Menu
Forums
New posts
Search forums
Calendar
Monthly
Weekly
Agenda
Archive
What's new
New posts
New media
New media comments
New profile posts
Latest activity
Media
New media
New comments
Search media
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Help Support Hardline Crawlers :
Forums
Rock Crawling Forums
Tech & Fab
Propane injection questions
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="altfuel1991" data-source="post: 713219" data-attributes="member: 1211"><p>I do not remember seeing if your mixer was new or not. The reason I ask is whether it has been altered or not. On Impco mixers the power mixture is preset when assembled and should not need to be adjusted. You cannot set a propane engine by ear, it is too easy to get it way too rich. You can set the idle by ear and get close though. Checking plugs will not tell you whether it is running rich or lean unless the electrode is melted off since propane burns completely clean and leaves no residue on the plugs. Realistically you cannot treat this engine like it is gasoline powered, the two fuels are completely different and the rules are not the same. I played with timing in the shop on an engine one time and kept adjusting it until it had the absolute smoothest idle and then checked it with the timing light. It had 50 degrees timing at idle. As soon as the throttle was cracked it would start detonating and shaking though.</p><p></p><p>The problem might well not be the fuel system at all. There was no mention of how the engine is timed and that is critical on propane. High timing has a hugh effect on creating too much heat in the engine. The cooling system also needs to be in peak condition. Other factors such as a high compression ratio require greater cooling.</p><p></p><p>Here are guidelines for setting the timing on a propane engine.</p><p>On most applications, the timing should be a total of 30 degrees(base and centrifugal) with all of it in by 2500 rpm. What we normally do is disconnect the vacuum advance, run the engine up to 2500 rpm, set the timing at 30, lock it down, then let it idle with the vacuum advance disconnected. See what your base timing is running. If it is low,4-10 degrees for example, you can alter the centrifugal to lower that number and increase the base, still keeping a total of 30 degrees. As you increase the base timing check to see if the engine spins and starts smoothly when hot. If you reach a point that the engine bucks or loads the starter, back off about 3-4 degrees and that is your base timing. Subtract that number from 30 degrees and that will be the advance you need to have. This will provide a good start, strong idle and proper advance curve. We have had some engines run as much as 20 degrees base timing but 14-16 degrees is normal. The vacuum advance should be connected to ported vacuum and have no more than 10 degrees. This helps fuel economy at light throttle positions. </p><p></p><p>I have 27 years in the propane conversion and repair business and there are several of my systems on crawlers.</p><p>__________________</p><p>Sincerely, </p><p></p><p> </p><p></p><p>Buddy Gamel</p><p>Precision Sales & Service, Inc.</p><p>451 64th Place South</p><p>Birmingham, Ala. 35212</p><p></p><p>877-403-7827, office</p><p>205-837-8871, mobile</p><p>205-591-2267, fax</p><p></p><p> </p><p>bgamel@alternatefuel.com</p><p>bgamel@workhorseservice.com</p><p><a href="http://www.alternatefuel.com" target="_blank">www.alternatefuel.com</a></p><p><a href="http://www.workhorseservice.com" target="_blank">www.workhorseservice.com</a></p></blockquote><p></p>
[QUOTE="altfuel1991, post: 713219, member: 1211"] I do not remember seeing if your mixer was new or not. The reason I ask is whether it has been altered or not. On Impco mixers the power mixture is preset when assembled and should not need to be adjusted. You cannot set a propane engine by ear, it is too easy to get it way too rich. You can set the idle by ear and get close though. Checking plugs will not tell you whether it is running rich or lean unless the electrode is melted off since propane burns completely clean and leaves no residue on the plugs. Realistically you cannot treat this engine like it is gasoline powered, the two fuels are completely different and the rules are not the same. I played with timing in the shop on an engine one time and kept adjusting it until it had the absolute smoothest idle and then checked it with the timing light. It had 50 degrees timing at idle. As soon as the throttle was cracked it would start detonating and shaking though. The problem might well not be the fuel system at all. There was no mention of how the engine is timed and that is critical on propane. High timing has a hugh effect on creating too much heat in the engine. The cooling system also needs to be in peak condition. Other factors such as a high compression ratio require greater cooling. Here are guidelines for setting the timing on a propane engine. On most applications, the timing should be a total of 30 degrees(base and centrifugal) with all of it in by 2500 rpm. What we normally do is disconnect the vacuum advance, run the engine up to 2500 rpm, set the timing at 30, lock it down, then let it idle with the vacuum advance disconnected. See what your base timing is running. If it is low,4-10 degrees for example, you can alter the centrifugal to lower that number and increase the base, still keeping a total of 30 degrees. As you increase the base timing check to see if the engine spins and starts smoothly when hot. If you reach a point that the engine bucks or loads the starter, back off about 3-4 degrees and that is your base timing. Subtract that number from 30 degrees and that will be the advance you need to have. This will provide a good start, strong idle and proper advance curve. We have had some engines run as much as 20 degrees base timing but 14-16 degrees is normal. The vacuum advance should be connected to ported vacuum and have no more than 10 degrees. This helps fuel economy at light throttle positions. I have 27 years in the propane conversion and repair business and there are several of my systems on crawlers. __________________ Sincerely, Buddy Gamel Precision Sales & Service, Inc. 451 64th Place South Birmingham, Ala. 35212 877-403-7827, office 205-837-8871, mobile 205-591-2267, fax bgamel@alternatefuel.com bgamel@workhorseservice.com [url=http://www.alternatefuel.com]www.alternatefuel.com[/url] [url=http://www.workhorseservice.com]www.workhorseservice.com[/url] [/QUOTE]
Insert quotes…
Verification
Post reply
Latest posts
Golden Mountain Off-road Park opening
Latest: ridered3
Yesterday at 9:02 PM
General Discussion
I am moving to Tennessee
Latest: hokie_yj
Yesterday at 7:45 AM
General Discussion
For Sale
2005 Ford Excursion Eddie Bauer
Latest: jeeptj99
Monday at 11:55 AM
Vehicles For Sale
I.w.i.w clampy
Latest: bobbedrunner99
Apr 26, 2024
Tech & Fab
Salvage 10
Latest: ridered3
Apr 26, 2024
Tech & Fab
Forums
Rock Crawling Forums
Tech & Fab
Propane injection questions
Top