Carb. Adjustment

MichaelMullis

Petty Officer 2nd Class
Joined
Sep 18, 2003
Messages
131
Need help. I was replacing the electric choke on my 1959 35hp johnson this weekend, had to go into house for a few minutes, when I came back out the 6 year old from next door was sitting in the boat "working on my carb".He has been watching and helping me work on this motor and boat for a couple of months. He told me that he "turned this in for me". "This" being the High speed adjustment.This being said, what is the correct method to set both low and high speed adjustments.I just replaced thottle control linkage and was going to take to lake on sunday to fine tune adjustments. By the way He did not remember how many turns he made on High speed knob. What I want to do is reset both low and high speed.Thanks for any advice in advance.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Carb. Adjustment

Try starting out at one and a half turns each and go from there to fine tune it. You may have to turn them in some as this may be too rich.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Carb. Adjustment

The following may be useful to you.<br /><br />(Carburetor Adjustments - Two Adjustable N/Vs) <br />(J. Reeves)<br /><br />Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns. <br /><br />Setting the high and low needle valves properly: <br /><br />NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.<br /><br />(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting. <br /><br />(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. <br /><br />When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

MichaelMullis

Petty Officer 2nd Class
Joined
Sep 18, 2003
Messages
131
Re: Carb. Adjustment

Thanks Rick, Joe. I have one more question, bet you hear that a lot HU. When I replaced the linkage from control box to motor, I tried to set so that at full forward, motor linkage was at wide open, at mid point motor linkage was at start, and at full reverse, motor linkage was at slow. This did not work out to be exact but I got as close as possible to what I thought would be correct. Is this the way it should be set? If not, how should I set it.<br />Any Ideas how fast this 35 will push this 15' Duracraft.This is replacing a 15 gamefisher.<br />Thanks<br />Michael
 

MichaelMullis

Petty Officer 2nd Class
Joined
Sep 18, 2003
Messages
131
Re: Carb. Adjustment

Rick, Joe or anybody that knows. Please let me know about linkage setting.<br />Thanks
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Carb. Adjustment

Baitkiller.... You state in your last post "When I replaced the linkage from control box to motor, I tried to set so that at full forward, motor linkage was at wide open, at mid point motor linkage was at start, and at full reverse, motor linkage was at slow."<br /><br />Frankly, you've lost me. I have no idea what you're referring to. If you're saying that you've replaced the throttle cable, simply adjust the threaded trunion on the cable at the engine so that there is a nice idle rpm when in neutral.<br /><br />The range of throttle settings will take care of itself as you increase it.<br /><br />If on the other hand, if you are referring to some settings (readings) that some engines have which state reading such as Stop, Slow, Shift, Fast, Stop, etc..... those are simply for reference (which way is slow or fast). Ignore them.
 
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