Still Having problems with the PROBLEM CHILD-Lean/miss/stumble/backfire!!!!
05-20-2003, 04:22 PM
#41
Registered
Join Date: Nov 2001
Location: Pennsylvania
Posts: 3,385
Likes: 0
Received 0 Likes
on
0 Posts
Bad Habit, I reread the description of your problem from start to finish. Here are some idle rantings that hopefully will help the troubleshooting.
Is it correct that you can get past the mid-range miss/bog and above 4500rpm the boat runs fine, just lean. Or, is 4500 WOT? It feels like you may have two problems... fuel delivery/ carburation and the intake leak. Sounds like you are getting a grip on the intake leak, but the fuel/carburation is still elusive. I think I read you changed to high flow needle and seats? If so, did you adjust the float accordingly. Not sure about edelbrock carbs, but on qjets this is important. What it seems like is the power piston is not opening when vacuum drops, thus leaning things out at cruise speed. Are the plugs a decent color after idling, or is it lean there as well? Sorry if you have already answered that. If it is lean even at idle and you have reasonable fuel pressure, you must have a carb problem or massive vacuum leak. Your vacuum was on the low end, but did not sound outrageous (like a tulipped valve). Are you sure the power piston is moving freely and that the spring is in place under it? I think you can inspect this on the edelbrock while the engine is running.
Multiple problems are a *****! Sorry for your trouble,
BT
Is it correct that you can get past the mid-range miss/bog and above 4500rpm the boat runs fine, just lean. Or, is 4500 WOT? It feels like you may have two problems... fuel delivery/ carburation and the intake leak. Sounds like you are getting a grip on the intake leak, but the fuel/carburation is still elusive. I think I read you changed to high flow needle and seats? If so, did you adjust the float accordingly. Not sure about edelbrock carbs, but on qjets this is important. What it seems like is the power piston is not opening when vacuum drops, thus leaning things out at cruise speed. Are the plugs a decent color after idling, or is it lean there as well? Sorry if you have already answered that. If it is lean even at idle and you have reasonable fuel pressure, you must have a carb problem or massive vacuum leak. Your vacuum was on the low end, but did not sound outrageous (like a tulipped valve). Are you sure the power piston is moving freely and that the spring is in place under it? I think you can inspect this on the edelbrock while the engine is running.
Multiple problems are a *****! Sorry for your trouble,
BT
05-20-2003, 05:45 PM
#42
Registered
Thread Starter
Join Date: Jul 2001
Location: SW Ohio
Posts: 770
Likes: 0
Received 0 Likes
on
0 Posts
The bog is ever present at least under 4500....The miss happens at cruise between 3000 and 4200 or so. I can over come by staying below or above this range. I have not re-set the float for the hi-flow needle and seat kit. But I will call edelbrock and get their specs...As far as the power piston I think that would cross over to the metering rod springs. I think I have read that you can check the operation of the rods. I have not checked this but did change the springs to the ones that operate the easiest/quickest....What should I be looking for on the rods/power piston and their operation? The plugs seem to actually be VERY rich running ON THE HOSE... LOTS of carbon and strong gas smell. BUT this was before I got the intake situation corrected/plugged. I havent' checked them at idle since I sealed the gap on the intake. SOOOO If I'm not lean at idle then what does that lend itself too? Tommorow will be (weather permitting) install of the new pump and fuel lines....I will re-set the float and get ready for anouther 2hour trip back and forth to the lake to check this thing out 
I can't thank you guys enough for all your help so far. I won't go on and on about how little I have left for all this (money
,patience and time.) Suffice to say it's people like you guys that make this board and sport special.....I will update a.s.a.p. and KEEP THE IDEAS COMING!!!!!
BH
I can't thank you guys enough for all your help so far. I won't go on and on about how little I have left for all this (money ,patience and time.) Suffice to say it's people like you guys that make this board and sport special.....I will update a.s.a.p. and KEEP THE IDEAS COMING!!!!!BH
05-20-2003, 06:50 PM
#43
Registered
Join Date: Nov 2001
Location: Pennsylvania
Posts: 3,385
Likes: 0
Received 0 Likes
on
0 Posts
Do yourself a favor and check the anti-syphon valve operation and the screen behind it when you put the pump in. If you don't already know, this is an in-line checkvalve that is typically located at the outlet of the fuel tank. It often looks just like a brass 90* elbow. Causes boaters lots of trouble and is easy to fix.
