8N wont't throttle down

ratface

Member
For those that have been following my saga I finally got the tractor to mow without losing power. Problem now is too much power. I just put a completely redone carburetor on it by a carb shop. Looks brand new. I cannot get the engine to throttle down. The first part of the throttle quadrant has very little effect on the engine speed. Once I go to full throttle moving the throttle down does not really slow the engine down much. It never goes below 900 rpm and runs as high as 2600 rpm. If I put slight pressure on the head of the idle speed adjustment screw with one finger it will immediately kick down. This throttle butterfly is not returning to it's proper position. This screw has little effect unless I screw it all the way in and then it idles like a banshee. Where to start, the governor spring, throttle rod, governor speed screw???? What order Please?
 
Sounds like sticking linkage problems. Make sure the linkage from the gov to the carb moves freely and does not bind any place. Or the gov is going bad so not controlling engine rpm
 
Ratface what carb do you have on there? I would start by adjusting the Idle speed adjustment screw or some times called stop screw for the throttle plate this is on the carb linkage? I'm Not talking about the idle mixture screw. The adjustment location depends on what carb you have. I can post a pic of were its at if you don't know need to know what carb. When you throttle down the linkage should return to the stop or in some cases be almost touching the stop on the linkage. Check & adjust your linkage so it is operating freely as old has already noted.

Byron
 
ratface........there are 3-screws to adjust on yer M/S carbie. The side pointing idlemix; the down pointing mainjet; and the BEHIND the carb idle speed that you are complaining about. Both Ford and M/S say to adjust all three screws to 1-turn. Heres how I adjust the Marvel/Schebler carbie. I set the down pointing main jet to 2-turns and LEAVITT!!! I adjust the side pointing idlemix fer FASTEST idle, NOT smoothest idle. Understand the difference??? Then I adjust the BEHIND the carb idle speed fer ennythang less than 500rpms is good. I have actually adjusted the M/S on my eazy starting 52-8N to 370rpms. ........HTH, Dell
 
The carb is a Marvel Schebler TSX 33. I followed one of Dells post on carb adjustment but 900 RPM is the slowest I can get it. If I back the Idle speed adjustment screw anymore it will fall out from being so lose. I will look closer at the linkage today.
 
if touching it helps it throttle down.. I'd be looking at linkage and governer, assuming hte carb butterfly runs smooth when not hooked up
 
You will need to adjust the governor linkage.

Start with the link between the throttle belcrank and the governor.

Dean
 
Idle screw works backwards. In for slower out for faster. Bet the stop screw on the linkage is screw in to far and will not let it idle down.
 
(quoted from post at 12:43:12 06/02/15) The carb is a Marvel Schebler TSX 33. I followed one of Dells post on carb adjustment but 900 RPM is the slowest I can get it. If I back the Idle speed adjustment screw anymore it will fall out from being so lose. I will look closer at the linkage today.

Looks like you already know what and where it is so the best advice I can give you is follow your manual closely for the adjustment of the governor & throttle linkage. You should be familiar if not intimate with the throttle to governor linkage from your past experience.
lol Byron
P.S. Your idle mixture screw doesn't sound right but it will probably run ok after you get the linkage set so the throttle plate comes back to the idle position correctly.
 

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