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To rebuild or not to rebuild, Thermoquad the question.

SamSly

Active Member
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6:04 PM
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Location
Las Vegas ,Nevada
All things considered my newly acquired 1977 b300 sportsman royal 440 beast ran pretty damn well from ridgecrest California to las vegas nevada, even pulling a 3500' travel trailer. Especially after it having sat for years growing mold or dust or whatever it was growing. Want to say thanks again for all the help with my last post on electrical issues. Couldnt have made it to be able to ask for help now without ya'lls input. Heres the scenario. . Somehow has selector switch was put to reserve and consequently the ten dollars that had been put into the what cvv I'm assuming is the reserve tank even though it looks large to me, ran out completely by my dear wife who then proceeded to try and crank it and crank it after it died on her on the road. She called my phone and I was able to walk her through toggling the toggle . Van starts up and she makes It home. The next time we gi somewhere the vam starts and drives maybe five miles and it starts acting like it's running out of fuel, bucking and coughing even a couple backfires. We pull off to a parking lot and pop the hood.not su re whst in looking for I just know that it's not empty because 20 was put into it the night before. Finally make it to look at the in line fuel filter and its clear plastic housing looks black. Take it off and blow through it then fill it with fuel from a 3 gallon can that is a necessity these days. The filter is clear and she starts right up after two twists of the key. Great for now. Four or five miles later same symptoms as before. Pull off coast to a stop and repeat with filter. Seems to be a little less black this go around and less junk coming out when I blow thru it. Make it to airport drop off the ol lady and start home. 20 miles to go. First stop gas station to dilute whatever is floating around in there some more and on my way. Acts up aom couple times but powers tjru ot and makes it to home fornthe time being. So I. Looking at the gas gauge and it's still looks low like almost empty low and that's odd considering we put around $50 to go forty miles round trip.next day I make it four miles away and same thing starts again. There is fuel.i the filter it's not super clean but not super dirty either. This time when I get in to try and start her up she just turns over and maybe coughs. I assume somehow I ran out of gas. Spend about forty five minutes waiting and cranknot a couple times to no avail. Finally I take about a gallon of gas out of the generator still packed in the back and after spraying a shot of carb cleaner in the intake of the air filter starts up and I turn around and go back to camp. This scenario repeats itself once more except I make it seven miles away, plus the four from the day before. 11 miles seems unheard of from what I've been hearing and reading but I could.be wrong, for one gallon of gas from empty the night before. An acquaintance brings me three gallons and I make it all the way back No problems until about a mile away it starts acting up and it almost sounds like a small bomb is going off under the dog house every ten or so seconds maybe every five idk. So bbn uts acying like its running out of fuel and then again it really is running out of fuel and its wanting an assist in firing up like b12 carb cleaner. Allen tg hie began happening after running a long metal gas tank located along the passenger side with the fuel fill hose coming up inside the right rear wheelwell. The selector is pointing at res and the only o th her fuel tank I see is mounted near or over the rear axle with a filler cap on the drivers rear quarter panel. So heres my question,finally. I picked up a rebuild kit but was wondering if I can just clean out the bowels maybe since she seemed to be running great before sediment or what not got into the system . I've cleaned and tuned the carbs on a Kawasaki 750 and honda 600 motorcycle but this will be my first actual car carbetor and one more thing about the engine. It looks like almost every single vacuum line is re routed, capped off to nowhere or not being used.then there is a slight leak passenger side . I'll attach pics. So any thoughts? I would.like to do the rebuild for th ed experience just it that we have to be mobile In two and a half days to pull out of here with trailer in tow. Yhank you for your patience in reading.

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Please forgive my ignorance....but what is the question?

My brain started hurting after the 3rd line.
 
Please forgive my ignorance....but what is the question?

My brain started hurting after the 3rd line.
How would I go about getting to the bowels with the least amount of disassembly because I liked how it was tuned
 
How would I go about getting to the bowels with the least amount of disassembly because I liked how it was tuned
There is no easy way to pull out the innards of that engine without upsetting the current tune settings.
 
