TO30 carb questions.

[CKain(MI)]

After purchasing this TO30 a year ago, I finally got a battery in it and cranked it over. I replaced the fuel bowl assy and flush tank before putting in gas. Then I removed the carb and found the float stuck 'up'. so cleaned the pivot pin and ports. I put adj screws back where I found them , at least close. Only one I not sure of is the big long needle valve. does it regulate fuel flow into the carb bowl ?? whats the procedure to adjust it. And when the engine is not running, how much movement is in the arm that pulls the carb butterfly. when not running mine has about one inch. Thanks.

 

[Ericp351]

The fwd adjustable - larger- "Thumb friendly" (often with a reference notch) is main mixture. It, well, controls main mixture- as in fuel-air. CCW= fat, clockwise = lean. Try 1 1/2 to 2 turns open from soft close for start point if "you lost the rabbit". Also look for a Stop screw- idle speed, and a small idle mix screw. If runs better with chock you are way lean. If smell gas/ dark exhaust think real fat. Good luck, and the more specific you are as to troubles the better help you can get. Only adjust 1 thing at a time- read your plugs- they talk much.

 

[CKain(MI)]

The fwd adjustable - larger- "Thumb friendly" (often with a reference notch) is main mixture. It, well, controls main mixture- as in fuel-air. CCW= fat, clockwise = lean. Try 1 1/2 to 2 turns open from soft close for start point if "you lost the rabbit". Also look for a Stop screw- idle speed, and a small idle mix screw. If runs better with chock you are way lean. If smell gas/ dark exhaust think real fat. Good luck, and the more specific you are as to troubles the better help you can get. Only adjust 1 thing at a time- read your plugs- they talk much.

that all sounds good. I think both are close but it wants squirts of start fluid to run. comp. all about 60-65.

 

[Mad Farmer]

Comp is a little low if gauge correct.

Carb throttle butterfly runs via governor and throttle linkage. Check they are free and correct.

 

[CKain(MI)]

The fwd adjustable - larger- "Thumb friendly" (often with a reference notch) is main mixture. It, well, controls main mixture- as in fuel-air. CCW= fat, clockwise = lean. Try 1 1/2 to 2 turns open from soft close for start point if "you lost the rabbit". Also look for a Stop screw- idle speed, and a small idle mix screw. If runs better with chock you are way lean. If smell gas/ dark exhaust think real fat. Good luck, and the more specific you are as to troubles the better help you can get. Only adjust 1 thing at a time- read your plugs- they talk much.

Ericp351, The thing is running on its own but rough. some lite poppin. The larger thumb friendly knob you mentioned does not seem to 'bottom out'. I see it has very fine threads and they look decent, might the threads in the carb be stripped ? Thinking I need a different carb... (good used one) if thats possible.

 

[CKain(MI)]

Anyone know what part of the Marvel Schebler the model number is on ??

 

[Jim.ME]

Anyone know what part of the Marvel Schebler the model number is on ??

Stamped into a round brass tag usually riveted to the upper body.

Edited to correct auto fill.

 

[Mad Farmer]

Anyone know what part of the Marvel Schebler the model number is on ??

In the picture, brass plate where intake connects

 

[Jim.ME]

X2 on what Mad Farmer said

 

[CKain(MI)]

THANK YOU VERY MUCH. your gas line routing is nice !!

 

[Mad Farmer]

THANK YOU VERY MUCH. your gas line routing is nice !!

Thanks. All the line from the tank, is new nickel/copper line. I have a nice flare tool. I left previous owners small shut off as it works and handy, that line was still good.

 

[Mad Farmer]

X2 on what Mad Farmer saidView attachment 76547

Thanks "preview" on my Mac is not working right.

 

[Ericp351]

Ericp351, The thing is running on its own but rough. some lite poppin. The larger thumb friendly knob you mentioned does not seem to 'bottom out'. I see it has very fine threads and they look decent, might the threads in the carb be stripped ? Thinking I need a different carb... (good used one) if thats possible.

If you think bad threads, simply remove needle screw and look down. If good- spray with carb cleaner and go. You say it runs- simply run and adjust screw in real time. I like to get it fat and screw in. Lean = power, BUT heat! Read your plugs. Just say no to a China carb- even if you are a China-man! Lean-or bad time-"Pops".............

 

[CKain(MI)]

If you think bad threads, simply remove needle screw and look down. If good- spray with carb cleaner and go. You say it runs- simply run and adjust screw in real time. I like to get it fat and screw in. Lean = power, BUT heat! Read your plugs. Just say no to a China carb- even if you are a China-man! Lean-or bad time-"Pops".............

Thank you.

 

[K.Campbell]

Take your carb back off, disassemble it again and soak it in chem dip for at least two days. Then run a wire through every hole to ensure it’s clear of any debris, then blow all holes out. If your float was stuck shut or open it signifies ( at least to me) that you have had bad gas or moisture introduced to the carb and it needs to be completely cleaned.

 

[CKain(MI)]

Take your carb back off, disassemble it again and soak it in chem dip for at least two days. Then run a wire through every hole to ensure it’s clear of any debris, then blow all holes out. If your float was stuck shut or open it signifies ( at least to me) that you have had bad gas or moisture introduced to the carb and it needs to be completely cleaned.

Thank you, I figured that +'process' was next !!

 

[Jim L WA]

Just my opinion, but all the carburetor cleaning and adjusting isn't going to help low compression.

 

[K.Campbell]

Just my opinion, but all the carburetor cleaning and adjusting isn't going to help low compression.

I agree, the compression seems pretty low. I’d run another compression test to double check. If it is still low, pull each plug out and squirt some oil in the cylinder and see if it pops up, if it stays the same then its valves, if the compression comes up after adding oil to the cylinder then its a possible ring issue. Make sure your compression checker is seated correctly, also make sure the o ring is in good shape. Run the test again and let us know what you find out.

 

[CKain(MI)]

Well all I have is the old comp tester that you hold in the plug whole. may not be accurate.. engine starts quick and runs with half choke...

 

[K.Campbell]

Ya, those aren’t really reliable. You need the type that screws into the plug hole. You’re probably fine to simply clean carb and reassemble. Give it a shot and let us know how it goes!