dellorto & Holley fuel pres. reg.
 

I'm having problems with my '83 rex. I have a street ported 12a, with a Dell carb, Carter pump, and Holley fuel pressure regulator. The regulator is rated for 4.5-9 psi. I have the adjusting screw on the regulator all the way screwed in, and my fuel pressure gauge is reading 6 psi with the key in the start position, 4.5 psi while the engine is cranking. Anyway, the engine keeps flooding out BAD! I've pulled the spark plugs out, and I do have spark on both leading plugs, however I've noticed the engine is flooded so bad that there's a puddle of gas in the spark plug sockets, and this happens after just 30 seconds of cranking. I'm thinking this may be because the idle mixture screws are too far open. Approximately how far should I open up these screws? Any other ideas on what might be causing this problem? One other thing, I've noticed the engine will usually start after it's sat all night long, and run for 5 to 10 seconds. But never again for the rest of the day.

Not 100% sure but I think the preasure is way too high? I used to run a del. and I think I was running around 3.5-4 psi??? anyone else have opinions???

I know RB recomends 4.5, but for all I know, my gauge may be way off. I here a lot of people talking about there fuel pressure gauge being way off.

The Malloy 4309 goes 3-12 psi and is $72. I have one that I am sending back. If you want it instead of me shipping it back, pm me and we'll work something out.

Fuel pressure should be around 2.5 to 3 psi. try it and you will be happy

Allright, I'll try the lower fuel pressure when my engine isn't flooded, thanks.

According to my Dellorto / Webber Book, all weber / dellorto side draft need a fuel pressure between 1.5 to 2.5 psi....


I have mine at 2.5 and worked fine.....

It's strange that RB would recommend such a high amount of pressure. Nonetheless the general. consensus seems to be lower the pressure

whooooo-weeeee! (said the diabolical one - devilishly rubbing his hands together :D)

man, i've been there ... with the same dellorto problem. just a thought here, but you may end up having to change the pressure gauge to the 1-4 psi Holley unit (Summit's catalog only lists the 4.5-9 psi) the P/N is HLY-12-804 ... i just got it a few weeks ago, and it's like i'm driving a different car!

anyway, play with what you've got, and exhaust all efforts to make it work before you buy another regulator, though ... what didn't work for mine, may work for you.

anyway ... the whole point of this post was to refer you to a thread i did a few months back ... some very good info, and rxcetera solved my problems, so it might be worth a look. i just tried finding it so that i could include the link, but it's like it just up and disappeared :(

try searching though, maybe you'll have better luck than me.

I'll take a look at your thread if I can find it. Fortunately, I have a purolator regulator that I just hooked up that offers me lower pressure. Right now my gauge is reading 3 psi, still no luck.

Metalliman,

Your fuel pressure is set way too high. The proper setting is the 4.5-9psi Holley reg with the screw almost all of the way *up*.

If you have your screw turned all the way *in*, you are running it at maximum and pouring fuel in. The more you turn the screw "out*, the lower the pressure becomes.

The proper fuel pressure for the RB Dellorto is 4.5 psi.

Don't pay any attention to that guage you have - it is not accurate. The majority of the guages out there are useless for tuning fuel pressure.

The way to set pressure is to turn the screw all the way up. Then turn it in slowly until the carb starts to flood. Then turn it back a bit. Go test drive it. If it starts to stumble if you let it idle for a bit, it's too high. Keep adjusting and test-driving through trial and error until it feels right.

The 4.5-9psi model works great on my car. Get rid of that Purolater; word is it restricts fuel flow.

I'd like nothing more than to go out and test drive it over and over again. I haven't driven it since the day I drove it home from the dealership 6 months ago, and it only had compression in one rotor then. Since then, I've rebuilt it, had it running with the stock fuel pump. I guess I'll just wait until tomorrow morning so the engine isn't flooded.

By the way, SilverRocket, do you have any idea where your idle mixture screws are set. My cousin (wannabe mechanic) starting messing around with them when I wasn't in the garage. I'm wondering if this has anything to do with my flooding.

It's been a while since I set them; I believe they are around 3-4 turns out (can't check.. put my car away in storage last weekend, due to going back to school.)

Here is RXcetera's advice on adjusting them:

I don't think this has anything to do with your flooding problem though. I'm thinking that cranking your fuel pressure down will be the ticket.

Well, like I said, I'm running about 3 psi according to my gauge, and this is using the holley regulator with the screw turned OUT. Thanks for that advice. But, i think the engine is so flooded it will take hours for it to unflood. Any safe way to unflood the engine quicker? I tried unplugging my fuel pump and turning it over for a little while. Didn't help any.

Never done it myself... but it will be all over the forum; try the search button.

I think what you'll probably need to do is pull the spark plugs, wipe them off, disconnect ignition coils, crank the motor and watch gas fly all over the place lol, and re-install plugs.

