Pirate 4x4 banner

1 - 18 of 18 Posts

·
Registered
Joined
·
275 Posts
Discussion Starter #1
Here's what I have. A 72 Ford Bronco with a 302 with a OHG450 mixer on top of a 4 barrel throttle plate. This is being feed by a Model E regulator (just rebuilt) through an electric lock off. I can't get it to even ack like it wants to fire. I have spark at the plugs and propane to the mixer, but still no fire? Tank is full of propane and am using the manifold for my vacuum source. Still nothing?? Any suggestions or ideas??:confused:
 

·
Premium Member
Joined
·
12,578 Posts
An engine only needs 3 things to run:

1) Ignition
2) Air
3) Fuel

Assuming you're not working in a vacuum, I assume you have #2. (Although it's possible that your baseplate could be stuck open or closed, which would either give you too much ro too little air.) You say you're sure propane is getting to the mixer, so that rules out #3. You're getting spark you say, so your timming could be off. If you're sure you timming is right, that rules out #1. Therefore, your engine should start and your problem is solved! Congratulations!

That or you're wrong on one of your assumptions, which is what I'm betting on. :) So give us some more info. How are you sure propane is getting to the mixer? How are you sure you're getting spark?

An OHG has 3 poles that go down into the base of the carb when you take the top apart. Take it apart and make sure that they move freely. DO NOT lube them. It also has a large square broken o-ring that goes all the way around a bore of the big giant plunger that moves up and down on those 3 pegs. Make sure that is there. Also make sure that the diaphragm has no holes in it. Beyond that, without more info, I don't know what to tell you.

J. J.

PS: You have the EXACT SAME LPG setup that I run. The only time this ever happened to me those 3 poles were dirty and getting stuck in place not allowing propane to get through the mixer. But that would mean you were wrong on assumption #3, and that wouldn't be possible, would it! :)
 

·
Registered
Joined
·
275 Posts
Discussion Starter #4
I and HOS both ckecked the distrubitor last weekend and it's pointing at #1 at TDC. The mixer is rebuilt from Propaneguy.com.

Baseplate isn't stuck and functions without sticking. I'm sure propane is getting to the mixer because I've removed the vapor hose at the mixer and by pushing the primer button on the front of the vaporizer I get propane coming out at the mixer end. I don't know that it's getting through the mixer to the engine, but I'll pull the top off and check the hole you discussed. I checked spark at the coil got a good spark. I then pulled a spark plug and checked spark there too and saw nice spark.
 

·
Premium Member
Joined
·
12,578 Posts
Your fuel test to the mixer means nothing and is not proof that there is fuel getting to it. All you prooved is that if you push the little button on the front of the vaporizer fuel comes out of it. All that means is that your vaporizer is working.

And I like Propaneguy and all and I still buy all my stuff from him when I need it, but when I got my "rebuilt" OHG from him it came "rebuilt" missing that big o-ring that goes around that plunger and with the wrong spring in the top. So just because he rebuilt it don't mean it's perfect.

Try this, it should be fairly simple. As you spin the engine with the starter does the big aluminum plunger in the center of the carb jiggle up and down?

Here's a link with a cutaway of your mixer. You can see the o-ring I am tlaking about and the little studs, too: http://franzh.home.texas.net/ohg/

J. J.
 

·
Premium Member
Joined
·
12,578 Posts
You still haven't convinced me about timming either. So you're fairly certain the dist is installed correctly, but how about the wires going to the correct cylinders? Do ANY cylinders fire off at all? Do you get any backfires?

Also, smell close to where the air goes into the mixer as you turn it over. Can you smell propane?

J. J.
 

·
Registered
Joined
·
46 Posts
wrong spring?

ha ha thought i was the only person that had gotten one of those without the o ring in it! so patooyee ive always thought my spring was weak its always ckacking @ me where would i find the right one? i tried shimming it but nothing ever helped it was / is still a week spring. sorry so the hijak. o wasted a cam in my bbc trying to break it in with my new super bling 450x seystem. all my buddies that run a 425 gott a big laugh outta me & my super bling 450x. ne help is much appreciated thanks!
Jerry K
 

·
Registered
Joined
·
275 Posts
Discussion Starter #9
O ring is there and installed correctly.

The plunger does move up and down a little when cranking and makes a popping/backfiring noise.

All the wires are to the correct cylinder, but I didn't check each cylinder to make sure it was getting spark just #1.

I'll check the spark thing tomorrow. Along with smelling for propane at the mixer.
 

·
Registered
Joined
·
9,297 Posts
what 4 barrel throttle plate did you use?
did you plug all the holes in it that arent needed?
is the vacuum line to the idle enrichment installed?
when you crank the motor how much vacuum does it pull?
did you try holding the prime button down while cranking? (dont be over the mixer when doing that)

I am guessing you have a huge vacuum leak
 

·
Premium Member
Joined
·
12,578 Posts
ha ha thought i was the only person that had gotten one of those without the o ring in it! so patooyee ive always thought my spring was weak its always ckacking @ me where would i find the right one? i tried shimming it but nothing ever helped it was / is still a week spring. sorry so the hijak. o wasted a cam in my bbc trying to break it in with my new super bling 450x seystem. all my buddies that run a 425 gott a big laugh outta me & my super bling 450x. ne help is much appreciated thanks!
Jerry K
I got the correct spring from Propaneguy. Mine still chatters at me every once in a while at idle. I just give it about 300 rpms and it settles back down.

Jesse, I'm w/MJ. I think you have a huge vacuum leak somewhere. Got a vacuum guage?

J. J.
 

·
Moderator
Joined
·
5,599 Posts
did you try holding the prime button down while cranking? (dont be over the mixer when doing that)
Do that..If you can push the primer adn get fuel your model e is not froze up.
If that will get it to start you are starving for fuel.

Is you 450mixer the style with a big 1in adjustable screw at the front for fuel adjustment? Mine has it, most are only factory set.

You also have an idle adjustment at the back.
 

·
Registered
Joined
·
9,297 Posts
You also have an idle adjustment at the back.
and a vacuum operated idle enrichment circuit....

there are a ton of areas that can cause a vacuum leak

post some pics and more detail on the 4 barrel throttle plate.
many will require a spacer plate under them to cover some vacuum leaks
many require you to plug a huge hole in the center
without that basic info it isnt easy to help online
 

·
Registered
Joined
·
275 Posts
Discussion Starter #14
I tried to get it to kick over with starter fluid and nothing. So I'm thinking my propane problem is actually not it and it's some where else. I don't have a vacuum gauge, but I'll check that too.
 

·
Premium Member
Joined
·
12,578 Posts
HOw did you spray the starter fluid in? With an OHG you would actually have to hold the air piston open with one hand and spray with the other to get it into the engine.

J. J.
 

·
Registered
Joined
·
275 Posts
Discussion Starter #17
Turns out I didn't have the distibutor installed correctly. Once I fixed that it fired right up on propane, but it's got a knock somewhere. So now onto the next problem, find what's knocking, cause, and fix. Thanks
 
1 - 18 of 18 Posts
Top