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Carb Issues?

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Frank C.

Frank C.

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I am having an issue that I think is carb related on my BJ8. I rebuilt the two carbs last winter and went through all the re-assembly and tuning guides. In the end it started and seemed to run great but I noticed that after I drove for a few miles the engine starts to miss and the idle speed drops to the point that it stalls out. I think the reason for the delay in the reaction is the it takes some time for the carbs themselves heat up.

I thought it was my poor tuning skills so I took it to a local LBC shop with the same results. I even rebuilt the float valves again.

Is there something inside the carbs that could cause this problem. Any help would be appreciated.

Thanks as always,
Frank
 
Hi Frank what type ignition system do you have?????
 
Pertronix points and high voltage coil (about 5 years old). After I experienced the problem I replaced the distributor cover, wire and plugs so I thought I could rule these out.
 
Is air venting into your tank to replace the fuel you've burned? Sounds like it could be starvation. Is there a rush of air when you take the cap off? How's your fuel pump?
I very much doubt that carbs heating up is the issue.
Other causes? I've experienced rotor arms that become conductive when hot, and coils that deteriorate with heat, too.
 
I'll check on the air issue ... hadn't thought abut that. Fuel pump seems good, I can't make it starve out. As for the coil, It appears to have good strong spark even when it's in the low idle mode. When it is dying out at idle I can keep it running by manually revving it up.

Thanks for your help.
 
I recently had the exact same problem.

I opened up one of the float bowls and one was dry. The other two were fine. I cleaned up the float pin a bit more and all is well now.

Grover
 
Hi Frank,
Tuning HD8s can be tough. I would suggest you post the procedure you used to tune them. It could be in the method you used. I had problems with mine last year and it sounds like your problem is the same I had.
Bobby R
 
I looked at a number of procedures including videos (John Twist) and basically followed the procedure that I downloaded from Steve Byers. As I mentioned, I also had a pro do it and the results were the same so I don't think it is just the procedure. Things keep coming back to the floats even though I've replaced them twice so I'm going to pull the bowls again and see what I find.

Thanks for all the advice and I'll leep everyone posted on what I find.

Frank
 
Frank C. said:
I looked at a number of procedures including videos (John Twist) and basically followed the procedure that I downloaded from Steve Byers. As I mentioned, I also had a pro do it and the results were the same so I don't think it is just the procedure. Things keep coming back to the floats even though I've replaced them twice so I'm going to pull the bowls again and see what I find.

Thanks for all the advice and I'll leep everyone posted on what I find.

Frank
Click to expand...
One of the most overlooked thing is the fuel line for carb and fuel pump problems. It can cause different symptons/problems. Disconnect the line at the pump and carbs and blow out with an airhose. Also, gently blow it out while it's still hooked up to the tank, but be carefull beause you don't want gas coming out of the fuel cap!! The sump can have dirt in it. After "gently" blowing the line from the pump to the tank, disconnect the line and use more air-pressure to thoroughly clean out the line.
 
Frabk C:

Did you also replace the rotor , and does the rotor have a rivet in it??????
 
Hi Keoke,
Hope you're doing well. I was wondering where you are getting the ignition rotor without the rivot and what the part# is. This problem with Franks car really reminds me of the low idle screw and the choke idle screw are out of sync with each other. Oh well, as always, thanks for your help.
Bobby R
 
Hi guys,

Just a quick update ... no progress! To answer some of the questions above:
1. I've already experienced the bad rotor issue and have replaced my last year with the Moss Premium Ignition rotor (pn 872-785) and haven't had an issue since.
2. I and a "real" British car mechanic have tuned and re-tuned the low and high idle with the same results.

The fuel pump is always an issue and I think I'll have to get the pressure checked to see if there is any issue. It is very frustrating because I just pulled to float chambers and checked/reset the valves, then started and ran the motor for a good 20 minutes, then I went for a drive and really pushed it. It ran great no matter what I tried, then after I had run about 15 miles and just pulled back into my neighborhood, I started choking out again and stalled when I came to a stop.

I just pulled the low idle screws out again to see if there are any obvious issues ...

To be continued ...
Frank
 
Frank,

If you don't do anything after it stalls but let it cool, does it run fine again or does it try to stall again right away?
 
Are the jet assemblies returning all the way when you go off choke? If one is hanging up and you're tuning it that way, when the carb gets really warm, it could return fully and you would be too lean. Next time this happens, pull on the choke and see if it makes a difference.

John Turneys question is a good one.

Marv J
 
When your car misfires are you still able to drive it at speed? or is the misfiring so bad that the car will hardly move? First change the coil since its easiest, and it could be breaking down when it gets warm under the hood ( don't care how old it is or how you've checked it) , next recheck your valve lash , make sure you don't have a tight valve hanging open when the engine warms up. Give them carbs a rest !
 
John,
Yes, the car runs fine after it cools off.

Marv,
The jets appear to be well centered and operating smoothly but I haven't tried the choke trick. I'll see what happens.

Brinkerhoff,
I can still keep moving (with work) by keeping the rpm's up but I haven't pushed it too long this way. I have been keeping the trips close to home and head back as soon as I have the problem. I think I still have my old coil so maybe I'll give it a shot. As for the valves I had them adjusted and the issues stayed the same.

Thanks as always and keep your fingers crossed!

Frank
 
Ok, it's not the coil ... changed it with the same results.

Pulling the choke out didn't seem to help either ... anyone want to buy and newly repainted BJ8?

I'm making plans to have the fuel pump pressure tested now ...

Frank
 
howdy all,
recently posted about my HD8 rebuild-problem with driveability
related to loose fitting [worn]taper pins,once replaced all linkage problems corrected
with respect 59er
 
I've encountered a bad battery cutoff switch. When it got hot it would lose the connection. The car would run for a couple of miles then start to miss then quit till it cooled down.

It affected the wire that grounds the coil. Check the wiring diagram and disconnect the wire from the cutoff to either the coil or the distributor.
 
In addition to my Healey problems, I took a hit of lightning last night and lost cable, TV and phone until at least Wednesday. Not complaining ... many have it so much worse! I'll try to connect remotely occasionally to check in and give status reports.

On the car ... I don't have the kill wire connected to the ignition system so I don't thing that the cutoff switch is to blame but it was in interesting system.

I am taking the car to a pro next week to get his input ... I'm too close to the problem now ..

Frank
 
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