1990 120hp model # 1201x90b

[shamo]

Motor runs great, with inital timing advance high. But linkage is not designed to adjust inital timing with out affecting total timing at WOT.
when she gets what she wants at idel I am pushing my luck or missing at WOT due to (Too much).

How the heck can I bump up my initial timing "Take off" point without affecting the total timing setting and risk motor damage or picking up the standard "too far" advanced miss?

I know the motor was not designed to Idel way down, but I am sick and tired of the thing killing whenever I put it in gear especially when its warm.
I constantly need to re-start befor I run into rocks or other boats at the dock!

But it shure runs good with more inital timing than max will allow get it?

THE MAIN TIMEING ADJUSTMENT OR "TIMING BLOCK" MIGHT CHANGE THE "TIMING CURVE" but their I go thinking like a car guy again not a salor /marine mechanic WTF?

Thanks for the help guy's, sounds easy but it aint like a cars distributor every thing is a solid rod tied to main idel skerws therefor "Im skrewed".
in the adjustment catagory as far as I can see. :-{

 

[pnwboat]

Re: 1990 120hp model # 1201x90b

The symptom that you are experiencing (motor dies when you put it into gear) is common. As far as your question about adjusting initial timing without affect WOT timing....as far as I know, you can't. There is no distributor, so no changing the advance curve. It is what it is. Things to check:

1. Compression. Motor needs good compression to run well especially at low speeds.

2. Link & sync. Both carbs (throttle plates) need to be in perfect sync to idle well.

3. Idle mixture. Lean idle mixture will cause the motor to die when you put a load on the motor. These carburetors do not have an accelerator pump like in automobiles to prevent stumble when the throttle plates are opened up. Dirty carb will also cause this symptom.

4. Fuel recirculation system not working properly. There are some hoses and check valves that prevent fuel build up in the by-pass passages and intake area to prevent excessive fuel build up.

5. Fouled plugs.

6. Weak spark on a cylinder. These motors generate the voltage for the ignition system somewhat like a magneto. The lower the RPM's, the lower the voltage. You can check this by pulling off one plug wire at a time while idling. RPM's should drop the same amount for each plug wire pulled off. If you pull a plug wire off and it makes no difference in RPM's, there may be a problem with that cylinder.

7. Fuel pump. If the rubber fuel pump diaphragm is old and gotten stiff, or has a small leak, it may not work well at idle.

 

[pwilke]

Re: 1990 120hp model # 1201x90b

At WOT what degree do you have the timing set at?

 

[pnwboat]

Re: 1990 120hp model # 1201x90b

It depends on which ignition system you have. If you are setting the timing by cranking the motor over with the starter at WOT (static timing).

Prestolite ignition system you set it for 28 degrees advance.

If you have Mercury Thunderbolt CDI or CDM ignition system, you set it for 32 degrees advance.