1954 Mercury Mark 20

[Goodtimescowboy]

Ok guys, this is my first post, but I've visited alot lately. I aquired a Mark 20, and it runs and all, has a few sputters, and I am currently tuning up ignition system. ANy suggestions are welcome.

My post is for advise on the cooling system. The copper tube running from the impellar, which I am replacing to save a headache, should be solid right? The reason I ask is while having the lower unit off, I decided to flush the water side. It seems that no water actually reaches the block because no water came out the seep hole, but rushed back down thru the drive shaft housing where there are 6 or so small holes out the back for some exhaust to escape I think. I only ran the engine enough to see it ran, and when no water came out the seep hole, but sprayed out the back where the small holes were, I shut it off, satisfied it ran, but knowing there was work to be done. Now, back on subject. I pushed some water thru the copper tube, no water out seep hole, rushed back down inside of drive shaft housing. Puffed air up thru it with my mouth, nothing out seep hole, but could hear it inside the housing. DO I need to replace the tube, and if so how do I go about removing the part that the drive shaft runs in below engine? Please feel free to correct me on terms/ names of parts because I want to know. I am very mechanically inclined, and not afraid of the project.

The Engine cover and serial number plate both say Mark 20, but the Block has hurricane on it. ANy info on this? I have realised this is a good engine after doing some snooping online, parts seem readily available, but will this be a good river boat engine, and some times a kicker on my bigger boat? It's painted odd, and I plan on making it look original. Also, the tiller handle doesn't seem to be tight enough to run throttle itself, but the knock out plate is out on side where you can run a control, and the person I got it off of "engineered" a way to run throttle there. How can I tighten up the gears in the tiller to run it original? The handle turns when you flip the tiller back behind motor, and it turns when you run the throttle on the side, but slops when you try to run it from the tiller. Any help?

Thanks in advance..

 

[bktheking]

Re: 1954 Mercury Mark 20

I have the same motor but a 55. Would I use mine as a daily, not a chance. Would I use it a couple times a year to run it, for sure. Have you pulled the flywheel to have a look at the ignition to see what shape the coils and points are in? If you have the $$$ and want a motor that is reliable a full magneto rebuild is the way to go. The block is a hurricane block, so there's no mistake that's what they came with. You'll find a serial number stamped on the blocck which should correspond to the one on the clamps. If the #'s don't match then someone has replaced the block, if they do then you have a numbers matching motor. Also- Merc used to put a lead seal on the block, if it's there then the powerhead is factory original. These are a collector motor and that's it. There is no tell tale on this motor unless someone drilled one in the powerhead. When they run water mists out those holes in the midsection, that's all you should see. As far as the throttle control I don't have the answer but I can point you to a diagram.


http://pub9.bravenet.com/photocente...#bn-photocenter-1-1-737212788/49338/1/116165/

 

[Laddies]

Re: 1954 Mercury Mark 20

Look next to center nut on the port side of the drive shaft housing where it attaches to the engine, there should be a 1/16th" hole that goes straight up whats the telltale most Mark 20s have one but a few don't. They plug quite easily I ussally use a drill bit to clean then, don't use a electric drill just your fingers and a bit.

 

[bktheking]

Re: 1954 Mercury Mark 20

Mine hasn't got one so I guess it's a mixed bag.

 

[who10]

Re: 1954 Mercury Mark 20

I may be wrong here, but I have an old 1954 6hp Merc Wizard WG4. The water does not seep out of the copper tube as you've described. It's suppose to come out of the 6-8 holes in the leg as a mist. I've got a video of it running at the following link. http://www.youtube.com/watch?v=ZYzGBYCIfI0
This motor also exhausts out the bottom of the leg, underwater and above the prop.
I have more pics at this location.
http://hubpages.com/hub/Selecting-a-Used-Outboard-Motor

 

[Goodtimescowboy]

Re: 1954 Mercury Mark 20

BKTheKing and who10. Thank you very much for the replies. So the copper tube shouldnt leak, and if standing on back side of the engine starboard side there is a small hole, probally that 1/16 described. I will try to clean that out, and from what I can find that copper tube just pulls out of the water sleeve, and I can buy a copper line that diameter, bend as close as possible and reinstall. First I will clean the tell tale and see if water is produced. If what you are saying about the small holes on the midsection, it must just go to water sleeve and straight back down. I would hear my breath in the midsection then, and may have no problem at all. Ok, anyone have a described way of taking all cowls off along with top to get at fly wheel. I don't want to break anything/bolts. The tiller throttle problem I think is due to the grease is old where the timing adjusts with the throttle under the fly wheel. I am going to clean that all with the points and everything. What kind of grease do you think. Dialectric is what I was thinking. Any way to lube up all the throttle linkage? When running the throttle on the side it is a little tought going. not like I have to force it, but definate resistance. So I am thinking if I can get that smoothed out and nice and loose everything will work A-OK. Any advice with that idea gentleman?

 

[Goodtimescowboy]

Re: 1954 Mercury Mark 20

Thank you to Laddies

 

[bktheking]

Re: 1954 Mercury Mark 20

I use white grease to lube that stuff up , others may use something different.