TOPIC: I need a picture of a Mark 55's 6 gallon gas tank

I'm hoping that someone has an original vintage 6 gallon gas tank or at least a picture of the tank that would be the correct match for a 1955-56 Mark 55.
My concern is whether or not it would have a large rectangular cast aluminum area with a handle that is fastened to the top center area of the tank with a bunch of machine screws - somewhat like the earlier Mark 20 pressure tank - OR - if the 6 gallon tank is similar to the '60's tanks that just have the female fuel fitting in a 2"x 3" (+/-) cast aluminum piece secured with (4) machine screws and a 1/2 twist filler cap.
Thanks,
Thom

either or. they used the pressure tanks modifyed to pump till they ran out so eithr or.

So-o-o-o,...If I have one of the pressurized tanks, but have the primer disabled - I can put a prime bulb on it and use it with a fuel pump system???
How would I vent the tank?
Thanks,
Thom

Here you go Thom. These are what I assume is the original 6 gallon tank(plus a period larger cruiser tank) that I found in the all original mahogany ply boat with its Mark 55e hanging off the back. And btw they are not pressure tanks...my Mark has a fuel pump.

they were modifyed by merc at the factory thr brass knob on the handle was the vent.

Barnfinder,
That is exactly what I need to see.
Can you snap a couple pictures of the top area and the decals - if there are any others besides the one large one on the side.
Thanks!
This is very helpful!!!
Thom

You got it Thom,

I actually have another Merc tank that I believe is a little newer vintage. I brought them both out and even gave them a bath to look pretty for the camera. Both tanks have only the one emblem on one side btw

One on right is the one I got with the orphan wooden boat and Mark 55. One on left is just another I picked up and is probably newer.
(sorry about the blurry pic)









Pretty cool design. Click on that pick to blow it up and see the aluminum post sticking down below the left side of the handle. You slide that back to open it up(next picture). The brass vent is on top of course but as mentioned by Dave , it appears these tanks were originally pressure and modified at factory...notice the little lift plunger on the right hand side under the handle to pump pressure and embosed on the tank beside the fuel connecter it says air where the second line would have connected.



If you ever make it over to the Rochester area Thom I'd let you have the second tank if you need one.

Good luck,
Tim

Tim,
That is exactly what I needed to see!
Thank you very much for taking the time to snap the pictures for me.

Can you explain to me how the vent system works?
I assume you would turn the knurled brass knob and in doing so those parts on the underside of the 'cap' must back down their threads and in doing so opens a vent hole??

If anyone has one of these tanks that is clean inside and has this factory modification for use with the early fuel pump Mercs I am interested in purchasing it, or just the center of the handle with the vent assembly if the tank is no good.

Please write direct if someone has such a tank for sale.
frankenmerc at comcast dot net

Thanks again Tim!
Thom

yes the knob opens vent holes.

Thom,

You are most welcome. It was actually a good thing that I pulled it out of the basement and cleaned it up and also noticed that the little bit of fuel left in it was down to some serious varnish and I see some rust. Off to get some Mollasis tomorrow to start the two week or so soak process to clean her up inside(works great..Google it for removing rust btw)

Looks like your tank is the exact same before the factory mods to convert to single line with fuel pump....including the unknown yellow strip that had who knows what on it originally.
I will have another look at the tank tomorrow and try to get some pics specific to the vent.

I think you are correct that you could convert yours with an different set of handles(and you would have to plug off the air hole also). You could maybe modify that air hole to be a vent somehow I suppose and just use the fuel line port.

Just a thought. Now if you could possibly please tell me why the 82 Merc 50 I am working restoring that will not return to idle after Goosing it on the hose manually with throttle arm.(see my other post). I have it running nice but for that and looking good.(see below)

Thanks,
Tim

Got your throttle cable adjusted correctly???

Thanks Dave but this is happening without the cable attached. I have the idle stop set good and then when I manually boost the throttle it does not return the RPM's to the idle I set and I have to quickly adjust the screw on the the throttle arm to reduce the revs then it comes dowm slowly and then way too low until I adjust it back up again.

Something to do with the timing perhaps? I did replace the trigger and other stuff.

Tim

check and see if the butterflys are sticking.

Good idea...will do. Thanks.

The following problems have the same symtoms on an inline-6 with the same style ignition but slightly different linkage and I don't have an assembled 4 cyl adi here to confirm these problems could also occur on the small 4 cyl adi,....BUT check and see if the wiring from the trigger is dragging on the endcap housing or block or is restricted from free movement as it travels between the trigger and switchbox due to the wires or their sheath being too stiff to properly change shape as needed to move properly. (if so - use a heat gun to soften the sheath or wires and reshape things to run free throughout the movement).
You should be able to reach in with your finger while the motor is turned off and manually advance the trigger and when you let go it should spring back to its 'idle' position.
Thom

The following problems have the same symtoms on an inline-6 with the same style ignition but slightly different linkage and I don't have an assembled 4 cyl adi here to confirm these problems could also occur on the small 4 cyl adi,....BUT check and see if the wiring from the trigger is dragging on the endcap housing or block or is restricted from free movement as it travels between the trigger and switchbox due to the wires or their sheath being too stiff to properly change shape as needed to move properly. (if so - use a heat gun to soften the sheath or wires and reshape things to run free throughout the movement).
You should be able to reach in with your finger while the motor is turned off and manually advance the trigger and when you let go it should spring back to its 'idle' position.
Thom

Thanks Thom,

I did think it might be the trigger harness hanging up so I cut the tie and made sure it was moving properly(reminds me I have to replace that....).

It seems to be ok now with cables hooked up but of course I cant really do much reving on the hose. I think it will be fine.

She's purring pretty good.

Check it out: =>