I have not worked on edelbrocks, but am fair on a qjet. Qjets have the same power valve. Reading Dennis Moores section on edelbrock it say "you can remove the cover and watch the operation of the power piston as you rev the engine." If the power valve is not moving, it would lean your engine out at cruising range. This power piston is what moves the metering rods up under low vacuum (throttle open). That is, the spring moves the piston up when the vacuum drops. A lighter spring will make the cruise a/f ratio leaner... at least on a qjet and I think on yours as well. A heavier spring will make the cruise a/f ratio richer.
The gas smell at idle is probably your idle mix circuit is tuned too rich, but I wouldn't worry about that for the moment. Rich is good. I am really leaning toward the anti syphon valve or a clogged screen.
I was going to change my needle and seats last week, even bought them (qjet), but chickened out. This is a fairly sensitive change and needs to be handled properly from the float setting standpoint and fuel pressure standpoint. Doing this stuff wrong would probably result again in a rich or flooding condition, so that is not your problem.
Anti-syphon valve and screen or any other filter you have not yet replaced.
BT
I have not worked on edelbrocks, but am fair on a qjet. Qjets have the same power valve. Reading Dennis Moores section on edelbrock it say "you can remove the cover and watch the operation of the power piston as you rev the engine." If the power valve is not moving, it would lean your engine out at cruising range. This power piston is what moves the metering rods up under low vacuum (throttle open). That is, the spring moves the piston up when the vacuum drops. A lighter spring will make the cruise a/f ratio leaner... at least on a qjet and I think on yours as well. A heavier spring will make the cruise a/f ratio richer.
The gas smell at idle is probably your idle mix circuit is tuned too rich, but I wouldn't worry about that for the moment. Rich is good. I am really leaning toward the anti syphon valve or a clogged screen.
I was going to change my needle and seats last week, even bought them (qjet), but chickened out. This is a fairly sensitive change and needs to be handled properly from the float setting standpoint and fuel pressure standpoint. Doing this stuff wrong would probably result again in a rich or flooding condition, so that is not your problem.
Anti-syphon valve and screen or any other filter you have not yet replaced.
BT
05-20-2003, 07:19 PM
#44
And please, dont assume that the bead of caulking you ran has fixed the intake leak problem. You could still be leaking between cylinders or to the lifter valley. Pull it off and do it right. Im just learning quadrajets and cant wait to hear the end of this story.
05-20-2003, 10:34 PM
#46
Registered
Join Date: Nov 2000
Location: Crystal River, FL
Posts: 222
Likes: 0
Received 0 Likes
on
0 Posts
Bad,
Sorry to state the obviouse, however I have never heard of so many problems sealing an intake manifold. You took the right path by using red rtv sealant, and a thin bead should have eliminated any casting imperfections period. You also may need to check your bolt length's, even if you properly torque the intake if the bolts are bottoming out you will never seal the leak. This is also possible with the carb bolts.
Typically there is never any one fix for dialing in a motor other than a good deal of patience. Don't second guess your effort, and don't jump around the motor. No short cuts.
Start at the top and check each and everything you have assembled. You understand white plugs mean lean, correct the intake leak (by the way starting fluid usually raises the idle) and then you may need to re-jet the carb.
As already mentioned I don't agree with only 4 p.s.i. for fuel pressure I want 7-8 minimum, check pump, supply line and clamps, and tank vent to be sure there is no restriction.
You will beat this problem!
Sorry to state the obviouse, however I have never heard of so many problems sealing an intake manifold. You took the right path by using red rtv sealant, and a thin bead should have eliminated any casting imperfections period. You also may need to check your bolt length's, even if you properly torque the intake if the bolts are bottoming out you will never seal the leak. This is also possible with the carb bolts.
Typically there is never any one fix for dialing in a motor other than a good deal of patience. Don't second guess your effort, and don't jump around the motor. No short cuts.
Start at the top and check each and everything you have assembled. You understand white plugs mean lean, correct the intake leak (by the way starting fluid usually raises the idle) and then you may need to re-jet the carb.
As already mentioned I don't agree with only 4 p.s.i. for fuel pressure I want 7-8 minimum, check pump, supply line and clamps, and tank vent to be sure there is no restriction.
You will beat this problem!
