New to me Mark 10

[Tom Alexander]

Hi: Awhile back I was given a 1958 Mark 10. Today I took it to a very experienced friend to see if we could get it going. It had spark and symptom of fuel pump diaphragm failure but did fire. Replaced diaphragm and check valves and after a bit of fiddling we (he) got it running. It will start and run with the ‘lever’ in start position and die as soon as it is shifted toward run. We found that the grub screws (2 of them 180 deg. apart on the arm attached to the lever shaft) were loose. After removing the arm we found a hole drilled through the shaft and we assumed this hole was to accept    the 2 grub screws. We reassembled the pieces and got the screws tightened into the hole and found the lever hits the pan side way before the lever can even get close to the ‘troll’ position. Also, when the lever is pushed to the start position the linkages seem to push the timing cams etc counter clockwise (as viewed from above) and we think that would retard the timing in start mode. This seems opposite of what is needed. The engine does start though and run as long as the lever is not moved from the start position. Anybody have any thoughts?  Thanks. Tom

[billw]

Although I have about 30 automatics, I do not have a Mark 10 anymore. Their linkage is similar, but a bit different than, later, higher horse power models. I think they are close to a Mark 15A though, which I do have. I will take a picture tonight, if nobody is able to do it before then, so you can compare how yours is set up. You are right, though…the screws ARE meant to line up with, and go into the holes in the troll lever shaft. One question…if something is backwards, it would seem to me that you would speed the engine up by moving the lever towards troll, not slow down and die. All automatics, and the Mark 10 in particular, are capable of idling very slowly and smoothly. However, it takes a well tuned engine to do it. The carb has to be perfect, the ignition has to be perfect, the compression has to be good and the link and synch has got to be good. If it has the original condensers, those are almost certainly not up to spec. You might even be running on only one cylinder. 105 or so PSI is commonly good compression.

But the BIG question…..is that thing actually pumping water?????? Wow!

Long live American manufacturing!

[Tom Alexander]

Hi billw: YES it is pumping water! That is a good thing right now but the impeller will have to be changed before putting it on a boat and leaving shore. I did the first bit of reading about this little beastie last night and am amazed at the complexity of the job that is impeller changing on this motor! Surely they could have made it more involved. Sorry, getting a bit cynical there. My only other experience in the outboard world of changing impellers is on a 1959 Johnson 35 HP. It was done during a complete rebuild of the lower unit after I received the Johnson motor as part of a package deal. That ‘package’ by the way is finished and the family spent a couple of weeks on various Sierra lakes last summer. Couldn’t be more pleased. This Mark 10 will be fun if I can get the time and find the parts. The tools won’t be an issue, I have a pretty complete shop and can fab up just about anything, but not impellers! Where do you get stuff for this. On the Johnson rebuild I used  Marine Engine pretty exclusively. Very expensive from what my friends tell me, but they had all the parts I needed and, good exploded diagrams to boot. I went back to them looking to see what is available from them and I can’t even make out the diagrams and most parts are ‘unavailable’. I do have a manual coming. But as we all know about manuals, some are way better than others. I got a few pics taken today of the area under and to the port side of the carb showing that lever etc. I see that the grubs have ‘slipped’ and they are no longer entering the hole drilled in the shaft. We scribed the top of the shaft to help with alignment but apparently did not get it right as the joint was slipping today when I tried it and the grub screws are about 30 degrees off! I will try to post a pic or two if I can figure out a way to reduce the file size necessary to post. Thanks very much for your reply btw, you guys in this club have a wealth of knowledge and it’s great you take the time to pass it on.

[Tom Alexander]

Here is first attempt at file size reduction to 2.44 megs

[Tom Alexander]

