Throttle Cam on 2001 2 stroke 30 hp

[Havoc25]

After buying my motor from an individual, I test ran the motor and it ran fine except I felt that the motor wasn't giving me all it had. With a closer look, I noticed that with the slack in the throttle assembly, my throttle cam wasn't allowing the carburetor to fully open up. There was about 20-30 degrees of rotation that I was unable to achieve with the tiller handle. I adjusted the cam where it opened the carb the entire way. I was wondering if this was caused by the slack in the throttle or if it was factory set? I haven't messed with the set screws behind the advancer arm but I'm nervous due to rpm limits that it will damage the motor at fully open. What should I do?

 

[Sea Rider]

Welcome to Iboats,

And that engine brand is ?......

Happy Boating

 

[Havoc25]

Nissan

 

[pvanv]

Assuming you have an NS30A4. Verify sync per the Factory service manual to confirm proper throttle and ignition timing.

 

[Havoc25]

The manual I have does not mention factory settings for timing or throttle.

 

[Sea Rider]

That model has a fixed carb cam that connects to advancer arm, it's not adjustable. Did not understand your post well. Did you play with carb's a roller arm height, with Timing Assembly link rod connected at upper portion of advancer arm or lower link rod height that connects too to advancer ? Are we speaking of the same engine shown ?





Happy Boating

 

[pvanv]

The manual I have does not mention factory settings for timing or throttle.

The Factory service manual does.

 

[Havoc25]

Yes Sea Rider that is the same motor. I adjusted the link rod which connects the top of the advancer arm and the throttle link rod to the actual throttle cam. I "shortened" the rod to take away excess slack which allows for the throttle cam to rotate about 15 degrees further and "open" the throttle lever.

 

[Havoc25]

No Title

This picture shows what I adjusted. I am wondering if the cam only rotated so far due to factory settings in respect to rpm ratings or if the slack was not allowing the carb to "open up"?

 

[Sea Rider]

Some issues :

Assume while grip was at idle position, you moved gear lever forward then full throtttled to check throttle sync, right ? If the whole throttle system had excessive side slack, you should have replaced all throttle metal & plastic parts that produced slack and maintain all factory setting. The only posssible way when adjusting carb to fully open is by means of upper arm stopper nut, not messing with carb and ignition sync.

Seems you definitely have desyncronized the whole engine, although it will start don't know if will run well. As we don't know if advance timing is over or under advanced for that fixed carb setting. Confirm if having throttle slack due to having worn plastic parts as to go from there right on.

Happy Boating

 

[pvanv]

Now that you have the sync all out of whack, start with the Factory service manual as a guide, and put the motor back to stock, then diagnose.