Rochester Qjet issues

[FORD*DIEHARD]

Alright, I have other threads from when i installed this but i think this is a different issue.

Veh info- '74, 302 automatic.

Rochester Qjet purchased and built by (Bruce)- received it with a broken plastic part on the choke part (he said he would not effect performance) but he would send me a new one, never did, tried to get a hold of him, no response. I know he is a one man shop and busy but no response. Installed the Rochester Qjet that supposed to be pretty much plug and play, seemed like the carb was not performing like it should. With no response from (Bruce) I ended up taking it to (Sean at SMI), the first time I took it to (Sean) he said the choke was not working so he replaced that and said the carb I was sold was a '75 and he wouldn't use anything older than a '76. He said it needed to be adjusted but didnt have the adjustment for it, which I showed him my receipt from (Bruce) that showed I paid extra for the adjustment but he said he couldn't find it. I ended up taking it back a couple more times to (Sean) , still not happy how it ran (I dont think I had too high of an expectation from everything I have read and discussions I have had with people who had this set up (Bruce and Sean) were highly recommended as the go to (not saying anything bad about either one, maybe I am the (01) in 1,000 that got a bad carb or just plain bad luck. A couple of weeks ago I went to go talk to (Sean) and he mentioned he is closing shop, I have not followed up to see if he has yet or not, so I found another shop that I took it to . He said he adjusted everything. On the street seems like its running better (haven't really driven it enough). So this past week I took MY GURL out and hit some trails for the first time with this carb. I WAS SO EXCITED, THIS IS WHY I SPENT ALL THIS MONEY ON THIS CARB (my previous carb was the Holley 500 2v, would always stall or bog down really bad on inclines and declines. Thought those were issues of the past until I started climbing, she started doing the same thing with this Rochester Qjet. I dont think I can post video but you can hear it. I talked to another EB guy with the same set up that suggested to zip tie the choke open, but I never got a chance to try that out.

Its frustrating still having this issue with this carb. I didnt cut any corners getting it built and going to "the best in the business." So before I try zip tying the choke open are there any other suggestions/recommendations that you may have had success with?

Everyone says to go fuel injection.

If you need more info to help or if I could send you video to hear it if that helps please let me know. I am going to try and attach video, hopefully it works.

Thank you in advance for your time/help,

Sonny

 

[nvrstuk]

We need more info.

You need to rule things out, like the choke. ZIP TIE it so the choke possibly causing a problem can be ruled out. Help us help you.

It's hard to diagnose with typed back and forth answers, the more info the better.

Keep calling Bruce. Leave multiple msgs. Tell him you want him to fix it, fix it right.

Q- what fuel pressure are you running?

Q- what type of regulator are you running- important

Q- what measurement is the float at? (important)

hard to tell on the video but it seems like the qjet's float level is too high or low (dang hard to tell) and it's exposing the jet or washing over into the venturi hence the stumble at the top of the climb.

 

[Yeller]

30 years ago when I ran them I had to run them backwards on the intake, otherwise I ran out of fuel on longer steep climbs, the float would hold the needle closed. But my memory is bad, last one I ran was in 98 or so, finally did fuel injection for myself (started doing TBI for others about 1989). There are several here with more recent experience than myself, like nvrstk

 

[nvrstuk]

Yeah, a lot of guys ran them backwards!

 

[phred]

Yeah, a lot of guys ran them backwards!

I’m still running mine backwards. It’s been rock steady for the past 10 years.

 

[Soylent]

I would assume you have to switch to a lokar throttle cable to do that.

 

[nvrstuk]

I built many off-road Qjets.

I had to quit running one because I wasn't interested in the chasing the ability to make it happen. I had two avenues I was looking at.

1- enlarging the bowls to hold enough volume to allow me to have the reserve for a thirsty 418 then my 464cu strokers at WOT for extended periods of time on inclines

or

2- go with a an electric switchable regulator that I could quickly switch on at my shifter or a paddle type shifter when I needed to go from 3psi at crawl mode to 8psi to WOT mode. Otherwise I might still be running them.


Amazing how well they do.

 

[nvrstuk]

I would assume you have to switch to a lokar throttle cable to do that.

I set them up with a BC Broncos cable. I have no idea if it was a repackaged Lokar or not. Back when Chuck was running things in the mid 90's.

 

[phred]

Yes lokar cables for carb and kickdown for c4. It does increase pedal pressure a fraction because of the extra length of the cable and the loop around the carb but I’ve never had an issue with it.

 

[73azbronco]

What choke is on it, electrical? Temp? Mine has electrical, flawless.

sounds like, based on video, and the insane angle, your fuel delivery is suspect. I'd make sure you have a full tank, verify fuel pressure to carb at that angle. Lift the front using winch on a tree and see what fuel pressure you get, or try the hill again with fuel pressure gauge visible from cab.. I run a fancy expensive aeromotive bypass FPR to get 4.5 psi to carb, using an EFI in tank fuel pump capable of 75psi output. All the extra blows back into the tank. I know I have enough capability. But, I have never gone up a hill that steep in my current rig.

 

[Ol'Blue]

Hey Sonny, Sorry to hear your having issues. Bruce has built me two carbs and never had issues on inclines like that under normal temps and good fuel pressure. Only when under hood temps are getting to the point of fuel in bowl boiling and losing fuel pressure. How are your under-hood temps? Not necessarily coolant temps but under hood temps.

