Just as I was finishing up today, putting the final cleaning and adjustment touches to the old 320, I notice that one of these hollow brass "grub screws" was much looser than usual. I don't know what they do, I can't work it out from the manual, so I left them alone. However, this one was so loose, it broke off.
OK, I have a few spare so I managed to carefully remove the threaded end from inside what I imagine is the emulsion tube? I also adjusted the the throttle slide and needle to the "correct" length as per the manual. In hindsight, I probably shouldn't have. That's introduced a variable where I didn't really want one!
I fitting everything back as it should be, and it kinda ran. Popped the air filter back on and no dice. She'll start on Start Ya Bastard and kinda run, but fuel is pouring out of these hollow brass grub screws. Fuel off, packed it away. Done for today.
According to the manual, I have enriched the mix by setting the throttle needle shorter. But it has been set at the appropriate length protruding from the throttle slide, and I had to take it apart to see what the length of the actual needle is, as that dictates the correct setting. Nothing else was touched. Before, when depressing the tickler, you might get a drop coming out the tube, and that was the giveaway to stop and start the mower.
I can only guess that they are "fuel compensation tubes." That is mentioned in the manual for cold starting, but it doesn't really go into detail as to what they actually do. There is just an arrow and letter pointing in the vague direction of something on the carby. It can't be much else, but I'm not sure. I assume they're for adjusting the air/fuel ratio, but I can't be sure of that either!
Any advice from the Carby Kings would be appreciated! She is so close to being "100%!"
If it helps, the "overview" photo of the carby has the air flowing from left, mixing in the carby and exiting right. In the photo showing the inner workings, the air flows from RIGHT and moving into the engine to the LEFT.
I don't collect mowers. I just require Multiple Mowing Solutionsâ„¢.
Yes the tubes are "fuel compensation tubes." so I would make sure they are not blocked up with gunk etc.
From what I remember last time I cleaned this type of carby it should have another port where I have the red arrow in the pic.
This video below mentions the fuel compensation tube but calls it a capillary tube , at 51 seconds from the start.
If fuel is flowing out the compensating tubes then I would say the fuel needle and seat are not closing off properly , there should be a tiny ball on top of a brass rod the closes the fuel off in the carby but if the ball has fallen out your float level will also obviously be incorrect ,if the needle and seat are fine then I would make sure the float level is set to the correct height.
Sometimes the fuel float has a small hole or a leaking seam and fills with fuel which stops the float shutting off the fuel.
My goodness, that was a very early EE video, I almost didn't recognise him! Thank you for posting it up, I hadn't come across it even though I enjoy his channel.
Correct me if I'm wrong, but those fuel compensation tubes do nothing else other than provide atmospheric pressure to the float bowl? And they have no adjust-ability at all? I have not worked on a carby like this before, but they appear similar to AMAL Concentrics, from what I've found online.
I ran out of time today to take it apart again and have a look. The G2 looks to work in the same way, just flipped 180? I'll have a look in my book that covers early Victa carbies. And you're correct, there is another port exactly where you put the red arrow.
I hope to get into it tomorrow after work, but no promises there.
I don't collect mowers. I just require Multiple Mowing Solutionsâ„¢.
Last time I used this type of carby I seem to remember when priming the carb the fuel will flow out the 2 tubes as long as the fuel stops when it's running and when the primer in in the non primed position the slight leak is ok.
Thanks Max. I took it apart again today to see what's what.
Those compensators keep the emulsion tube aligned. It looks like if you turn the bottom nut up too tight you can start to bend the soft metal. No obvious defects or re-assembly mistakes. Needle and lever moved freely, float seems to float. Tickler works.
Fuel then absolutely poured out in a steady trickle after I primed it. Took it apart again and saw that there was some "black" above where the needle would seat, fuel entry side, i.e. upstream. Gave it another blast with carby cleaner and it looked better. Did not reassemble to test as I figured I might try to save the brass tubes from undue stress. Going to hunt for some new gaskets tomorrow while it is all apart.
Throttle slide seems to want to stick a bit and not close. Will look at that after I've solved the leaking issue.
Some pictures attached for record if nothing else.
I don't collect mowers. I just require Multiple Mowing Solutionsâ„¢.
If the 2 compensation tubes are bending it would mean there is not enough packing gasket under the emulsion tube Mystyler ,I had a look at a carby of mine and it has 2 red fibre washers under the emulsion tube where the image above looks like it has one fibre washer but if two fibre washers are too much I would use one fibre washer and make the other out of gasket paper.
The needle and seat you have is the same as one Pope carby I have the other Pope carby of mine has a tiny ball bearing to close off the seat.
If the needle and seat still leak after it's all back together ,you can try repairing them,the needle could be put in a drill and spun while some fine wet and dry sand paper cleans the needle point.
I wasn't clear enough. The tubes can be bent by over tightening the nut on the end of the emulsion tube. Put too much "twist" into it and it looks like you can shear the soft brass. Either way, not ideal!
I tried chasing fiber washers but to no avail. Got a handful of copper and alloy ones, but I rebuilt the thing with the original fiber ones just to see, and to my surprise it works perfectly. Half pull cold start! Must have been some crud either preventing the needle from seating or the fiber washers were pinched?
It's a real shame the metal gauze filter was wrecked by the layer of varnish in the bottom of the tank. I've flushed it with fresh fuel and some metho multiple times but I'll need to come up with a long term solution. I'll either use the other fuel tap on the spare motor (looks like the original push/pull setup) or maybe install an in line filter further down stream.
On closer inspection, the two "rubber" seals on the banjo bolt were leather! They still worked...but I've replaced them with Viton o-rings. Allows some movement for slight rotation while still providing a seal.
Thanks heaps for your assistance here. There isn't much info on these things on the net and I really appreciate your input. Next step is to properly set the mix and keep the throttle block and needle moving freely.
I don't collect mowers. I just require Multiple Mowing Solutionsâ„¢.
