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I have an older 5 H.P. Briggs Pulsa Jet on my tiller that I just bought. No spark, so I put in new points and condensor. It now would run but very rough so I cleaned out the carb and put in a new diaphram. It runs great until the gas level drops below the small pick up tube. I believe that is telling me that the long pickup tube isn't working. If my memory serves me right, the screen at the base of the long tube was crushed, how that happened, I have no idea, anyway, I tried to straighten it out but apparently there must be some internal damage within the tube. Can those tubes be replaced? Any trick to replacing them?
Thanks
 

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Some are brass and are a press fit,others are plastic tubes and are threaded,they will have a hex on the bottom to put a wrench on...the brass ones can often be cleaned after removing them (watch for a BB sized steel ball that some tubes had at the bottom that act as a check valve,dont lose it!)...I have soldered a new brass screen on the brass ones before..an old timer I know used to use a peice of nylon stocking with a wire tie on those tubes if the original screens were badly clogged..

The gas tanks on Pulsa-Jets often rot out in the "well" that the tube sits in,if that happens it usually wont start or run very well once it drops lower than half a tank..some guys suggest putting rubber hose on the end of the tube and run it right to the bottom of the tank and use a weedwhacker or chain saw type gas filter on the end of it to keep dirt from being inhaled..
 

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Discussion Starter #3
Some are brass and are a press fit,others are plastic tubes and are threaded,they will have a hex on the bottom to put a wrench on...the brass ones can often be cleaned after removing them (watch for a BB sized steel ball that some tubes had at the bottom that act as a check valve,dont lose it!)...I have soldered a new brass screen on the brass ones before..an old timer I know used to use a peice of nylon stocking with a wire tie on those tubes if the original screens were badly clogged..

The gas tanks on Pulsa-Jets often rot out in the "well" that the tube sits in,if that happens it usually wont start or run very well once it drops lower than half a tank..some guys suggest putting rubber hose on the end of the tube and run it right to the bottom of the tank and use a weedwhacker or chain saw type gas filter on the end of it to keep dirt from being inhaled..
Thank you very much. Great information
 

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I never thought about pantyhose. Just rebuilt one today & the screen was gone. I commandeered the ol ladys pasta strainer & cut a round piece out of it & soldered it.
 

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Discussion Starter #6
Re: Briggs Pulsa Jet Problem (New Questions See String)

Droping in the 1/2 inch copper cap works good also.
It was mentioned that there is a bb checkvalve in the long tube. What is its purpose? How does it work. I always thought the long tube would draw fuel up into the carb, but if there is a check valve, I would think that the check valve would prevent that from happening?

Also some have mentioned putting a chainsaw filter on the tube. On one tube, both tubes?

Thanks for the education and help.
 

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Not all Pulsa Jets hve the BB,and I've lost a few and the carbs still ran good anyway,though starting might have suffered some--I think the idea of the check ball was to help retain gas in the tube and carb's diaphram chamber so it woudn't need to be spun over a lot to start it faster..(?)..

I never tried the chain saw filter trick,not sure if both tubes are "feed" tubes or if one was a return for excess gas to return to the tank--I'd guess a filter only needs to go on one tube,the one that feeds the carb,but since both had screens originally,maybe one on each wouldn't hurt?..
 

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I don't recall the source, but I read/saw that both tubes ARE fuel inlets & the longer one is part of a lift system to maintain a set level in the upper chamber which actually feeds the metering system with a fixed volume which helps maintain a fully regulated fuel/air mixture. To be so simple in execution, these are REALLY quite sophisticated units. Think on how many problems they tend to eliminate with their lack of float & needle & seat. Of course, what takes their place is of critical importance. SO, a stiff diaphragm or valves (easily overlooked by someone more versed in the more conventional designs) can be a frustrating prospect. Tractor-Holic nailed the function of the check ball (from my same fuzzy source). I have used the stocking trick on the lower pick-up, but have not tried it on the upper. I have no evidence to back me up, but I consider the upper pick-up to be part & parcel with the mixture strength control & would keep any alteration to its form or function in the forefront of my considerations if any new conditions arose. But hey, if you can't play with it what's the use of having it around. I wouldn't recommend using that line around your wife/ol' lady; they CAN get riled!:hide:
 

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Discussion Starter #9
I don't recall the source, but I read/saw that both tubes ARE fuel inlets & the longer one is part of a lift system to maintain a set level in the upper chamber which actually feeds the metering system with a fixed volume which helps maintain a fully regulated fuel/air mixture. To be so simple in execution, these are REALLY quite sophisticated units. Think on how many problems they tend to eliminate with their lack of float & needle & seat. Of course, what takes their place is of critical importance. SO, a stiff diaphragm or valves (easily overlooked by someone more versed in the more conventional designs) can be a frustrating prospect. Tractor-Holic nailed the function of the check ball (from my same fuzzy source). I have used the stocking trick on the lower pick-up, but have not tried it on the upper. I have no evidence to back me up, but I consider the upper pick-up to be part & parcel with the mixture strength control & would keep any alteration to its form or function in the forefront of my considerations if any new conditions arose. But hey, if you can't play with it what's the use of having it around. I wouldn't recommend using that line around your wife/ol' lady; they CAN get riled!:hide:

This stocking trick you are referring to. Just regular womens nylons? Doesn't the gas eventually deteriorate the nylon?
 

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The "new" gas just might--didn't have any troubles with older leaded or unleaded fuel when I tried the nylon stocking trick..the OEM filter on the tubes appears to be some kind of plastic or fiberglass on the plastic tubes...you could use fine mesh brass screen or stainless steel screens,you can find stainless ones for pipe smoking at most any convenience store,right nesxt to the ciggarette rolling papers,you could epoxy or J-B weld them in place....I've use screens from faucets also,you can find them at home centers in the plumbing department..
 

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So far, the enhanced gas hasn't touched the Nylon. I believe that it WILL tolerate the ethanol. Look for confirmation though!
 
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