1954 25 hp Evinrude Big Twin

[Monkeyriot]

ok, I am missing something here, I got my 1954 25 hp Big Twin started.....yeah! The only question is......um, how do I get it to shut off?????

 

[1946Zephyr]

Re: 1954 25 hp Evinrude Big Twin

twist the throttle to the "OFF" position. If that don't work, pull the choke.

 

[Monkeyriot]

Re: 1954 25 hp Evinrude Big Twin

twist the throttle to the "OFF" position. If that don't work, pull the choke.

So is that what the murcury switch is for, to throw the electric choke?

 

[boobie]

Re: 1954 25 hp Evinrude Big Twin

No, the mercury switch is there to drop a cyl if the mtr over revs. By turning the throttle to off you are retarding the timing so the mtr will not run anymore. As Zephyr said, then pull the choke. There is no electric choke on that mtr.

 

[Monkeyriot]

Re: 1954 25 hp Evinrude Big Twin

So maybe the guy who I bought it from added an after market choke selinoid......also where should the mercury switch wire connect to?

 

[F_R]

Re: 1954 25 hp Evinrude Big Twin

Actually, there is an electric choke if it is an electric start motor. I would assume it is electric starting if there is a mercury switch.

Actually, the mercury switch is there to prevent electrically starting the motor at high throttle settings. It has nothing to do with either stopping or over revving the motor. It should not be necessary to choke it to stop it. Choke-to-stop began with newer motors that had preset idle speed capabilities. In that case, you could not slow it down to stall, so you had to choke it. Not applicable to the 1954 though.

There is a vacuum cut-out switch. That is there to prevent over revving the motor.

One thing is correct---you stop the motor by turning the throttle to such a slow setting that the motor simply stalls.

 

[Monkeyriot]

Re: 1954 25 hp Evinrude Big Twin

I see now F_R, you are correct it is an electic start. What you said makes total sense now. Thanks everyone for the feedback

 

[boobie]

Re: 1954 25 hp Evinrude Big Twin

FR. What about the mtrs that had two mercury switches on them side by side? What was their function?

 

[lindy46]

Re: 1954 25 hp Evinrude Big Twin

No, the mercury switch is there to drop a cyl if the mtr over revs. By turning the throttle to off you are retarding the timing so the mtr will not run anymore. As Zephyr said, then pull the choke. There is no electric choke on that mtr.

Actually the mercury switch just prevents the starter from firing if the throttle is advanced too far. The vacuum cut-out switch cuts out a cylinder when the motor over-revs.

 

[Monkeyriot]

Re: 1954 25 hp Evinrude Big Twin

I put a fuel pump on this motor what do I do with the return line for the old pressure tanks? Cap it off?

 

[levi_tsk]

Re: 1954 25 hp Evinrude Big Twin

which swap did you do ? the transfer cover?
transfer cover swap -plug the hole
mikuni fuel pump swap - take the check valves out of the intake manifold and plug up one of the holes with a vacuume cap

i dont advise drilling the old cover because youll have to get the holes JUST right and thats a hard one to do you should be able to get a transfer cover from one of the aomci guys OR off ebay

 

[F_R]

Re: 1954 25 hp Evinrude Big Twin

FR. What about the mtrs that had two mercury switches on them side by side? What was their function?

That would be 1958-61 models. One mercury switch was to prevent starting with advanced throttle, and the other was to disable the vacuum cut-out switch at higher throttle settings. That was because under certain conditions (cruise throttle) the vacuum would be high enough to cut out the cylinder when not intended, causing a miss at certain speeds.

 

[F_R]

Re: 1954 25 hp Evinrude Big Twin

I put a fuel pump on this motor what do I do with the return line for the old pressure tanks? Cap it off?

Yes.

 

[boobie]

Re: 1954 25 hp Evinrude Big Twin

Thank you F_R for the refresher. I knew one was starting and the other for the over-rev cut out but couldn't remember the yrs.