05-21-2003, 01:48 AM
#47
Guest
Posts: n/a
When you say the plugs are white, do you mean the electrode and ground strap are white or do you mean there is no color on the white porcelain? These new reformulated fuels just dont put color on the plugs.
Sorry if this was already covered, I didnt read the whole thread.
Sorry if this was already covered, I didnt read the whole thread.
05-21-2003, 08:14 PM
#48
Registered
Join Date: Aug 2001
Location: Gainesville Fl.
Posts: 573
Likes: 0
Received 0 Likes
on
0 Posts
Float setting 1 9/32 with 5 psi. 1 5/16 with 8 psi fuel perssure .The springs you should be using are Orange-red will not raise piston uitil vacuum drops to 5". I am running Orange-red spring .065-.047 rods for now,.113 jets in both front and rear.I'am useing the Edelbrock # 1466 needle and seats at .110 and useing the leanest pump shot and have no problems.My plugs to some would seem like they look white but with a tad of tan on the porcelain but my heat line is on the curve of the ground strap. ps I still don't think you have a vacuum leak,but if I thought the vacuum was realy to low and I was going to check for a leak on the top side of the gasket only ,just run a bead of water buy the ports and if it is on the top side it will be sucked in with no guess work 
ps I still don't think you have a vacuum leak,but if I thought the vacuum was realy to low and I was going to check for a leak on the top side of the gasket only ,just run a bead of water buy the ports and if it is on the top side it will be sucked in with no guess work
Last edited by FloridianSon; 05-22-2003 at 01:52 AM.
05-22-2003, 04:27 AM
#49
Registered
Thread Starter
Join Date: Jul 2001
Location: SW Ohio
Posts: 770
Likes: 0
Received 0 Likes
on
0 Posts
Got off the phone with Edelbrock Tech. THEY say float level (inverted)should be @ 7/16" and that float drop should be 1-1/4". Also stated that Min Fuel Pressure should be 5psi with 6-1/2 the max....Ive gotten 2 answers from their tech on fuel pressure though. First time it was 2lbs min @idle and 4lbs@ W.O.T. Anyways the fuel pump should be on today. As far as springs Im currently running the plain springs which is the richest quickest setting. As far as the plugs the porcellen after a run is WHITE not just some of it ALL of it. The ground strap is clean as a whistle with a spot about 1/16" off the base having a slight line. Funny thing though at idle on the hose the plugs are RICH big time. It's at speed they are lean....As far as dialing in the motor I dont' look at this as what im doing...Isn't that what you do after major changes or when setting up a new motor...This thing ran GREAT for the first 40 hours!!!!!! THEN with no changes and with no warining I got the bog under hard acceleration and miss at cruise Along with the "GHOST PLUGS!) Anyways hopefully I can get everyone here some updates on my little soap opera a.s.a.p.
Thanks again everybody you are my life-support right now...Because I think unless I hit the jackpot or get this fu**ing problem child fixed SOON(Ive been on this problem for 10 months now) My wife (family for that matter) will want a divorce
BH
Thanks again everybody you are my life-support right now...Because I think unless I hit the jackpot or get this fu**ing problem child fixed SOON(Ive been on this problem for 10 months now) My wife (family for that matter) will want a divorce
BH
05-22-2003, 08:59 PM
#50
Guest
Posts: n/a
Could you post a pic of your plugs? It sounds like your running fuel thats just not leaving color on your plugs. You need to get a spark plug magnifying glass thats lighted. If your really lean, you will get a white buildup on the strap.
Heres a link. Theres a good section on reading the color ring at the base of the porcelain.
http://www.strappe.com/plugs.html
I went through this last year when I put a new carb on. I kept going fatter until it started losing perfromance and still no visible color. The new fuels, especially the reformulated fuels we get in major urban centers do not leave color for many hours.
Maybe your chasing a problem that has nothing to do with the color of your plugs?
Heres a link. Theres a good section on reading the color ring at the base of the porcelain.
http://www.strappe.com/plugs.html
I went through this last year when I put a new carb on. I kept going fatter until it started losing perfromance and still no visible color. The new fuels, especially the reformulated fuels we get in major urban centers do not leave color for many hours.
Maybe your chasing a problem that has nothing to do with the color of your plugs?
Last edited by Mr. Demeanor; 05-22-2003 at 09:18 PM.