Search though, again I've never done it.

well, this may soubd really ghetto, but it worked for me more times than i can actually remember.

1 - take your plugs out
2 - disable the fuel pump
3 - crank the engine until mist stops coming out the plug holes - (if no one is there to crank it for you while you watch, then just crank it on and off for a few seconds ... 7-10 maybe)
4 - take the plugs and either burn them with a lighter or if you have a gas stove, then just put them there for a little while (maybe a minute)

MAKE SURE YOU PROTECT YOUR HANDS!!!!

5 - reinstall the plugs
6 - hit the gas a couple times
7 - crank the engine without the fuel pump and see if it tries to start
8 - if it does, then enable the pump and fire it up

hope you get it going ... let us know

actually, wait i just remembered that you're running a Dell'Orto, not a Nikki ... only pump the gas once or twice then, or you might flood it all over again.

sorry :D

FUck same problem I just posted!

I say we all burn those damn Holley FPR!

I have the HLY-12-804 and run a carter 7psi pump with feeding my weber...I guess I'll just turn that freaking screw all the way out too

How do I know I'm not running out of fuel then?...I can't trust my A/f gauge.

Correct the fuel problem first.
To unflood clean spark plugs but reinstall, crank the engine with enough juice to crank it well but don't overheat the starter...make sure you have enough power to crank it. Do not step on the gas unless you hear the engine firing up slightly, once it pops a bit step once on the gas to squirt some but not too much.... Use a starter or battery booster...that's what I do...

I'm starting to think there may be something hanging up on the carb. I've set my purolator regulator down to .5 psi, the fuel pressure gauge reads 1.5 psi. After about 30 seconds worth of cranking, I have a badly flooded engine all over again. Is there anything that may be hanging up that would let the fuel directly into the engine?

just a sugestion, have you check the needles? they might be stuck open dude...

check the float bowls if it's only one that is flooding is your carb...

where exactly are the needles? I'm still learing about carbs. i'm guessing there underneath the float bowl cover.

Two-barrel Weber carbies only have only one float bowl (and one needle valve obviously). Not sure about Dells though.

http://www.gruntled.com/Dellorto/DHLA-DIAGRAM.gif

No. 13 on the diagram.

true I forgot it was a dell. Buy a Compaq carb ;)

seriously still it could just be the needle or a bad float level adjustment..that diagram more or less shows you everything.

15 is the adjustment for the float level.

racing beat dellorto
 

i think racing beat recommends 4.5psi of fuel pressure because if u buy a dellorto from racing beat it is modified. it is different from stock dhla dellortos. Racing Beat modified the Dellorto carburetor in several ways. The obvious modification was the addition of the two fittings to connect the tubes from the metering oil pump. Two other modifications that I am aware of are an altered emulsion tube and accelerator pump gasket. Racing Beat no longer has these replacement parts.

I took the float bowl cover off, the needle seems to move quite freely, no sticking or anything. Anyone know just how high the fuel level should be in the float bowl? I guess I'll try bending that tab in order to lower the fuel level in the float bowl, and see what happens.

I just measured the fuel level in my float bowl. It measures 1 3/8" from the bottom of the bowl. This is just after turning the key to the "run" position for 10 seconds then turning it off. Does this sound right?

I'm not sure if that's right or not, but I know the float levels have to be set precisely. I can't remember offhand what the proper levels are.... they are on that website and it's down right now lol. I made a little tool to set mine, basically a tie wrap with the 2 levels marked on it.

Could it be that your float levels are set incorrectly?

How did you set them, and to what heights?

i started a thread a few months ago when i was having trouble with my Dell'Orto, and rxcetera helped me get though it all ... i just did a search because i was going to post a link to see if any of that info would help metalliman, and now i can't find it!

anyone know what might have happened?

I went to that website, couldn't find anything about proper float levels, maybe you could find it?

As for this missing thread, I too would like to find it, but I have no idea what happens to a lot of posts.

Here ya go...

I don't have much clue as to whether this might help your problem, but it's somewhere to start.

Did you rebuild and clean this carb (as you absolutely should have) before installing it? I'm just wondering if there is a more serious problem here.

Thanks for the specs, I'll have to re-measure the float levels today. As for rebuilding the carb, the kit is in the mail, as is my "Dellorto and Weber" book that I ordered. By the way, where did you get those specs from?

From Mr. RXcetera himself:)

It is really important to make sure the carb is clean and in proper condition, has the proper RB spec jets and chokes (people put all kinds of weird things in there), all adjustments set properly (accel pump travel, float heights, pump jet holes lined up precisely), all parts of mixture adjust screws present and working as they should, etc.

You can't count on any of this stuff without making sure; I'm not sure what you've already done, but I'm thinking you might open it up to discover things are not as they should be, and that rebuild kit and maybe a few more parts will cure your problem. Also, that website is a key resource; it's got all the RB jet sizes and instructions on how to make key adjustments. I know that when working on my Dell, it has been a very useful resource.