tri carb problems

[britman]

working with a friend on his 62 tri carb. cannot get smooth acceleration/fast running-still backfires some as though it is too lean. start up and idle is fine. all potential contributors check out ok (ignition, vacum, compression, etc). any suggestions?
b.davis

 

[JodyFKerr]

Check your fuel delivery, it sounds like you've got a mucky fuel filter or dirt in the carb

 

[britman]

thanks, done that-even set up a separate fuel supply, checked pump output, etc

 

[Brinkerhoff]

I have a tricarb Healey too. If you think the fuel system is ok, replace the condensor in the distributor. The balance tube on the manifolds can be problematic but you've probably checked that. Did this problem just start or is it something that developed gradually? Kevin

 

[NIB]

My advice would be to measure the CO% , you are probably running too lean. CO% should be 5.5-6.5 %.

 

[Patrick67BJ8]

thanks, done that-even set up a separate fuel supply, checked pump output, etc

Look for a infrequest contributors Healey post to the forum...goes by "Galen", (I think). He had a very odd problem with his tri-carb and it was something you wouldn't think of.
Patrick

 

[anthony7777]

patrick, i believe galen solved "his" problem by setting the timing with vacum hooked up. why?,how?

 

[Patrick67BJ8]

patrick, i believe galen solved "his" problem by setting the timing with vacum hooked up. why?,how?

I'm not sure about the why and how, but it would be good if he were to chime in and tell us as I remember it was a very interesting fix to a very complex problem. The troubleshooting to the solution was very interesting!
Patrick

I'll try and PM him as he is a member of our local club here in Texas.

 

[anthony7777]

patrick, i believe galen solved "his" problem by setting the timing with vacum hooked up. why?,how?

I'm not sure about the why and how, but it would be good if he were to chime in and tell us as I remember it was a very interesting fix to a very complex problem. The troubleshooting to the solution was very interesting!
Patrick

I'll try and PM him as he is a member of our local club here in Texas.

i remember him doing everything that one could try to solve the problem i.e. fuel pump/seperate fuel supply, coil, wires, carb bowl, filter, condenser, etc, and found that timing with his vacume hooked up seemed to solve the problem, i suspect several things were contributing.

 

[Patrick67BJ8]

patrick, i believe galen solved "his" problem by setting the timing with vacum hooked up. why?,how?

I'm not sure about the why and how, but it would be good if he were to chime in and tell us as I remember it was a very interesting fix to a very complex problem. The troubleshooting to the solution was very interesting!
Patrick

I'll try and PM him as he is a member of our local club here in Texas.

i remember him doing everything that one could try to solve the problem i.e. fuel pump/seperate fuel supply, coil, wires, carb bowl, filter, condenser, etc, and found that timing with his vacume hooked up seemed to solve the problem, i suspect several things were contributing.

One thing about the Healey is that you can have several things not performing up to par and the car runs fine, but it's the last piece of malfunctioning straw that finally breaks and the car seems to need everything replaced to get it running properly again.
Patrick

 

[BlueRidge1]

Britman,

I also have a 62 Tri Carb and was having a problem with it popping on acceleration and thought it was a lean carb. The problem was in the valve adjustment I simply had one of the intake valves set to tight and I guess it wasn't fully seating on the closeure causing a pop back through the center carb. If i remember correctly I set them cold at .015. (Better to have them to loose than to tight) Please post what you find for future reference.

Bob

 

[Patrick67BJ8]

patrick, i believe galen solved "his" problem by setting the timing with vacum hooked up. why?,how?

I'm not sure about the why and how, but it would be good if he were to chime in and tell us as I remember it was a very interesting fix to a very complex problem. The troubleshooting to the solution was very interesting!
Patrick

I'll try and PM him as he is a member of our local club here in Texas.

i remember him doing everything that one could try to solve the problem i.e. fuel pump/seperate fuel supply, coil, wires, carb bowl, filter, condenser, etc, and found that timing with his vacume hooked up seemed to solve the problem, i suspect several things were contributing.

One thing about the Healey is that you can have several things not performing up to par and the car runs fine, but it's the last piece of malfunctioning straw that finally breaks and the car seems to need everything replaced to get it running properly again.
Patrick

Here's the thread. B esure to read all the way through it(including all the posters who were wrong), and see what he did to fix the problem.
https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/681447/3
Patrick

 

[Galen]

A simple way to check and set timing is take a vacuum reading with ports located at the carbs. Depending on elevation factors you should be reading 18 to 20 inches mercury. Max reading with engine warm @3000 rpm.

My car with new rebuilt and pristine fuel system was sputtering at 3000 rpm. Everything pointed to a fuel issue.

After 3 months of agony the $15 Harbor Freight Vacuum gauge measured only 12in merc. Not enough vacuum to pull gas through the carbs. Enough up to 3000 rpm but no more.

Please read the thread referenced in Pat Yost's reply. Keoke was very dead on in his response's there.

Hope this helps

Galen

 

[Galen]

I guess I didn't finish. We advanced the timing to a point of achieving the highest vacuum reading at 18 in merc. The car runs wonderful.

The whole world is a vacuum pump.

Keoke explains in the previous threads why the timing mark was off. Thanks Keoke and B Blades

Galen
62 tri carb

 

[Bob_Spidell]

...
After 3 months of agony the $15 Harbor Freight Vacuum gauge measured only 12in merc. Not enough vacuum to pull gas through the carbs. Enough up to 3000 rpm but no more...

A minor technical nit: vacuum decreases as the throttle opens--at WOT you'll probably only have about an inch of vacuum (typical for most stock manifold induction systems). Your problem wasn't lack of vacuum per se, but that your timing was way off, probably retarded, which caused the lack of power at 3,000rpm. By setting timing with the vacuum gauge you got it correct, possibly as good as it could be for your engine and cam, etc. Did you check timing before and after with an advance meter?

On aircraft with constant-speed propellers power is measured--in part, engine speed is also used--by manifold pressure, which is equal to atmospheric pressure when the engine isn't running and is the inverse of a 'vacuum' reading. For example, standard atmospheric pressure at sea level is 29.92 inches of mercury, and as you close the throttle the manifold pressure drops, increasing the difference between atmospheric pressure and hence increasing vacuum. At WOT the difference is about an inch.

 

[Galen]

Bob
We initially set the timing based on the timing mark. The car ran good up to 3000 rpm. Once we adjusted the timing based on achieving max vacuum the timing mark on the pulley was no where in sight.

galen 62 tri carb

 

[Johnny]

Make sure the intake manifold seals are properly in place and tight. Also check that the carbs seal properly as well.

 

[Galen]

Britman

any progress on your healey?