error! I just enlarged your photo and see you are piped into the adaptors on top of the mixer already. The system you have should work ok as a balance line. Like you mentioned I prefer not to use 90 degree fittings, however they are available in a formed pipe rather then the style you have. There...
by C3H8
Mon Apr 20, 2020 2:01 pm
Forum: Propane Forum
Topic: 454 turbo impco 425 x2 tuning help
Replies: 20
Views: 1112

Re: 454 turbo impco 425 x2 tuning help

My knowledge of turbo's is limited, however I can see two issues with your system to check out. I would not use the balance port on the 425. It's a 1/8" NPT which means an opening of only about 1/4 inch which you then enlarged to about a 5/5" line. You should pipe those balance lines directly into t...
by C3H8
Mon Apr 13, 2020 3:27 pm
Forum: Propane Forum
Topic: Lean out at WOT. Fine at 3/4 throttle
Replies: 18
Views: 947

Re: Lean out at WOT. Fine at 3/4 throttle

I must admit to a little frustration here. Lean conditions have a specific process to figuring them out. I made some suggestions earlier and from what I can tell it appears you haven't checked the basics. You keep going back to the mixer and ignoring the process. I'll repeat the process. The system ...
by C3H8
Sat Mar 28, 2020 1:35 pm
Forum: Propane Forum
Topic: Lean out at WOT. Fine at 3/4 throttle
Replies: 18
Views: 947

Re: Lean out at WOT. Fine at 3/4 throttle

Regarding Having 2 fuel tanks in the trunk, I could disable one or the other, to rule out any tank-related issues. Unless you have sperate hoses from each tank going all the way to the engine compartment switching tanks will not reveal if there is a collapsed inner liner in the hose. That's why I re...
by C3H8
Fri Mar 27, 2020 6:24 pm
Forum: Propane Forum
Topic: Lean out at WOT. Fine at 3/4 throttle
Replies: 18
Views: 947

Re: Lean out at WOT. Fine at 3/4 throttle

Further to my previous response. The fact your mixtures are leaning even sooner now points to one of several problems. 1. The primary seat has separated from the backing and is plugging the vap inlet. 2. Problem with the lockoff or filter (you say you checked those already. 3. Collapsed inner liner ...
by C3H8
Fri Mar 27, 2020 6:16 pm
Forum: Propane Forum
Topic: Lean out at WOT. Fine at 3/4 throttle
Replies: 18
Views: 947

Re: Lean out at WOT. Fine at 3/4 throttle

You don't have to take it all apart. The foam filter is unlikely to cause this. It's main function is to trap liquid LPG on start up which is then released as the vapourizer warms up. To test the vapourizer to see if there is an issue with it or somewhere before it you need to put a pressure gauge o...
by C3H8
Sat Mar 21, 2020 1:26 pm
Forum: Propane Forum
Topic: L67 LPG options?
Replies: 2
Views: 672

Re: L67 LPG options?

If I understand your question correctly the Gann/impco adaptor for dual 425's vertical mount is AA3-80. Several are available on Ebay.
by C3H8
Mon Mar 16, 2020 1:06 am
Forum: Propane Forum
Topic: Dual carbs with propane?
Replies: 25
Views: 7672

Re: Dual carbs with propane?

Thanks for the compliment storm, appreciate it. To clarify the valve build up issue. True story about a first generation 300 CI Ford (long time ago, 1980's). My dealer called me because a customer lost power on his engine. approximately 10,000KM's on it. When I got there we did a compression test an...
by C3H8
Mon Mar 16, 2020 12:52 am
Forum: Propane Forum
Topic: mkiv 454 big block and impco300 mixer too small?
Replies: 7
Views: 1635

Re: mkiv 454 big block and impco300 mixer too small?

A 454 only flows 450 CFM at 4500. Not an exact number. On over the autos the preference is to over carburate slightly. In other words the 425 mixer would be close to ideal unless your wot operation is over 5000 RPM and you say you top out at 4500. The 300 50 series is marginally small. Either way if...
by C3H8
Sat Mar 07, 2020 2:04 pm
Forum: Propane Forum
Topic: Dual carbs with propane?
Replies: 25
Views: 7672

Re: Dual carbs with propane?

HI everyone, I was beginning to think we had all disappeared. Nice to see all the feedback. I'm going to clear up two things. The Ford 300 F150's in NA have a longer stroke then bore as far as my old memory can remember. I decided to look it up and storm is actually correct. The bore and stroke are ...
by C3H8
Thu Mar 05, 2020 7:03 pm
Forum: Natural Gas Forum
Topic: CNG Advance curves vs LPG or 'The Liquid' with a classic
Replies: 3
Views: 5559

Re: CNG Advance curves vs LPG or 'The Liquid' with a classic

I should have also mention that the curve you attached is typical, however you can see their example indicates what I was talking about. At WOT their curve shows about 12 or 14 degrees advance on petrol at 2500 RPM. The NG curve it topped out at approx. 38 degrees. In these cases the vacuum advance ...