1978 70hp 3cyl; carb throttle lever question

[ajgraz]

Rebuilt carburetors the other night, and got to wondering...

Throttle lever on the top of the pair of carbs, part #15 in the diagram:

http://www.boats.net/parts/search/M...BURETOR LINKAGE AND CHOKE SOLENOID/parts.html

That lever is what the throttle cam engages so the butterflys will open when you accelerate. Part #16 is a "lockdown" screw that attaches the lever to the throttle shaft and allows about 45 degrees of rotational adjustability before locking the lever to the shaft.

So how do I know if the lever is adjusted properly?

I ask because the way it is currently set (and has been since I owned it) there is quite a bit of "throw" of the throttle cam before the primary pickup ever engages the lever...as in probably one third of the full throw of the handle on the control box when you go into gear. I could adjust that throttle lever so there is far less such "dead space" in the throttle handle throw. How is it supposed to be?

 

[Silvertip]

Re: 1978 70hp 3cyl; carb throttle lever question

Understand that the throttle and spark advance work together. There is a process in the service manual that is called throttle synchronization or as we tend to say on this forum "link & sync". This process is long and detailed and as a result is far too extensive to type here and the forum also respects copyrighted material so you really need a manual. You DO NOT start in the middle of that procedure. You start at the beginning and go completely to the end. Anything other than that results in a poor performing and possibly toasted engine.

 

[ajgraz]

Re: 1978 70hp 3cyl; carb throttle lever question

I do have a SELOC (yeah, I know) and I do have a hardcopy of Clams' link and sync, but other than Clams mentioning that the butterflys want to stop opening because of the screw stop, not the lever itself (that and the plastic "coupling" device between the two carbs are also butterfly stops), I see no mention anywhere about setting the lever?

Is the answer to my question, "as long as the butterflys stop via the screw stop and not the lever stop(s), it's all good?"