50hp Mercury - throttle setting

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alexARC
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50hp Mercury - throttle setting

Post by alexARC »

Hello,

I am the happy owner of Gina who is now home in France.
There is a bit of work to do on the engine and I have never worked on a boat before.
The throttle cable seems corroded and does not move. I will probably replace it.

When I remove the engine lid, I could not really understand how it works.
This is the engine,

Image

and here is what I found,
Image

The butterfly are always fully open and does not seem to be connected to any cable + there is no air filter or grid (yellow arrow)
When I remove the throttle cable and move manually the throttle (blue arrow), the only part moving is the one pointed by the red arrow.

Maybe that's just normal?
I think I will bring the engine to a professional first (also for carb setting).

Thanks

haventaclue
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Re: 50hp Mercury - throttle setting

Post by haventaclue »

http://www.marineengine.com/parts/mercu ... ol-linkage I think this is your throttle linkage.I think there's a link arm missing,though I can't really see from the photo
no matter how bad it is,it can always get worse,I'm an optimist

TOM91
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Re: 50hp Mercury - throttle setting

Post by TOM91 »

Hi,
This is my first post. thought i'd sign up to help.
he bit in the yellow arrow is your choke, the actual throttle flaps are all inline through the carbs,
you should find that the throttle flaps open pretty much all of the way, and then the rest of the up-rev is done via timing advance.

Hope this helps...

Tom

alexARC
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Re: 50hp Mercury - throttle setting

Post by alexARC »

Thank you. Not crystal clear yet but starting to get better though it is more complex than my 125cc karting carb...

Both arms are in place. So the bottom one is connected to the throttle flaps whereas the top one to the spark advance.
Choke flaps are only connected to the solenoid.

I have also sprayed successfully wd40 in the throttle cable which was blocked.
Will power on the engine and see how it goes.

Image

TOM91
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Re: 50hp Mercury - throttle setting

Post by TOM91 »

Precisely. when you throttle up, the top arm (the one that moves the most), rotates the trigger assembly that senses the location of the flywheel and sends the appropriate signal to the spark plug controller to spark.

Then as you said the other arm moves the throttle flaps at the back of the carbs.
and then the choke is controlled by the solenoid. but possibly also by a pull cord if there is one at the top.

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Alacrity
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Re: 50hp Mercury - throttle setting

Post by Alacrity »

The first 1/3rd to 1/2 of the throttle is purely ignition advance, only then to the carbs begin to open. Outboards, due to the conditions they have to operate in, work completely different to all other 2 strokes.
Mercs are like women, no 2 are exactly alike. That's what testing is about. In general it is safer to test motors and props than women!

alexARC
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Re: 50hp Mercury - throttle setting

Post by alexARC »

indeed, it is really different.

So if I understand correctly, once I pull the throttle control forward, that should move the cable immediately which in return is moving the top arm and the bottom (after 1/3 - 1/2 of the course?)

I am not sure it happened. The gear cable moved immediately but the throttle not (though is was gripped).

I'll let you know!
Thanks again

se7en
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Re: 50hp Mercury - throttle setting

Post by se7en »

You need a time difference between the gear cable moving and throttle cable starting to move, if it didn't, it would damage the gear box, also the boat would be very difficult to drive when maneuvering .

alexARC
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Re: 50hp Mercury - throttle setting

Post by alexARC »

One more question (well 4 ...),
How do you choke (engage/disengage the solenoïd)? Any tips to control that the choke is working fine before to start?

What is your advise to start the engine (it hasn't started for a while, 1 year I think).

And also, where is the lever to unlock the engine in order to tilt it?

Thanks

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Rapier
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Re: 50hp Mercury - throttle setting

Post by Rapier »

Choke solenoid should work off the remote controller, either as a rubber push button on top of the control box, or if a later version, by depressing the ignition key as it is turned to the right. You should hear the solenoid engaging with a click (with the wrap and faceplate off..)

I'd remove the plugs, spray outboard inhibitor into the cylinders to lubricate and turn the motor over with the flywheel before starting it. The bottom plug will need to be removed with a suitable spanner, as access is limited.

To tilt, push the remote control lever forward past the neutral detent and in gear.

I'd always advise finding a proper factory issued manual and an operators manual before you work on it. They're cheap to download from the net and will save you trouble in the long run. Part number for my service manual is C-90-68647, it covers 1965 motors through to 1973, but later versions are available if you want a proper paper copy.
Fasten bra straps and remove dentures...

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