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Today's journey great start - home on a flatbed

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I had the same problem once! I re-routed the fuel supply line to keep it in the coolest air possible (around the engine on the right side, ahead of the radiator and up the left, inner fender to the carbs). This helped, but I also scrapped the Purolator (screw-apart, replaceable element type) filter in favor of a generic, under $2, plastic one from the local auto parts store and these steps solved the problem for me!
 
now mine is a generic under $5 from Victoria British - anyway will try without and see what happens
 
Plastic fuel filters from any parts house in your home town.
 
Well, I'm still frustrated. I followed up Steve's advice. took out the filter, rerouted the hose as much as I could - behind the heater and along the fender inner. Added some clear hose just to see. Drove about 20 miles, brought it in, let it idle for about 15-20 minutes and took her out again. Got about 5 miles and it started again. Immediately turned around and headed for home. She quit on me once and I restarted - nursed it into a parking lot, opened the hood and it revved again, pulled it out onto the road and while it didn't quit again, it was not a smooth drive.

Here is what I know.

1. she was idling at about 1100 rpm before I had any issues.
2. Just before I started experiencing the issues again, the idle was 2400 rpm
3. As I was driving home it was idling at about 1600 rpms

4. before the issues started, the air bubbles moving through were an inch long or longer, when the problems started, they were small circular bubbles the diameter of the tube (1/4")

5. The hoses were warm to the touch but not hot.

6. I did find a little crud in the float but not much - when the engine is cooler I will check again.

any thoughts?

thanks all
 
none that I can see. Just looked in the float - only as much gas as the bottom where the line goes to the carb. A little bit of sediment.
 
the uneven idle suggests a vacuum leak. Even if the fuel system was causing the trouble, all the idle would do is go from your baseline of 1100 to stall. The only other thing that comes to mind if somehow the timing is going south. Maybe there is a breaker plate problem.
Good luck to ya, and keep us up to date.
Scott in CA
 
I would hook up a dwell gauge and route it into the cockpit so that you can see it when the car is acting up (also a vacuum gauge if you have one). That way you can start ruling some things out.
BillM
 
This reminds me of a problem I had with a 240z. I believe the fuel filter ruptured and allowed 'crud' into the float bowls (Hitachi SU's) this in turn caused the needle valves to get stuck open - flooding the carbs.... The car ran in a similar fashion to what you are experiencing... The car seemed to have a mind of its own - ran okay for a little while then it would run like crap.
Don't know if this helps...
cd
 
Billm said:
I would hook up a dwell gauge and route it into the cockpit so that you can see it when the car is acting up (also a vacuum gauge if you have one). That way you can start ruling some things out.
BillM
Click to expand...

Bill, dwell is for points though isn't it? by '76 it was an electronic ignition.
 
I think then that we may have another culprit! I don't believe that those were the most reliable ignition systems.
I have gone to the extreme of hooking up a timing light and run it into the cockpit so I could monitor the spark ("yes or no") before.
May be the time to try that.

I have heard stories of mysterious ignition problems (MG) where the hot engine had a pinhole leak that sprayed the (electronic) ignition module (only when the engine was REALLY hot) and was nearly impossible to detect. Next time the engine stops pull over immediately, open the hood and look at the module. If it is wet you may have your answer.

BillM
 
I'll try - though don't forget 1500 carb is not on same side as dizzy ie. there's really nothing convenient to spray
 
It really sounds like a vacuum leak. Drive the car around the block until you recreate the problem, then pull her over and spray your carb and manifold with your favorite choice of vacuum leak detector. (ie. starting fluid, WD40, water etc.)
 
Could also be an intermittently sticking float valve. That could cause the hard starting, back firing and high idle as well.
 
single su right?

got oil in the dashpot? what kind?


I was having some problems with a stumble over 3500 changed from 20-50 to marvel mystery oil and voila! no more stumble

the bubbles you describe does sound like a leak on the suction side of the pump (as mentioned above) wouldn't necessarily leak when not running..
 
Oil is 20W50 - had marvel and didn't rev at all. I think I'm going to try an "all of the above" - check & recheck fuel line all along. re-tighten and check manifold. How do I check vacuum?
 
foolish question..
is the gas tank vented?


mark
 
SilentUnicorn said:
foolish question..
is the gas tank vented?


mark
Click to expand...

not foolish at all - yes, there is a gap actually as it is a Monza cap that doean't close perfectly
 
Update: The winner is Morris!!!

Finally had a minute to get at Ms Triss yesterday - we're currently homeless - last house closed last Tuesday and we don't get the new one till Sept 8 - so, everything in storage and the car at a friend's house.

So, drove her till the conditions were re-created. hooked up a spark tester (a MUST-HAVE BTW) and checked - looked good, swapped the rotor just in case. - no change. swapped the coil just in case - no change. Pulled the float lid - lots of gas - started the engine to see if it would drain and run - forgot to re-hook up gas line - lots of flow :wall: - clean up spill, clean needle etc. etc. - no difference. Take cover off aircleaner, stare at it for divine inspiration, put hand in front to check vacuum - car runs like crazy! Maybe it's vacuum? tighten all the bolts on the manifold, on the carb and Bob's your uncle - who knew you needed to retighten things periodically :wall:

So what I think was happeneing was that the car ran when cold but as it warmed up things expanded and gaps opened causing the problem.

anyway, drove about 30 miles and so far so good - thanks for all your help all!
 
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