Throttle Adjustment ??

[rsp95]

New boat owner with a 1974 50hp Mercury Thunderbolt. My question is how far out can I adjust the throttle adjustment screw? The prior owner had it less than half way out so the motor wasn't allowed to be opened up.

 

[achris]

Re: Throttle Adjustment ??

First thing to do is buy a Merc genuine service manual and go through the full throttle and timing synchronization adjustments.... That will them have all the screws in the right place....

Chris.........

 

[mthieme]

Re: Throttle Adjustment ??

Until it either bottoms out or falls out.
The butterfly only goes so far too.
My 35 is adjusted so the butterfly is closed and it idles fine. (gotta clean out the idle circuit).
This screw (front right facing the motor) should have nothing to do with anything above an idle.
Sounds more like a cable adjustment...I'm assuming it's not a tiller(?).

 

[rsp95]

Re: Throttle Adjustment ??

I just ordered a manual for the motor so I'm not yet familiar with the engine terminologies, I apologize. I basically turned out the screw so that I'm able to fully utilize the throttle. When pushing the throttle forward or reverse, there is an oval unit that rotates and it has the distributor cap attached on the bottom. The screw that I adjusted limited its rotation. I'm not certain what you meant by cleaning out the idle circuit or about it not being a tiller. I hope I made sense with my explanation.

 

[Yepblaze]

Re: Throttle Adjustment ??

It sounds as if you might be adjusting the maximum timing advance stop screw.

If that is the case it could cause catastrophic damage if allowed to operate past a set standard.

The set standard is described in a service manual, and quite a bit more intricate, and lengthy than you might find described here.

 

[rsp95]

Re: Throttle Adjustment ??

Luckily enough for me, I remember the old setup location. Hopefully it's not so sensitive that it'll give me problems.