Blocked passage for the win! Nice job, bet it feels good to get that taken care of.
Trollhole troubles?
- Thread starter alaska60
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- Thread starter
- #43
Me too brother....now I can get back on your junk!
Not sure if it’s best to add to this thread or start a new one? I apologize for the wordy description but I thought it might be useful in trying to help diagnose my problem(s).
I’m having issues with a trollhole carb installed a few years ago. Purchased my 72 (10/71) about 12 years ago with a Holley carb and none of the original air cleaner parts. It ran decent with the Holley but it always seemed to backfire in the carb. Driving it on the slightest inclines would flood it. I don’t drive this truck very often and it sat parked in the garage for a while after a move to my new place. About 3 years ago I decided to get it running again and purchased the trollhole carb to try and alleviate some of those previous issues. After bolting it on, the truck started right up and seemed to run pretty well but it was burning super rich. Horrible gas mileage and unburned fuel smell out of the exhaust. Parked it for another few years.
Fast forward to coronavirus and a lot of time to read these super helpful forums and put some work into my neglected cruiser. After a lot of reading on the forums I decided to clean up my fuel system. New fuel filter, new fuel lines, dumped the bowl of the carb (a little bit of debris came out), new spark plugs (old ones head a good amount of black carbon buildup on them). Truck starts right up but continues to burn super rich. Also noticed that the fuel cutoff solenoid had power but when unplugged the engine continued to run. After some more digging I came across a thread where somebody mentioned the gasket the carb sits on was interfering with the butterfly valves. Sure enough I removed the carb and noticed this to be the case with mine as well. Trimmed the gasket with a razor blade to clear the valves better. While it was off I sprayed it down with carb cleaner and made sure the jets were clear. Bolted the carb back on and gave it a try. Actually had to use the choke to start it this time, which I haven’t had to do the entire time this trollhole has been on. Ran it with the choke pulled for a while to get it warmed up. Terrible unburnt gas smell seems to have gone away. Also the solenoid actually kills the engine when unplugged now. Took a very long time to warm up. Choke opened back up and started to take it on a test drive and felt a serious lack of power and backfiring in the carb again.
I have to rev it up pretty high and feather the clutch or it seems to bog down and backfire in the carb. Got on the freeway but it wanted nothing to do with that. Took 2nd gear up to about 40-45 to keep the revs up but once I grabbed 3rd it started backfiring under the load of trying to keep up on the freeway. Never made it above 50mph.
Before I go any further and potentially cause any damage to the engine or carb I thought I’d try reaching out to anybody that can offer me some advice.
A few things I see consistently come up with these issues are checking for vacuum leaks/readings and checking timing. I don’t own a timing gun but have a friend that said I could borrow his. As for checking vacuum where do you hook a gauge up? I have a port on top of the intake manifold that has a rubber cap on it. Is this the spot to check it?
I’m having issues with a trollhole carb installed a few years ago. Purchased my 72 (10/71) about 12 years ago with a Holley carb and none of the original air cleaner parts. It ran decent with the Holley but it always seemed to backfire in the carb. Driving it on the slightest inclines would flood it. I don’t drive this truck very often and it sat parked in the garage for a while after a move to my new place. About 3 years ago I decided to get it running again and purchased the trollhole carb to try and alleviate some of those previous issues. After bolting it on, the truck started right up and seemed to run pretty well but it was burning super rich. Horrible gas mileage and unburned fuel smell out of the exhaust. Parked it for another few years.
Fast forward to coronavirus and a lot of time to read these super helpful forums and put some work into my neglected cruiser. After a lot of reading on the forums I decided to clean up my fuel system. New fuel filter, new fuel lines, dumped the bowl of the carb (a little bit of debris came out), new spark plugs (old ones head a good amount of black carbon buildup on them). Truck starts right up but continues to burn super rich. Also noticed that the fuel cutoff solenoid had power but when unplugged the engine continued to run. After some more digging I came across a thread where somebody mentioned the gasket the carb sits on was interfering with the butterfly valves. Sure enough I removed the carb and noticed this to be the case with mine as well. Trimmed the gasket with a razor blade to clear the valves better. While it was off I sprayed it down with carb cleaner and made sure the jets were clear. Bolted the carb back on and gave it a try. Actually had to use the choke to start it this time, which I haven’t had to do the entire time this trollhole has been on. Ran it with the choke pulled for a while to get it warmed up. Terrible unburnt gas smell seems to have gone away. Also the solenoid actually kills the engine when unplugged now. Took a very long time to warm up. Choke opened back up and started to take it on a test drive and felt a serious lack of power and backfiring in the carb again.
I have to rev it up pretty high and feather the clutch or it seems to bog down and backfire in the carb. Got on the freeway but it wanted nothing to do with that. Took 2nd gear up to about 40-45 to keep the revs up but once I grabbed 3rd it started backfiring under the load of trying to keep up on the freeway. Never made it above 50mph.