When mine gets hot, I lose all fuel pressure and I can hear the fuel percolating in the bowl.

If you have a fuel pressure gauge, is there a way to get a video of it on the same hill?

As others have said, keep trying Bruce.

 

[bronco italiano]

I would call Bruce, take your bronco to him and have him dial in your distributor/qjet. He is old/grumpy, but stellar rep from many.

 

[FORD*DIEHARD]

Sorry everyone, I thought I clicked on the notify me for replies, I just saw all these messages.

**First, I just want to make sure it's clear that I AM NOT SAYING ANYTHING BAD ABOUT BRUCE OR SEAN at SMI. I know/understand all parts are different and most are used/rebuilt and things happen. Just frustrating!

As I have said, I am still learning so sorry if these are dumb/simple questions;

Nvrstuk- how would I know what type of regulator and what measurement the float is at?

When I took it to Sean at SMI he said the fuel pressure was were these carbs like it (I believe it was between 4-6).

Ol'Blue- regarding Underwood temps, I have the fiberglass cowl hood with vent holes so I think or should I say thought that would help keep under the hood "cooler" but could be wrong. As outside temps rise sometimes I do notice the engine sounds different. How would or what would could I do to help get under the hood temps lower?

73azbronco- I attached a photo of the choke , not sure how to tell if its temp or electrical) I am assuming electrical.

Fuel tank was full. Not sure what fuel pressure was at this incline. It would also "boggle down" /stalled once on declines , would this be same issue as inclines or separate?

I had the water pump changed a couple of years ago with (I believe it was from Wild horses- the best one available) .

I attached photos of the engine compartment to help show my set up (** I have been on this forum long enough, I know the 1st thing you want to say is YOUR ENGINE IS DIRTY, CLEAN IT- lol! Just got back from taking MY GURL out, I'm going to be cleaning it, I've been working) so with that out of the way..... I have the 7 blade fan, external trans cooler. I just replaced both fuel filters.

I really appreciate everyone's replys and knowledge!

If you need additional info/photos pleaseet me know what would help.

Thank you in advance for your time/help,

Sonny

 

[nvrstuk]

You're good!

I would much rather see a dirty engine that a clean one. Means you don't own a museum piece!

Float levels are checked by pulling the top off the carb, inverting it and measuring the distance between the float and the the alum

 

[Yeller]

If that is dirty don't go look at anything I own

the bogging down going downhill is as important as it is stumbling going uphill. However, if on an extreme incline, it is somewhat more normal, the float doesn't close the needle until it is spilling over, and why many of us do/have run them backwards, it is easier to deal with under power than when not. But it can be dialed in to be better.

 

[nvrstuk]

I didn't complete my last response, sorry.

Like Steve said. I'm guessing that since it's doing it uphill and downhill that the float is set too high or the pressure is too high on the regulator.

What type of regulator again??? I don't remember seeing that. You NEED a regulator to stop the gas flow when the needle and seat aren't level or close to level like a regular carb/truck application.

The hill in the video is steep, but it's a soft surface and your Qjet is still sputtering. On steep surface that's loose like that it would need to be much steeper (as in no way could you climb it at that speed) to cause the Qjet to stumble when dialed in properly. Rocks that are the ultimate traction would allow you to climb at a crawl (and not stumble) and it would be 20deg steeper.

Bruce needs to answer his phone.

 

[FORD*DIEHARD]

I'm assuming your asking about a "fuel regulator ", not sure. Where would that be located so I can look for it?

I also just had the Lokar kickdown cable installed . If I ran the Rochester qjet backwards that would not work now right?

 

[nvrstuk]

Regulator would be found in line btw the carb and fuel pump.

Follow the fuel line.

 

[73azbronco]

thats an electric choke, make sure it's hot to touch when engine on or even just in run with engine not on. You adjust choke by rotating, and i personally think you need the black cover to keep the temp hi. Essentially it heats up, closes choke then as engine warms it opens back up do to ambient heat around that device.


It would also "boggle down" /stalled once on declines , would this be same issue as inclines or separate?


Yes, you can bog down going down when pickup loses fuel and you lose pressure. It can also be flooding going down do to to much pressure, hence, my solution, hi pressure pump with return bypass regulator. Lots of capability, small chance of percolating fuel as it cycles back to tank.

 

[FORD*DIEHARD]

I dont think I am currently running any type of regulator (unless its built into the carb) I also have the electric fuel tank selector switch from WH. I attached some photos from the mechanical fuel pump to carb.

Ok, so researching what has been recommended (high pressure pump with return bypass) I have some additional questions;

1- there are several different ones out there, which one is recommended (not cheap and not the most expensive but something that will last?

2- if I have dual tanks is there one available for a dual tank? My rear tank is an aftermarket (23 gallon and I believe it already has a return port available which I do not believe the stock auxiliary tank has). Since I have a 23 gallon tear tank I dont think in would ever use that much fuel on a single day trail or within a couple days, could I just get a unit with a single return and just use my main tank when offroading ?

3- regarding (Ol'Blues's ) question with under the hood temps, can anyone help with that? Is it necessary to find/get this temperature? How do you take underhhod temps to see what it is? How do you help regulate/control this? Again I have the fiberglass cowl hood with holes already, I thought that was the purpose of putting these vents in (photos attached)