Thermoquad primary shaft leak

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run a 50 micron filter after the sock and then a 2-10 micron after the pump. Dual stage filtering and be prepared to change the smaller micron filter more often. A bypass type return line system will provide constant filtering and no vapor lock situation.
 
mopowers said:
What kind of filter are you running and where? What's it look like inside?
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Its a Purolator metal filter. In the factory location. Idk what the inside looks like. I just found out about this as well. Lol ill open it up when I get a day off

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pishta said:
run a 50 micron filter after the sock and then a 2-10 micron after the pump. Dual stage filtering and be prepared to change the smaller micron filter more often. A bypass type return line system will provide constant filtering and no vapor lock situation.
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I am currently running a bypass return line that feeds back into the tank.
 
Is that filtered fuel or is the bypass behind the filter? Like on a QJ, the filter is right at the inlet to the carb. Im not suprised at the amount of rust in the bowl, I see it on most carbs I take apart. More of a talcum powder than sand grains. Nothing that would clog a needle seat but maybe some very small passage in the carb but not likely. A very good (very large) 2 micron spin on filter (Ie. Diesel spec) would probably get all that but Im not sure what flow at what PSI those filters are rated at. IIRC the Bosch Jetronic FI spec fuel filters were super efficient.
 
I wouldn't be throwing away the tank just get....
The pics of the residue in the bowl near the pri jets. If this is the same carb that has a worn pri shaft, then that has a lot of miles on it & the residue has probably taken years to accumulate; probably normal over a long period of time. Just clean out the tank.
 
Bewy said:
I wouldn't be throwing away the tank just get....
The pics of the residue in the bowl near the pri jets. If this is the same carb that has a worn pri shaft, then that has a lot of miles on it & the residue has probably taken years to accumulate; probably normal over a long period of time. Just clean out the tank.
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The carb is a fresh rebuild it barely has any miles on it. I cleaned the tank out when I put the car back together it was in pretty bad shape inside I must not have gotten it all out. The car sat with a half a tank of gas for 20 years and that just turned to nasty goop and rust
 
pishta said:
Is that filtered fuel or is the bypass behind the filter? Like on a QJ, the filter is right at the inlet to the carb. Im not suprised at the amount of rust in the bowl, I see it on most carbs I take apart. More of a talcum powder than sand grains. Nothing that would clog a needle seat but maybe some very small passage in the carb but not likely. A very good (very large) 2 micron spin on filter (Ie. Diesel spec) would probably get all that but Im not sure what flow at what PSI those filters are rated at. IIRC the Bosch Jetronic FI spec fuel filters were super efficient.
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The bypass is in the filter its one of the factory style 3 prong filters the in and out are inline with the bypass coming out the side and going back to the tank.

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not sure if the bypass is pre or post filter but if you know you got a rusty tank, start there. remove tank and pickup and put some small rocks in there. Tape up the pickup hole and strap it to a hose real and turn it for as long as you can. The rocks will act as the media and chip off the rust flakes that the cleaning didnt get. Once your done, put some diesel in there turn a few more times and rinse until it comes out clean. Not sure what you can do otherwise to clean the inside of a tank. That filter probably is working, its just not that low of a micron level. Ford Diesel filters are 10 and 4 micron rated! Spin on post pump filters are your best bet filtration wise but are huge, or the threaded barrel EFI ones.
 
dartfreak75 said:
The carb is a fresh rebuild it barely has any miles on it. I cleaned the tank out when I put the car back together it was in pretty bad shape inside I must not have gotten it all out. The car sat with a half a tank of gas for 20 years and that just turned to nasty goop and rust
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My experience with autos sitting for a period of time, is the old fuel turns into, what I call shellac, not rust. I have taken the tanks out several time and cleaned them with lacquer thinner, but still having the crud running through the lines. Was does work after cleaning out the tanks the best I can is tie strapping a sock at the end of the pickup. Gives more of an area for a primary filtering, then the stock one. Been running my 340 with that procedure for years now, in my van.
 
pishta said:
not sure if the bypass is pre or post filter but if you know you got a rusty tank, start there. remove tank and pickup and put some small rocks in there. Tape up the pickup hole and strap it to a hose real and turn it for as long as you can. The rocks will act as the media and chip off the rust flakes that the cleaning didnt get. Once your done, put some diesel in there turn a few more times and rinse until it comes out clean. Not sure what you can do otherwise to clean the inside of a tank. That filter probably is working, its just not that low of a micron level. Ford Diesel filters are 10 and 4 micron rated! Spin on post pump filters are your best bet filtration wise but are huge, or the threaded barrel EFI ones.
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I did that process i made a giant vibrating tumbler and put rocks nuts and bolts in the tank and let it tumble for a couple hours and then washed the tank out with dawn and water.
 
dartfreak75 said:
To be safe do yall think I should replace the pump too? If there is that much in the carb the pump has to be full of sediments right?
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I dont know if there is a leather capped acelerator pump available, it there is I would buy one.
 
I pulled the tank today and its bad. Really bad. The tank its self doesn't look that. At all but the sending unit and the filler neck is rusted bad. I don't understand how this happened. I cleaned everything before reinstalling it and have only used none ethanol gas in it. But the sending unit is covered in scale and rust.
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pishta said:
not sure if the bypass is pre or post filter but if you know you got a rusty tank, start there. remove tank and pickup and put some small rocks in there. Tape up the pickup hole and strap it to a hose real and turn it for as long as you can. The rocks will act as the media and chip off the rust flakes that the cleaning didnt get. Once your done, put some diesel in there turn a few more times and rinse until it comes out clean. Not sure what you can do otherwise to clean the inside of a tank. That filter probably is working, its just not that low of a micron level. Ford Diesel filters are 10 and 4 micron rated! Spin on post pump filters are your best bet filtration wise but are huge, or the threaded barrel EFI ones.
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The bypass is post filter. The third nipple is after the filtration
 
I think its todays **** gas. Hygroscopic, collects moisture! Modern tanks are plastic with plastic senders, fuel pumps,everything !
 

Bewy said:
That rust is caused by water. Eth fuel can cause this, not non-eth fuel.
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It had to have came from the cleaning process then. I have not put any ethanol fuel in this car since its been back together
 
dartfreak75 said:
I found a leak in my primary shaft a while back on my thermoquad its got quite a but of play in it but I been running it anyway. I haven't ran the car much since its got cold but the other day I started it and noticed I have have a really bad vacuum leak I couldn't pin it down exactly where it is at but when I wiggle the wobbly shaft it goes away is it possible to have a vacuum leak around the shaft? Its leaking fuel so I know the bushings are bad but would i be leaking vacuum too? Thanks
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Absolutely.
It will show itself upon returning to idle...it will idle high or low...see you constantly retune the idle speed seeing it's high one day... then raising it the next when its 200-300 from lower all the sudden.
Had this issue with a demon carb. Buying a new throttle base plate now.
 
dartfreak75 said:
It had to have came from the cleaning process then. I have not put any ethanol fuel in this car since its been back together
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That doesn’t mean there isn’t water in the fuel you are buying. Alcohol gets blamed for a lot of stuff that it shouldn’t be. I wouldn’t walk one foot to buy clear fuel. It’s not worth the money.

My brother went out and bought a new Honda pressure washer. It had a steel fuel tank on it. Why steel? Who knows but it should have been plastic. Anyway, he started getting rust in the tank. So he swore off ethanol fuel, bought a new tank and next thing you know, the tank is rusty again.

The issue wasn’t the ethanol fuel, it was water in the fuel he was buying.
 
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