Someone knows fersure. Sneezing and idle screw does little

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,025
the " missing millimeter tip" could be stuck in the ls orifice in the idle cct chamber under the dime size plug

get a new plug pull theold one out and check the side wall of the chamber where the tip normally controls the inflow of fuel to the top chamber... check utubes on cleaning these carbs.

also check the side channel feeding fuel from the carb bowl to the top idle cct.

also see older style carb low speed circuit

also see another carb side channel to the top idle cct chamber . carb clean and blow dry the side channel make certain fuel reaches the top chamber !!

at idle the crankcase vacum sucks the fuel from the carb bowl UP via the LS needle path via the (small) side channel and eventually sucks it out of the " drip" chamber with the 3 small holes. any crud in the side channel to the top will mess up idling
1711556044848.png
 

Attachments

  • CARB LS path for fuel.JPG
    CARB LS path for fuel.JPG
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  • CARB 48 HP LS side channel&gasket..JPG
    CARB 48 HP LS side channel&gasket..JPG
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Last edited:

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
the " missing millimeter tip" could be stuck in the ls orifice in the idle cct chamber under the dime size plug

get a new plug pull theold one out and check the side wall of the chamber where the tip normally controls the inflow of fuel to the top chamber... check utubes on cleaning these carbs.

also check the side channel feeding fuel from the carb bowl to the top idle cct.

also see older style carb low speed circuit

also see another carb side channel to the top idle cct chamber . carb clean and blow dry the side channel make certain fuel reaches the top chamber !!

at idle the crankcase vacum sucks the fuel from the carb bowl UP via the LS needle path via the (small) side channel and eventually sucks it out of the " drip" chamber with the 3 small holes. any crud in the side channel to the top will mess up idling
View attachment 395996
great stuff! i'm slowly learning👍
I have to buy a used needle because they don't make these anymore.
 

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
the " missing millimeter tip" could be stuck in the ls orifice in the idle cct chamber under the dime size plug

get a new plug pull theold one out and check the side wall of the chamber where the tip normally controls the inflow of fuel to the top chamber... check utubes on cleaning these carbs.

also check the side channel feeding fuel from the carb bowl to the top idle cct.

also see older style carb low speed circuit

also see another carb side channel to the top idle cct chamber . carb clean and blow dry the side channel make certain fuel reaches the top chamber !!

at idle the crankcase vacum sucks the fuel from the carb bowl UP via the LS needle path via the (small) side channel and eventually sucks it out of the " drip" chamber with the 3 small holes. any crud in the side channel to the top will mess up idling
View attachment 395996
i just read that the piece may be inside. okay, now i get that👍
 

cyclops222

Petty Officer 2nd Class
Joined
Mar 21, 2024
Messages
150
Did you ever change that thermostat? After testing it with a thermostat and apot of slowly rising water temperature ?
 

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
the " missing millimeter tip" could be stuck in the ls orifice in the idle cct chamber under the dime size plug

get a new plug pull theold one out and check the side wall of the chamber where the tip normally controls the inflow of fuel to the top chamber... check utubes on cleaning these carbs.

also check the side channel feeding fuel from the carb bowl to the top idle cct.

also see older style carb low speed circuit

also see another carb side channel to the top idle cct chamber . carb clean and blow dry the side channel make certain fuel reaches the top chamber !!

at idle the crankcase vacum sucks the fuel from the carb bowl UP via the LS needle path via the (small) side channel and eventually sucks it out of the " drip" chamber with the 3 small holes. any crud in the side channel to the top will mess up idling
View attachment 395996
Cannot thank you enough. appreciate the generosity👍
 

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
the " missing millimeter tip" could be stuck in the ls orifice in the idle cct chamber under the dime size plug

get a new plug pull theold one out and check the side wall of the chamber where the tip normally controls the inflow of fuel to the top chamber... check utubes on cleaning these carbs.

also check the side channel feeding fuel from the carb bowl to the top idle cct.

also see older style carb low speed circuit

also see another carb side channel to the top idle cct chamber . carb clean and blow dry the side channel make certain fuel reaches the top chamber !!

at idle the crankcase vacum sucks the fuel from the carb bowl UP via the LS needle path via the (small) side channel and eventually sucks it out of the " drip" chamber with the 3 small holes. any crud in the side channel to the top will mess up idling
View attachment 395996
okay, i got carb in hand. noe i understand how the tiny holes work👍👍👍👍
 

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
Did you ever change that thermostat? After testing it with a thermostat and apot of slowly rising water temperature ?
i've been scared to, bcause a friend that's helping me says i don't put it back just right i could get leaks and problems. I'll look it up in my manual.
 

arto13

Seaman Apprentice
Joined
Jan 21, 2024
Messages
37
i've been scared to, bcause a friend that's helping me says i don't put it back just right i could get leaks and problems. I'll look it up in my manual.
okay, it looks simple. i will do it.
 

cyclops222

Petty Officer 2nd Class
Joined
Mar 21, 2024
Messages
150
As with all repairs. Take pictures as you start and as you get ready to remove another part. I removed the thermostat. Had to stop for a day. I tested it in the stove pot. Then was unsure where the spring, gasket , very small pin wet back in sequence.. I called my mechanic for the sequence. He said toss the pin. Then walked me thru. Still running 20 years later.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,025
your motor is not old but the operating concepts are !!!
to read up on how carbs and old motors work you have utbes galore or
for $20 you can download the Johnson maintenance " bible" with 400 + pages of interesting reading and concepts to bring you up to speed on the modern stuff.
that is where those old pictures of carbs came from

up to you

 

saltchuckmatt

Lieutenant Commander
Joined
Jul 19, 2019
Messages
1,800
"The 3 holes" Hmmm.....pretty sure I mentioned that. The 3 holes.

In fact if you go back to my last comment you will know an extremely easy way to test if the 3 holes are plugged. (Do they drain?)

Super easy. Why are you missing these easy clues?
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,025

mower .... outboards....carbs work the same... basically

some have needles some have jets some have air orifices but they all work the same... they pulll fuel from the fuel bowl via 2 circuits HS LS
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,312
A carburetor is a simple / crude device that responds to air flowing through it.----And carburetors are not well understood.-----That is why for decades the rumour of a 200 MPG carburetor has been out there.-----Even with sophisticated computers and fuel injection we are not near the 200 MPG target.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,025
close up view old carb with needle adjustment
on newer models the bottom one is replaced with a small orifice jet everything must be 100% clean !!
1711627978313.png
 
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