Before I go any further and potentially cause any damage to the engine or carb I thought I’d try reaching out to anybody that can offer me some advice.
A few things I see consistently come up with these issues are checking for vacuum leaks/readings and checking timing. I don’t own a timing gun but have a friend that said I could borrow his. As for checking vacuum where do you hook a gauge up? I have a port on top of the intake manifold that has a rubber cap on it. Is this the spot to check it?
That is the spot, check manifold vacuum.
Have you pulled the spark plugs and looked at them for signs of lean or rich burning? Yes, do a timing check. I'd consider checking dwell too, if the points are suspect, and the distributor is old, or not upgraded to electronic ignition. Have you checked your valve lash?
Have you pulled the spark plugs and looked at them for signs of lean or rich burning? Yes, do a timing check. I'd consider checking dwell too, if the points are suspect, and the distributor is old, or not upgraded to electronic ignition. Have you checked your valve lash?
I’d recommend cutting and pasting your question into a new thread and delete this post. You’ll get a lot more feedback.
I haven’t checked any of the above yet Except for plugs. Just finished the test drive an hour ago. Thought I’d look for some advice for things to check tomorrow after work when I hopefully have a bit of daylight. I don’t have a vacuum gauge necessarily but I have a digital gauge I use to check natural gas pressures. Can I possibly use that and set it to mBar or inches water column? What scale are you reading and what numbers should I be looking for?
The plugs I pulled a few days ago and as I mentioned they were covered in black soot and/or carbon build up. I put new denso plugs in it over the weekend. It’s only been running for a few miles since the new plugs so I haven’t bothered to pull them to check them yet.
My buddy is going to help me set timing tomorrow. I was under the impression I’m looking for 7 past tdc? My distributor has a dial on the back to turn for advance or retard. Not sure if it’s original. I had the pleasure of meeting Marv Spector years ago and I remember he messed around with that dial a bunch to try and help it run better. He basically told me at the time the Holley was garbage, which is what eventually led to me trying out this trollhole.
The plugs I pulled a few days ago and as I mentioned they were covered in black soot and/or carbon build up. I put new denso plugs in it over the weekend. It’s only been running for a few miles since the new plugs so I haven’t bothered to pull them to check them yet.
My buddy is going to help me set timing tomorrow. I was under the impression I’m looking for 7 past tdc? My distributor has a dial on the back to turn for advance or retard. Not sure if it’s original. I had the pleasure of meeting Marv Spector years ago and I remember he messed around with that dial a bunch to try and help it run better. He basically told me at the time the Holley was garbage, which is what eventually led to me trying out this trollhole.
Post up pics of the plugs, the old ones, and the new ones. My guess is that the plugs are fouled from oil, and the plugs are actually shiny black. It would be hard for a trollhole carb to be running rich and carbon fouling from too much fuel. However, make sure that your fuel line is right in the center of the window on the bowl.
15 in of Hg or more is minimal. 7 degrees before top dead center - or on the ball bearing on the flywheel, at 650 (ish) rpm.
Take a look at the distributor cap and rotor. Make sure that the spark plug wires don't have excessive electrical resistance.
15 in of Hg or more is minimal. 7 degrees before top dead center - or on the ball bearing on the flywheel, at 650 (ish) rpm.
Take a look at the distributor cap and rotor. Make sure that the spark plug wires don't have excessive electrical resistance.
Fuel level in the sight glass has always been at half full. Based on what I’ve been reading I don’t think I have a float issue. Also to note the trollhole wasn’t really the issue of the truck running rich. It was my bad installation of it and the gasket holding open the valve. Now that I’ve trimmed the gasket I exercised both butterfly valves and they operate smoothly. I just need to figure out the backfiring in the carb and the loss of power.
I’ll see if my gauge reads in mg tomorrow and if so I’ll throw it on there.
If I do need a valve adjustment which seems to be a common issue should I be proactive and get a new valve cover gasket? I’ve never removed mine and worry it might leak when I re-install.
I’ll see if my gauge reads in mg tomorrow and if so I’ll throw it on there.
If I do need a valve adjustment which seems to be a common issue should I be proactive and get a new valve cover gasket? I’ve never removed mine and worry it might leak when I re-install.
The valve cover gasket might be good if it isn't welded to the head, or brittle. You might want to get an extra gasket if you need this as a daily driver.
Post up a pic of one of the newly installed plugs.
Post up a pic of one of the newly installed plugs.
Valves, vacuum, timing.
I’d get it up to running temp best you can and adjust the valves. Then check out what your vacuum levels are. The needle should be steady.
I’d get it up to running temp best you can and adjust the valves. Then check out what your vacuum levels are. The needle should be steady.
See post #47 on First valve adjustment on my 78 FJ40 ...
^ on extra valve cover gasket. Don't forget to torque the valve train base mount bolts.
^ on extra valve cover gasket. Don't forget to torque the valve train base mount bolts.