Propane help

ol'Jeeps

ol'Jeeps

Dirty Jeeps...Done Dirt Cheap!
Joined
Dec 5, 2006
Location
Hickory, NC
Hey any of the Propane gurus on here. I just replaced the 425 mixer on my Yellow Jeep, it went from very easy to start. (Even after sitting for several weeks! Cold start was a 10 to 20 second crank time. Then once started, about a half a round crank and it started!)

After sitting for a couple of hours..or over night, it now takes at least two or three 30-45 second cranks and opening the throttles slightly to get it to start. Runs better than ever once started. Seems to start okay once it has been started...as long as I don't wait several hours! Only change has been replacing the mixer with a new one. I have checked for leaks, tested and made sure converter and lock off were working good.

Any good suggestion? (before I burn up a starter!)
 
Vacuum leak. Did you put a new gasket under it?
 
Is it bigger then your old one when I went to a larger unit it takes much more time to get it primed up but is pulls much better running

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Everything the same. New gaskets when installed. All checked for external vacuum leaks.

Only change was a 14" x 4" paper element vs the Specter cone filter on the tall propane "hat". I haven opened the "balance port". From what I read, I shouldnt need that. But did have it before. maybe I shold open that up and try it?

BUCKEYE PERFORMANCE INC. said:
You know 2 forklift mechanics.
Click to expand...

Jason W? ...and who...LOL!

Got a buddy who works for Carolina handling but he says he knows nothing about 425s. They dont use em around here!
 
I would say let it sit for a little bit so you can duplicate the problem, pull the LP hose from the 425, crank it and see what it does. If it immediately puts out a large amount of LP then you need to adjust the 425. If it comes out very little and the longer you crank it look to your lock off, I am assuming you are running a VFF30 lock off.."TYPICALLY " we replace as a pair, both reg and lock off. I know you have already did it but get a spray bottle with dish soap and water and spray the whole system..
 
Like just said, propane systems can be very hard to start if rich , but may run great. I too am unfamiliar with the 425.

Check you lock off , non injected lp system lockoffs will fail to bypassing. Causing fuel to seep through to regulator and flooding system, causing the hard to start condition.. Here is good way to tell,,, unhook the tank, valve off, wait till next day, fire it up immediately after hooking up tank. If it fires right up you will know you have a flooding problem.

Nearly all lp system failures I see is failure to rich , being either regulator or lock off.
 
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Setting your idle on regulator, by listening to engine, always take regulator to lean ( engine will pull down) and richen slightly till engine idles normally . if you have a screw on the mixer on top of carb, this is also idle adjustment as far as flow and will adjust your idle speed also.

I don't know if you have it, but most lp carbs will have an adjuster that looks like an arrow under mixer on carb, this is your high run(above idle mixture).

Beware of High run lean conditions, this will cause very fast overheating, low power , and incenerate spark plugs.

Seen you in hickory today , sweet Comanche!
 
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Thanks for all the info! I havent messed with the high end adjustment. Ill recheck the propane flow and vac leaks.

Many turns "out" on the idle screw will lean it down, correct?

Yep, Jason...almost didnt recognize ya!
 
Not to hijack the mans thread but I'm fighting air leaks at my mixer. Between my baseplate and adapter. I have 2 aluminum weber plates between the manifold (22r) and a homemade adapter ( made from 2.5 inch square tube and a plate on each end drilled for appropriate bolt pattern) it's darn flat. I was running the original weber gasket, it failed the brake cleaner test. Ive tried black and grey ultra rtv, something called threebond, and cut my own cork/rubber gaskets. Everything leaks. It bolts down tight but still leaks. All suggestions welcome, this is the only thing keeping my truck off the trails this weekend.
 
Permatex grey is what I used put several 22r kits on but I always used the got propane adapter or the Nash fuel adapter

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Put a nice consistent bead of ultra gray and let set up about 30-40min then put back together and let sit at least 12hrs before running ....
 
This may make no difference but its worth a try. One of the first vehicles I ever built was a samurai that we converted to propane with a got propane kit. I never heard it from the dealers mouth but when the kit was brought to me to install I was told when cranking cold hold the throttle wide open till it fires. Out of habit doing that from that point on I've never seen it take more than ten seconds or so to crank cold or not. Fast forward 10 years to when I built the small block for my last S-10 with propane. I bought the kit used from a board member who'd gotten if from @upnover. It was very slow to crank just like you're describing but held wide open would crank in a third the time.
 
MarsFab said:
This may make no difference but its worth a try. One of the first vehicles I ever built was a samurai that we converted to propane with a got propane kit. I never heard it from the dealers mouth but when the kit was brought to me to install I was told when cranking cold hold the throttle wide open till it fires. Out of habit doing that from that point on I've never seen it take more than ten seconds or so to crank cold or not. Fast forward 10 years to when I built the small block for my last S-10 with propane. I bought the kit used from a board member who'd gotten if from @upnover. It was very slow to crank just like you're describing but held wide open would crank in a third the time.
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When I first put that system on, it was difficult to crank. Seems I remember reading somewhere that I needed more vacuum. So I drilled and tapped a port on the intake, and it started a lot better cold, and just touched the starter hot and it cranked like fuel injection.
 
Still fussin with it. Rechecked for leaks. none found. Pulled it back off and looked around for any cracks or slipped gaskets. Checked the idle diaphragm. No problem found!

Yep, Chris, seems I need to hold the throttles open to get it to fire. Guess I got spoiled on the other one, which I never had to touch the throttles. Cold start was just a 5-10 second wait for the propane to reach the mixer, and it was off. Vacuum signal to the lockoff should not have changed, since Im using the same base plate. And it runs better than it has in years...once it does start!

'Round the shop here, been giving it a shot of starting fluid and it fires right up and keeps running!

Jason W ... Have a thought...I have been doing so much reading about these things lately looking for anything that could have been different between the two mixers! I realized there is one thing I have changed. I have not unplugged the "Balance' port. Everything I have found online says I dont need it. Are they wrong? I was thinking I would take the plug out of it this weekend and see what haps
 
Have you tried moving your vacuum reference to a place on the intake? If you are having to hold the throttle open, it sounds like it is looking for vacuum above the throttle plates.

That or could be purging too much fuel when cranking and opening the plates diffuses the fuel some?

Also, have you checked to see if fuel was flowing between lockoff & reg, and reg & mixer while cranking cold? Could be that the springs are stiffer needing more vacuum to flow?
 
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