Hi : Yesterday I had a few minutes to try to get this troll lever aligned with the troll lever arm. It turns out it is not possible to use the hole drilled thru the troll lever to tighten the set screws on the troll lever into. To do that requires the the arm to contact the ‘pan’ and restrict rotation from full ‘start’ (way past the detent) to midway toward ‘run’. Using the detents on the unit that fits into the throttle control bracket (I cannot make out the part on my copy of a Mark 10 Parts list with exploded diagrams Revised Jan 1960) I determined that the range of ‘throw of the Troll Lever is really only between the ‘S’ of the word Start and about the last ‘L’ of the word Troll on the indicating/instruction plate. In the picture of my ‘resolution to the problem’ the scribed mark on  the top of the shaft aligns with the hole drilled in the shaft. As you can see I had to tighten the set screws onto the bare shaft (missing the hole by far) of the lever to achieve the throw on the lever to achieve all three (Start, Run and Troll) settings with ‘Run’ somewhere in the middle of throw and ‘Troll’ and “Start’ on either side. Using the detent to  ‘feel’ for the setting needed will be the course of action during operation I believe. If someone knows anything more or can advise if what  I have is a bastard fix or part replacement someone has done in the past please let me know. Also If anyone knows where I can get a service manual of this Mercury Mark 10 S.N. 1120389 I would certainly appreciate it. I did download a copy of a Parts Manual that was mentioned in a thread on water pump impeller replacement and am curious if this is the best quality copy around. Many of the smaller parts pictures and unclear but so far it has been a great help in describing parts.   Thanks All!    Tom Alexander

[Tom Alexander]

Today I got better pics of the only assembly configuration I could get to work on the Troll Lever to Troll Lever Arm. Turns out just a small displacement left to right takes you from Troll to Start.  Hopefully the picture titles come thru with the pics! I think the order that show in is, Run, Start and Troll. Thanks  Tom

 

[billw]

My memory didn’t serve me well. My Mark 15As’ throttle systems are nothing like the Mark 10, after all. Not even worth taking a picture of. I wish somebody here with a Mark 10 would post a picture, to compare to yours. Usually, in run position, the warm up lever is more or less in the center. On yours, it looks like that it’s not quite to center, even in the start position. I don’t get it; but if it’s working, great. There is no specific manual for a Mark 10. What you want is the general Mercury service manual for models 1965 and prior. It covers many of the models we club member find most interesting. The manual will not be very specific with regard to the troll lever issue but is pretty good when it comes to doing the water pump.

https://www.ebay.com/itm/374487848877?hash=item57313717ad:g:g9AAAOSwZBBj2Bwq&amdata=enc%3AAQAHAAAA8A%2FxFmnlPoHfv6BAkZDIWjsYbYB3%2BBMw6DNLbuW8gBXMizlbbOvismgyCXQlvoLTBV%2F%2FaaqNsuVwnFNqpC%2FNm2pgPQacvhIuvHEhuoNFVCcZxEprXUzkGlI0xOigLVr7TGMysAQRahKaYf84LI2qXIQX1Bll45SwU5AWNCwbZApgTN2lb9QDD1IEjGaEPhpprTFQmRo0jAawHI%2B3C0XfZmkpKyUPUCvaGArDHq3zk%2BELLJH%2B8skqp3tRDUpuzgRyCZ9E5%2BQjkfxSzYSQJ7F%2FGvQWfm5wbn4X%2Fjl322D%2F%2BgvU95sFeSoXdcHN2ep%2FA3IlWQ%3D%3D%7Ctkp%3ABFBMrOjXpuRh

Long live American manufacturing!

[Tom Alexander]

bills: thanks for the reply:  last nite I dug around some and found that on my engine the set screws are square with the arm and on others I saw the screws were oblique at quite a angle. I think that is what allowed them to get into the hole (sort of two holes as the screws enter from both sides, if that makes sense) and keep it from slipping. Makes me wonder if one of the other arms would work on this engine as that is certainly a better method of securing the arm against slipping. My photos show the lever in the 3 position as dictated by the detents and not any random positioning by myself. Thanks for the heads up about there being no ‘real manual’ for this engine. I was thinking myself an inept searcher after the hours wasted trying to find one! I did uncover other interesting mercury info though.  Thanks Again  Regards  Tom Alexander

[billw]

Just to be clear, there is no manual JUST for a Mark 10, but the eBay link I posted shows the official Mercury Marne manual for many vintage engines, INCLUDING the Mark 10. All in all, it is a very good manual and the bible of old Merc guys. It is not always step-by-step for everything; but still, it is pretty much indispensable.

Long live American manufacturing!

[seakaye12]

Parts Manual.  Maybe better than what you have or maybe not.  Too big to post here but I can e-mail it to you if you would like.  Just PM me your e-mail address.

 

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