There is no easy way to pull out the innards of that engine without upsetting the current tune settings.
And the second question was about the disconnected ad and blocked vacuum lines. Could that be causing the running out of fuel and backfiring etc
 
All things considered my newly acquired 1977 b300 sportsman royal 440 beast ran pretty damn well from ridgecrest California to las vegas nevada, even pulling a 3500' travel trailer. Especially after it having sat for years growing mold or dust or whatever it was growing. Want to say thanks again for all the help with my last post on electrical issues. Couldnt have made it to be able to ask for help now without ya'lls input. Heres the scenario. . Somehow has selector switch was put to reserve and consequently the ten dollars that had been put into the what cvv I'm assuming is the reserve tank even though it looks large to me, ran out completely by my dear wife who then proceeded to try and crank it and crank it after it died on her on the road. She called my phone and I was able to walk her through toggling the toggle . Van starts up and she makes It home. The next time we gi somewhere the vam starts and drives maybe five miles and it starts acting like it's running out of fuel, bucking and coughing even a couple backfires. We pull off to a parking lot and pop the hood.not su re whst in looking for I just know that it's not empty because 20 was put into it the night before. Finally make it to look at the in line fuel filter and its clear plastic housing looks black. Take it off and blow through it then fill it with fuel from a 3 gallon can that is a necessity these days. The filter is clear and she starts right up after two twists of the key. Great for now. Four or five miles later same symptoms as before. Pull off coast to a stop and repeat with filter. Seems to be a little less black this go around and less junk coming out when I blow thru it. Make it to airport drop off the ol lady and start home. 20 miles to go. First stop gas station to dilute whatever is floating around in there some more and on my way. Acts up aom couple times but powers tjru ot and makes it to home fornthe time being. So I. Looking at the gas gauge and it's still looks low like almost empty low and that's odd considering we put around $50 to go forty miles round trip.next day I make it four miles away and same thing starts again. There is fuel.i the filter it's not super clean but not super dirty either. This time when I get in to try and start her up she just turns over and maybe coughs. I assume somehow I ran out of gas. Spend about forty five minutes waiting and cranknot a couple times to no avail. Finally I take about a gallon of gas out of the generator still packed in the back and after spraying a shot of carb cleaner in the intake of the air filter starts up and I turn around and go back to camp. This scenario repeats itself once more except I make it seven miles away, plus the four from the day before. 11 miles seems unheard of from what I've been hearing and reading but I could.be wrong, for one gallon of gas from empty the night before. An acquaintance brings me three gallons and I make it all the way back No problems until about a mile away it starts acting up and it almost sounds like a small bomb is going off under the dog house every ten or so seconds maybe every five idk. So bbn uts acying like its running out of fuel and then again it really is running out of fuel and its wanting an assist in firing up like b12 carb cleaner. Allen tg hie began happening after running a long metal gas tank located along the passenger side with the fuel fill hose coming up inside the right rear wheelwell. The selector is pointing at res and the only o th her fuel tank I see is mounted near or over the rear axle with a filler cap on the drivers rear quarter panel. So heres my question,finally. I picked up a rebuild kit but was wondering if I can just clean out the bowels maybe since she seemed to be running great before sediment or what not got into the system . I've cleaned and tuned the carbs on a Kawasaki 750 and honda 600 motorcycle but this will be my first actual car carbetor and one more thing about the engine. It looks like almost every single vacuum line is re routed, capped off to nowhere or not being used.then there is a slight leak passenger side . I'll attach pics. So any thoughts? I would.like to do the rebuild for th ed experience just it that we have to be mobile In two and a half days to pull out of here with trailer in tow. Yhank you for your patience in reading.

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The carbeurator bowls, the difference one letter can make. Apologies for the lengthy discourse, I am new to these machines and this forum. Tell you the truth scares the **** out of me. I'll try to be more to tge point in the future. "Car broke....Fix.....Now!!"
 
