Are you F-ing serious?

#21
Thats because people try to adjust them like a float style carb, its a different animal, but not too much unlike a float bowl design you mentioned. I have dealt with these carbs for over a decade. The diaphragm is the issue and once its understood, things can become easier. With a float style carb of this nature you can adjust the float level to make tuning more pleasant, with a diaphragm you are stuck with the stiffness (or how worn out) of the diaphragm to determine what would be equated to float height. Some people will keep on sticking in new diaphragms (as mentioned here before) to keep the easy tuneability. I have found that usually the diaphragm will only wear to a point and then kindas level off (to a point of failure) . This is the same as trying to tune a float style carb with a float level thats too low (but who would ever do that, when its so easily correctable). It makes the screw adjustments more complicated as the low requires more movement and the high less as with the low level because it creates a greater overlap of fuel between the two ranges. You have to go back an forth between the two "sweet spots" of high and low to balance out the middle. It can mean the difference between starting out with an 1/8 turn on the high equaling a 10% increase of power to 1/32 turn half that increase after the bottom is dialed in. The condition of your needles can add or take away from this as a rotted and pitted needle screw will obviously be more unpredictable that a clean and solid one. The presence of fuel will always add to the breakdown/wear of the diaphragms simply by gravity and this will be significantly increased with fuel that contains ethanol as it breaks down the diaphragms material much quicker (some aftermarket brands do hold up better that others). Then you have temperature changes that effect the diaphragms flexibility, in my experience the change is less noticeable with a worn diaphragm compared to a new one. You may ask why would any would want to deal with any of this, the answer is simple.... A float style carb has its limitation of angles it can operate in compared to what is being talked about.
That's why I still do not like them,That's all I saying!. I didn't need a repair lesson on them.
This is how I like my carburetors to look like on a Tecumseh on my Rupps.

 
#24
That's why I still do not like them,That's all I saying!. I didn't need a repair lesson on them.
This is how I like my carburetors to look like on a Tecumseh on my Rupps.

I know I quoted you but that post was not meant just for you, sorry for any confusion or misunderstanding. I was just sharing some insight and expanding on what you stated . I like how your setup looks as well.
 
#25
That was infact the Lauson power products designed carb.

It goes back to the early days when Lauson was developing a line of 2 strokes ( one was a rather interesting radial 3 banger that recently resurfaced found in the Techumseh engineering building attick ). Anyway once Tech had managed to diegst and fully rationalize Lauson ( or in my opinion drag down the toilet ) in a take over bid this carb, an earlier 2 stroke and what later became the uniblock series of 2 stroke engines were were incorperated into the tech line.....

These are actualy a good carb but you need to know what carb you want in the series. This is the one you want with adjustable low and high speed jets.
Its off probably a mower from the look of the choke.
Its small....
Used with a second single adjustment version in a progressive linkage dualy set up they work well.

This carb was never intended for a HS40

They used to be like assholes and every shop had a box full of them....
 
#26
They used to be like assholes and every shop had a box full of them....
I pitched my share of them because some were just "bad", either slag from the casting process or garbage you could never get out, unless you wanted to pop and reset a welch plug. Not having to go thru changing a jet has its value.
 
#27
I had patients and stripped them...

Its not Lauson's fault they were gobled up by Tech and turned shine to shit. They made some good stuff, on par with the best Kohlers, Onans and Iron block engines of the day.

You know that Uni-Block engine could have been something too.
If it had been stronger it could have been something the westbend. I tried to make something of one once....
Used the piston port version with the high compression head from the Ice auger version and the read plate and carb of the mower version ( two carbs ) and igntion parts from the marine version.....

Net result flying bits of metal cause of the weak rod and weka bearings and weka case....
But damb they had potential. Typical of Tech to fook up a good Lauson design.

Side note:
The Lauson radial.
Showed a picture of that to my old man a few years ago.
He was aware of this seems back in the 60s when he was at Mac working in the factory they were tinkering with something that looked not just a little BUT EXACTLY like the Lauson. Never went any place but they were trying to make a simple target drone engine using off the shelf parts. Eventualy they did too but it was all saw and all Mac...
 
#29
I had patients and stripped them...

Its not Lauson's fault they were gobled up by Tech and turned shine to shit. They made some good stuff, on par with the best Kohlers, Onans and Iron block engines of the day.

You know that Uni-Block engine could have been something too.
If it had been stronger it could have been something the westbend. I tried to make something of one once....
Used the piston port version with the high compression head from the Ice auger version and the read plate and carb of the mower version ( two carbs ) and igntion parts from the marine version.....

Net result flying bits of metal cause of the weak rod and weka bearings and weka case....
But damb they had potential. Typical of Tech to fook up a good Lauson design.

Side note:
The Lauson radial.
Showed a picture of that to my old man a few years ago.
He was aware of this seems back in the 60s when he was at Mac working in the factory they were tinkering with something that looked not just a little BUT EXACTLY like the Lauson. Never went any place but they were trying to make a simple target drone engine using off the shelf parts. Eventualy they did too but it was all saw and all Mac...
The uniblock is not that bad as long as you dont expect too much from it. If you keep it under 7K most will hold up. The rod cap bolts are the weak link (like some other 2 strokes with the split cap design). I cant think of any case failure I experienced that was not caused by a rod letting go. If the bearing pockets start to loosen up then...well you know, same result. They definitly have a size and weight advantage. They are what they are. The best gain with them I ever experienced (piston port) was taking about .020-.025" off the piston skirt in the area that opens the intake port, the duration change had the feel of opening up the "power range" without moving it up too far, it only worked with smaller carbs. It makes me wonder if a reed block with a small carb could keep the rpms in check with he same mod. Extending in the duration of the intake pulse with a lower flow carb could keep the rpms in a non destructive range without having to use a "softer" reed material. Thanks, now I have a headache.
 
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