I bought a remanufactured Q-Jet for my motorhome when I put the "new" engine in. Let me first say that it runs awesome. Plenty of power, no stumbling, smooth idle. When it's warm anyway. The choke opens too quick and the high-speed idle never kicks in. I've been goofing around with the choke settings trying to get it set right. But that's not my question - I'm still learning my way around the adjustments.
My question has to do with fuel apparently pooling in the area indicated by my crude arrow in the picture.
I've been reading up on float level adjustments and it's not exhibiting any of the symptoms of flooding. I don't think. But I don't know what else would cause fuel in that area. It did fail emissions miserably (running very rich). In trying the "lean drop" tuning method, I could turn both idle air screws all the way in and not get a drop in idle. So maybe the float is too high and weeping into the secondaries? Again, it doesn't seem to be running rich and doesn't flood on decel like it would if it were getting a lot of unmetered fuel.
My question has to do with fuel apparently pooling in the area indicated by my crude arrow in the picture.
I've been reading up on float level adjustments and it's not exhibiting any of the symptoms of flooding. I don't think. But I don't know what else would cause fuel in that area. It did fail emissions miserably (running very rich). In trying the "lean drop" tuning method, I could turn both idle air screws all the way in and not get a drop in idle. So maybe the float is too high and weeping into the secondaries? Again, it doesn't seem to be running rich and doesn't flood on decel like it would if it were getting a lot of unmetered fuel.
The binding was the secondary lock-out cam. The high-speed idle lever was jamming up against it. I don't know what would prevent that from happening in the future, but it's good for now.
I sealed up a huge leak at the exhaust manifold and a couple of others where I spliced some new pipes into the old exhaust system just past the manifolds. WOW what a difference. You can carry on a conversation in the cab now!
Next trip is in October and I *think* I've knocked out all the mechanical stuff (knock on wood). I may get cocky and tear up the carpet between now and then. I want to put a floating vinyl tile floor in. But that's another topic....
I sealed up a huge leak at the exhaust manifold and a couple of others where I spliced some new pipes into the old exhaust system just past the manifolds. WOW what a difference. You can carry on a conversation in the cab now!
Next trip is in October and I *think* I've knocked out all the mechanical stuff (knock on wood). I may get cocky and tear up the carpet between now and then. I want to put a floating vinyl tile floor in. But that's another topic....
ssia2485 wrote:turbojimmy wrote:
Okay - all the cylinders except #5 are 150 PSI. #5 is 140 PSI. I think that's close enough. I guess the blow by is "normal".
Check the PCV valve if it has one. If its plugged it will blow oil out in the areas that you are describing. Compression numbers look OK
Thanks. It does have a PCV. It's off of the "new" engine and is probably 10 years old. I'll replace it.
Okay - all the cylinders except #5 are 150 PSI. #5 is 140 PSI. I think that's close enough. I guess the blow by is "normal".
I finally got it working as it should - sort of. I have the choke adjusted so it snaps shut like it should. I got the vacuum pull off adjusted to crack the choke open like it should. High speed idle kicks up to 1900 per the sticker on the air cleaner. BUT, it does not do all of this on its own. I have to manually manipulate the lever by the choke housing. Something is binding over there. I need to look at it a little closer. And I still need to lean it out to get through inspection.
While letting it idle, I noticed a significant amount of blow by. It's pushing oil out the distributor, oil fill and breather. Not a lot, but when I put my finger over the breather hole it develops some significant crankcase pressure. So I might be done anyway. I'm going to do a compression check once it cools off.
While letting it idle, I noticed a significant amount of blow by. It's pushing oil out the distributor, oil fill and breather. Not a lot, but when I put my finger over the breather hole it develops some significant crankcase pressure. So I might be done anyway. I'm going to do a compression check once it cools off.
Mike Hohnstein wrote:
Go Here
Some times a specialist is required. I'm real familiar with Q-jets and have done many of them, however best 400 bucks I've spent lately was with this place.
Thanks, but it's a fresh rebuilt from a guy with a good reputation. My issues were self inflicted by trying to take a short cut around sealing the choke stove plate.
My brother reminded my that my old GTO had a quadrajet, as well as all of the Pontiacs and Chevys we messed with when we were young. And, one of my dad's Vettes still has the stock quadrajet on it.
I went over to my parents house to rummage through the cabinets in the garage. JACKPOT! I found a stack of about a dozen quadrajet rebuild kits in varying states of completeness - from still sealed to completely picked over. I grabbed a new accelerator pump (Delco instead of whatever the other guy put in) and a gasket. Put it back together and it's running decent.
I must have inadvertently fixed some sort of leak. Previously, I had to back the throttle stop the whole way out in order to get it to idle at 700. Also, with the idle air screws closed completely it still ran fine - no change in RPM. This time it was really lopey when I fired it up. RPM was very low. I cranked the throttle stop in about a turn-and-a-half to get it up to 700 RPM and it's steady there. Seems to run as well or better than it did before.
Now I'm back to where I was a couple of days ago - I need to mess with the high speed idle cam to get it to kick up when it's cold.
I noticed something else about it last night. The secondary metering rod hanger is bent pretty good. I did NOT do that. One rod is hanging lower than the other as a result. I bent it back straight again, but I wonder if maybe one secondary jet wasn't sealing because the rod wasn't down all the way?? Dunno.
sjholt wrote:
If you want to, give me the number of that carb and I'll let you know what jets, primary rods, and secondary rods should be in it.
I might even have them.
Rebuilt carbs are usually all messed up. I only worked on the original carbs on the car when I was in business. I have an old Delco parts book on the Qjets. When setup right- they are good for fuel mileage and performance. I had one on my old 86 32' gasser that I use to get 9.5 MPG at 65 mph.
PM me.
Thanks! I'll PM you. In taking it apart, I noticed that the secondary metering rod hanger was all bent up. Rods are "DH", hanger is a 33797 "J". Not sure if all that's correct for my application.
eHoefler wrote:
Actually, that area is part of the fuel bowl of the carburetor. The rods going down in the fuel are your secondary fuel metering rods. When the secondary throttle plates open, air is drawn in causing the butterfly to open and raise the metering rods allowing fuel to flow into the secondary bores. As far as the high idle, there are two different ways to adjust it, depending on the series of the carburetor. Most common, there is a high idle adjusting screw on the cam, the other way requires to bend the high idle cam rod.
Thanks. Mine has an adjustment on the cam. I haven't messed with it since it's not running at the moment. Once I get it put back together I'll see what I can do to get it to factory specs. The emissions sticker says high idle should be 1900 RPM, normal idle 700.
Richert wrote:
Didn't read any suggestions on the forum, BUT, here is what I did with my GM truck with a quadrajet carb, I went to a speed shop and bought a Holley replacement for the quadrajet, solved all my headaches for over 15 years. Just a suggestion.
They work great when set up properly. I've gone back and forth between Hollers and QJets on my old Pontiacs. For this motor home I wanted to get the stock carb for emissions testing. Hasn't passed yet tho....
