Throttle stop screw

crabmann

Recruit
Joined
Jan 24, 2012
Messages
3
2000 70 hp Johnson JR70 PLSSD- rebuilt powerhead,carbs,new fuel pump and fuel lines. Engine ran very well at high speeds but had significant difficulty at idle in the water. It would run for about 30-60 secs and die. If I hit the primer it would run until the fuel cleared and then quit and would die when shifting into gear. I overcame this problem by opening the low speed needles about 1/8 of a turn at a time for each carb (3). It ran good and I could shift and accelerate but it felt just a little off. I decided to go through the whole timing/linkage adjustment procedure per SELOC manual.
Found TDC and made sure pointer was correct. Removed throttle cable. Removed throttle arm-cam link. Adjusted the cam and follower and throttle plates. OK. ?Move the engine throttle lever tightly against the ?Throttle Stop Screw?. The next step is to connect the throttle cable. When I do this it pulls the lever to the spark advance back about 3/8 of an inch with the cable adjustment at max. This means that the when advancing the throttle the lever moves the 3/8? before it starts to advance the spark. Secondly the link to the throttle cam is in the max adjustment (shortest). All of this seems related to the position of the ?Throttle Stop Screw? located up under the flywheel.

My questions are how do you adjust the throttle stop screw and the idle stop screw?

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flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
8,289
The screw under the flywheel is used for setting the max timing once it is set you should not have to touch it again. There should be 2 screws with square nuts on the side of the motor for the throttle assembly. The top screw is the WOT throttle stop to set it take the airbox cover off, so you can see the carbs and open the throttle until the butterflies are at 90 deg set that screw so it stops the throttle there. The idle speed is the lower screw and needs to be set running in gear with the motor warm. The last one I worked on was a 95 model and I believe yours is similar.
 
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