TR4/4A TR4 ZS carb air/fuel initial setting procedures

[BillJoBob]

looking for setup procedure for the ZS carbs on my tr4 engine. Supposedly its pretty simple, and Haynes has a fairly detailed explaination, but im looking for some hands on experience from this forum....Thanks!
Cheers!

 

[trrdster2000]

Bill, your first problem is to center the jet, if you don't have the tool, it's a bit more difficult. Undo the nut that holds it all together a couple of flats, screw the jet all the way up while dropping the piston, it will probably freeze up before you get all the way up. DO NOT FORCE THE JET UP, IT WILL BEND THE NEEDLE!!! Keep moving the jet assembly around in small bits and you will be able to center the jet. Don't worry if you can only get it to be free at a half turn short of all the way up, as when you drop the jet after tightening up the hold in place nut all should be OK. The jet should be a 1/4 turn from 2 full turns from the top. Getting the the jet to bottom out at the top could require you to lift the piston if you are not center perfectly. Disconnect all linkage, now you are at the starting point.

Good luck,

Wayne

 

[Richter12x2]

Just spent about 3 weeks going through this exercise:

Try this document that I found - it's for the 175 I think, but the carb itself is pretty similar.

https://www.pclarkson.plus.com/downloads/Buckeye%20Stromberg2.pdf

 

[BillJoBob]

Thanks!...but these carbs were already rebuilt...I just want to make sure the fuel/air mixture is somewhat correct. In most cases, its a matter of turning the mixture screw in till theres a bind and then back it back out a turn or two or three...
cheers!

 

[BillJoBob]

Just spent about 3 weeks going through this exercise:

Try this document that I found - it's for the 175 I think, but the carb itself is pretty similar.

https://www.pclarkson.plus.com/downloads/Buckeye%20Stromberg2.pdf

This is great info...its not for non adjustable needles though...but still great info to have on hand...Thanks!

 

[BillJoBob]

Update:
Got some good gas 93...checked compression...All cylinders were good (185psi). checked all the wires..good. Pulled out the cylinders in the ZS carbs and checked the needles...seemed fine. Noticed that one cylinder goes up easier than the other? So I switched the plungers and the other carb was now more difficult to raise. What does this indicate? Could the plunger be bad? Im thinking bout getting another new plunger and comparing it to the old ones. Thought maybe we had wrong oil in the carbs, but that wouldnt make sense... Checked the timing and it seems to be off...running at about 20 degrees at idle. noticed that at TDC, the button in the distributor was advanced about 10 degrees. So I adjusted the dist to bring it back to zero. Motor idles fine, but has sluggish throttle response and wants to idle high and then shut off if i goose the gas. I reset the base idle settings on both carbs, checked the gap on the choke setting. Thinking that we have a bad carb or badly sync'd set up. Guy who rebuilt the engine and carbs is too far away to deal with for now...if all else fails, we'll just load her up on the trailer and take her back to him.

 

[Richter12x2]

Noticed that one cylinder goes up easier than the other? So I switched the plungers and the other carb was now more difficult to raise. What does this indicate? Could the plunger be bad? Im thinking bout getting another new plunger and comparing it to the old ones.

This is not standard practice from all I've read, but this is what worked for me. The cylinders in my CD150s were sticking, mostly on one side, but the other wouldn't go higher than a certain point.

Actually found it by accident, because I was just going to see if I could see anything wrong, I loosened the 4 screws on top, but since the cylinder was bound up, I heard a "clack" when it fell into place. (Hadn't even got the screws out yet). Ran it up and down by hand and it was smooth with no binding. So I tightened them all down again in an X pattern, and it was still perfect.

Repeated for the second carb, just loosened the screws, ran the cylinder up and down by hand, and retightened, firm but not gorilla tight (I have a tendency to do that) and it worked beautifully too. Started the car and they both rose pretty equally with throttle, so I called it good.

 

[poolboy]

Don't trust the timing marks on the damper. What you see as 20* could might be 12 as far as the engine is concerned.

 

[BillJoBob]

So then how do you set the timing with a light? Or do you just do it by ear? I took the carbs apart at the top...and nothing seems amiss. What oil is best for these carbs? Can we use 5w20? or 3-1 oil? Motor acts fine till I try to rev it and then it wants to just die....almost like its running out of gas. Cranks right back up...idles fine...ugh...I love british cars...lol.

 

[BillJoBob]

update 2...
Got the car running well, but still had issues with taking gas from the accelerator. Raised the gas tank, reset the base timing, closed up the mixture screws and BAM! she's running like a new sewing machine! Seems the pump was not supplying enough fuel to the carbs? But once we raised the tank about 12inches, it fixed the stalling issue. Now we just have to fix a drip from the oil sending pipe and install a tr3 fan to replace the tr4 fan thats too big.
will keep you guys updated as we go along....
Cheers!