If your fuel filter is black, that's not about the carb, thats ruining the carb. It looks like you drive through the desert and have no intention of servicing that motor, and the vacuum to the advance looks like its ripped off from the pix. I would certainly map out the vacuum lines and plug any ports that arent doing anything useful, and plan a simple tuneup, cap, rotor plugs, filters, etc. Honestly you could have just stirred up a ton of sh*t in the bottom of the tanks by running it out of gas. HTH, Lefty71
 
I would say your tanks (main and reserve) are full of bad gas which has a whole lot of that green mold you talked about.

You helped it along by putting new gas in it, but I bet you did not add any new gas to the reserve tank?
Your wife toggled from the main tank over to the reserve tank that most likely had worst gas in it than the main tank did. It could have been from the reserve tank to the main tank. It does not matter.
So not only were you trying to burn the old gas which will not burn,you pumped out the junk sitting at the bottom of your tank(s).

I would drain and flush both tanks and start over.

Best of luck to you.

God Bless America
Mike
 
WOT.jpg


I know a guy that can properly rebuild a Thermoquad...
Bob at "The Carburetor Factory" in Citrus Heights CA. Good guy, great skills.
 
The entire fuel system needs to be completely flushed/cleaned, then the carb can be rebuilt by some that knows what they are doing. I never had good luck with a well used Thermoquad, but others sure do.
 
If your fuel filter is black, that's not about the carb, thats ruining the carb. It looks like you drive through the desert and have no intention of servicing that motor, and the vacuum to the advance looks like its ripped off from the pix. I would certainly map out the vacuum lines and plug any ports that arent doing anything useful, and plan a simple tuneup, cap, rotor plugs, filters, etc. Honestly you could have just stirred up a ton of sh*t in the bottom of the tanks by running it out of gas. HTH, Lefty71
Appreciate your criticism but don't assume what my intentions are. You are correct as to the vacuum being all f'ed up but I got it this way. I have since yesterday tore down the carb, cleaned and rejetted them and put it back together. Tune up (distributor,rotor,plugs and wires) was just done about 500 miles ago as was new fuel filter. My issue now is i lost the pump arm and was hoping someone had the dimensions or specs son i could manufacture one. Thanks
 
I would say your tanks (main and reserve) are full of bad gas which has a whole lot of that green mold you talked about.

You helped it along by putting new gas in it, but I bet you did not add any new gas to the reserve tank?
Your wife toggled from the main tank over to the reserve tank that most likely had worst gas in it than the main tank did. It could have been from the reserve tank to the main tank. It does not matter.
So not only were you trying to burn the old gas which will not burn,you pumped out the junk sitting at the bottom of your tank(s).

I would drain and flush both tanks and start over.

Best of luck to you.

God Bless America
Mike
Thank you for your well wishes. That sounds like the best idea yet. You wouldn't happen to have the spec for the arm coming off the mechanical fuel pump would you, or perhaps know where I could find them? Thanks in advance
 
The entire fuel system needs to be completely flushed/cleaned, then the carb can be rebuilt by some that knows what they are doing. I never had good luck with a well used Thermoquad, but others sure do.
I'm afraid that's what may just happen. Afraid for my wallet. I got the sucker put back together but I'm afraid I may have lost a piece in my efforts. Any info on the dimension of the arm coming off the mechanical.fuel.pump would be greatly appreciated
 
You are going to have to replace the fuel pump if the arm came off. The arm is not a replaceable service part.
 
Second thought post a picture of what you are referring to as a fuel pump. We need to answer your question correctly.
 
I was looking at the words pump rod assembly and assumed it to be fuel, but now I'm guessing accelerator pump?

Good news is I found the arm. On the ground next to my work area.

20190821_080728.jpg
 
So I yuh honk I got the arm connected to the right place straight down pretty much. A lot of the vacuum hoses are already capped off with screws and such. Is there any of the vacuum tubing that I really cant frive without? Or better yet which ones are a priority.
 
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