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Old johnnyrudes ?

M

Mikey N.C.

Advanced Contributor
Question on older late 80'-90's . 30-40-50-60-70 hp. 2 or 3 cylinders. If you rebuild carbs. Have 170- 185 psi compression. Have required voltage from charge coils, stator ect. Have required fuel pressure from VRO or deleted VRO with pulse pump. If you link and sync. per manual. In that adjustments, different motors call for a certain measurements for trigger , from socket and ball to other socket and ball. After you've set first preliminary idle screw adjustment. With new cam bushing for trigger. And motor will not idle unless you shorten trigger linkage and advance trigger , say 1/4-3/8-1/2 in.
I'm not understanding something about this. Is it the plastic guide ring around hub under flywheel. I have extensive knowledge on 4 stroke diesel motors ( mechanical) and the old Detroit 2 stroke motors.
I've seen these johnnyrudes triggers advanced on alot of old motors.
I'm not understanding , what's the root cause of this.
Any advice would be appreciated. THANKS.
 
Well highly doubtful your compression is that high on any of those motors. Idle speed is set by the timing advance on OMC motors. That plastic ring is a bushing for the timer base to ride on.
 
Rite , timing base, rides on plastic on some. I understand that idle speed is adjusted by long screw with lock nut. I can set one and get it to run. That wasn't my question. Maybe I can't explain well enought. If timing base has a set distance, per manual between, ball to ball ( with snap adjustable sockets) on linkage . why when motors get older , why does timer base have to be moved forward??? Cause if you loosen screw for cam on carb. To keep butterflys closed.
By turning idle timing screw , you are only moving timing base forward. If you set by manual , and align carb cam with marks for carb cam, all you are doing is opening butterflys a little.
Hope that makes sense. I can adjust. In lines ,v4 an v6 to run . Question why does timing base have to be moved if it had a original setting?
 
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