Shift/Throttle interlock switch problem?

jim_s

Petty Officer 2nd Class
Joined
Sep 12, 2013
Messages
105
I'm a first-time boat owner (and only been that for about 2 months now :), so please forgive my improper terminology and general ignorance in this...

I purchased a 2001 Bayliner 160 back in Sept, with a 90hp Mercury 2-stroke, 3-cylinder engine. The little tub has been running great, and we've been having an absolute blast with it.

Put it in the water on Monday to run Sta-bil and Sea Foam into it in preparation for winter mothballing. It started right up as usual, all worked fine. Shut it down, then went to start up again a while later (to drive it to the ramp to pull it out, after helping a friend w/ his boat), and it wouldn't start - turned the key, but nothing happened. After some head scratching, I realized that it was the act of putting the shift/throttle lever forward in order to start it that was the problem. (There's a little button on the pivot base of the lever, labeled "Advanced Throttle Only", which I push in, then advance the throttle for starting when the engine is cold.) With the lever in neutral, the starter would turn (but not enough gas to actually start up, since the engine had cooled down). With the lever in reverse (pushed the button to move into reverse) the starter would turn, but again, not enough gas to start up when cold. With the lever in forward (again, with button pressed while moving lever forward - as I've done for the past 2 months with no problems), the starter wouldn't turn. Finally got it started by holding the button in w/ my knee, while jiggling the lever a bit with one hand, and turning the key w/ the other.

So, it seems, from the outside, that there must be some interlock switch in there, to keep idiots (like me) from trying to start the engine w/ the prop engaged. Great feature. It seems further, however, that perhaps that interlock switch has reached the end of its useful life... Does this sound like a reasonable diagnosis? Can anything be done to resolve the problem, w/o having to replace the shift/throttle assembly? (It says 'Mercury' on the lever housing, but I can't find any model number or such on the parts that are interior to the cockpit, nor the part that is mounted up under the side of the boat where the cables and wires go into the unit.)

Would appreciate input/advice on this - Thanks!!
 
Last edited:

dwco5051

Commander
Joined
Sep 14, 2008
Messages
2,452
Re: Shift/Throttle interlock switch problem?

It sounds like you have the problem figured out that it is internal to the control box. Now the question is what to do to fix it. What looks relatively simple from the outside is a mechanical wonder on the inside with lots of moving parts. Cams, followers, switches, bushings, etc. Opening it up and figuring out what is going wrong can be daunting if you have never worked on one before. If you decide to do it yourself you need an exploded diagram of the workings and pay close attention to how everything came apart because there is lots of wrong ways to put it back together but only one right way. It appears that the switch itself is not defective but either it is out of position or the part that activates it is out of kilter.
 

jim_s

Petty Officer 2nd Class
Joined
Sep 12, 2013
Messages
105
Re: Shift/Throttle interlock switch problem?

Ah, cool - Thanks for the links to the diagram and parts list. I've definitely got a 'Commander 3000 Classic' - just need to figure out which variant (from a quick look, I can't tell the difference between any of the 3000 Classic units listed on that page?), and which bit inside. (The diagrams don't make it clear what the little center button engages inside.

Thanks for the warning on the internals' complexity, too - good to know, before I have springs and other bits flying around. <:)
 
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