'58 Mercury Mark 10 Mix?

[Dougan]

Title says it all... I just got my hands on an old '58 (Older than my dad!) Mercury Mark 10 motor. I wouldn't know where to begin at guessing how much to mix my gas. All I can find on google is things about using 10W30. But I should be using TCW3 or TCW2 now, right? I'm kind of new at this stuff. Any advice as far as what/how much to mix would be much appreciated!

Scott

 

[emckelvy]

Re: '58 Mercury Mark 10 Mix?

Use TCW3 outboard oil. Wally's will have what you need for this motor.

Use regular unleaded, if you can get non-gasohol use it.

50:1 should be OK for this motor as it is "fully jeweled", but in deference to its age you might want to mix the oil a bit heavier at, say 40:1.

Make sure she pumps water if you do get 'er lit off. Don't let it get so hot you can't put your hand on the block. Shut it off before it gets to that temp.

If you have trouble starting, you might check the Main Forum's postings on going through and outboard that's been sitting for a long time.

HTH........ed

 

[Dougan]

Re: '58 Mercury Mark 10 Mix?

Thanks for the help. I was able to get it started when I bought the thing. Took three pulls. However we didn't let it run for long because the water intake was in an awkward location and all we had was a hose, and I figured that wouldn't be enough water to keep it cool. Hopefully it is actually pumping water. I have another motor but I really wanna run this antique!

Scott

 

[ThumbPkr]

Re: '58 Mercury Mark 10 Mix?

I have a couple of those old mercs which still run but have not used them for years,a Mark 25 and a Mark 20 and it seems like I was running 20:1 or 25:1 which was the recommended mixture at that time based on the oil that was available back then.
I would be cautious about running too lean until you are comfortable with your performance and then experiment with the mixture based on your observations.
It is possible that prevailing wisdom has changed over the years but those old outboards are precious to me and I certainly would not want to lose one due to insufficient lubrication.Ron G

 

[Laddies]

Re: '58 Mercury Mark 10 Mix?

That engine is a 25 to 1 engine to run it on less oil is not a good call.

 

[emckelvy]

Re: '58 Mercury Mark 10 Mix?

Many years ago I ran my stock MK25 powerhead on a Quickie lower and a 9.5' runabout (just for pleasure, not racing) with TCW2 oil (all they had at the time) and 50:1 regular unleaded. Never a problem. I've always run my old Mercs at 50:1 with no issues at all.

And I quote:

" Q. What is the proper fuel to oil ratio for my old outboard?

A. The currently preferred fuel is the mid grade (89 octane). All post World War II non-racing Mercs (except KB-4's) can operate safely on a 50 to 1 fuel/oil mixture using modern TCW 3 oil. Racing models and the KB-4's should not be run leaner than 25 to 1. "

http://www.oldmercs.com/faq.html#ratio

So if you would, please explain what the difference is in the construction of a MK10, for example, that "requires" the use of 25:1 oil mix when compared to a motor with essentially similar features, an early-60's "Merc 200" with the automatic transmission, which can be "safely" run at 50:1.

Or, a 1958 44 c.i. MK58 and a 1963 Merc 500, which have virtually identical internals.

Or a MK78 and a Merc 700-6 Dockbusters. Had both of them too.

Now, I'm not trying to start some raging argument on this topic but it's one of my pet peeves and you guys brought it up!

Just my $.02 and apparently OldMercs too!............ed

 

[Laddies]

Re: '58 Mercury Mark 10 Mix?

Ed, those are your engines run the 100 to 1 if you like, I don't really care but if Mercury Marine has ever said you can run them 50 to 1 show me. The difference in the engines you mentioned is not in the design and manufacture it is in bearing tolerance and metallurgy. As far as Mercurys racing engines running on 50 to 1, we have raced, not played with them for many years and won 5 national championships along the way, ran KG-4s and Mark 15 in A stock, ran 30Hs in C stock, 55 H and 44XS in D stock so I know a little about the older engines. I have a friend thats a synthetic oil nut and is sponcered by one of the major manufacturers of synthetic oils he tried to run his 55H at 50 to 1 and could not keep top main bearings in it. So run your own stuff on any mix or oil you want but you should not give advice that goes against factory specs. Most of your threads I would agree with but I can't this one.
Bob

 

[emckelvy]

Re: '58 Mercury Mark 10 Mix?

OK, you're entitled to your opinions also.

But let me make this perfectly clear:

1) I never advocated running ANY engine on 100-1 which, #1, is absolutely INSANE and NEVER recommended by anyone, and #2, was an entirely uncalled-for and unprofessional remark. I thought we were trying to have some semblance of a rational discussion here, not descend into the 'depths'.

2) I NEVER made a statement in my post alluding to running RACING engines on 50:1.

If you'll read the quote from OldMercs, it says "non-racing Mercs".

OK, at this point we'll agree to disagree and that's all I got to say about that.

 

[Laddies]

Re: '58 Mercury Mark 10 Mix?

OK, and I will apologize for the offending 100 to 1 remark. Bob

 

[emckelvy]

Re: '58 Mercury Mark 10 Mix?

OK, Peace, Bro! Let's Hug!

Actually I should take back part of the Insane, 'cause OMC was crazy enough to run some of their smaller motors 100:1 for quite a few years but I guess history has proven them to be a bit optimistic in the real world, doesn't leave much oil residue on the bearings for long-term storage rust protection!

Cheers.........ed

 

[emckelvy]

Re: '58 Mercury Mark 10 Mix?

Followup: check this thread for words from Mercury Bulletin on Fuel/Oil Mixture Ratio for Older Merc Outboards:

http://forums.iboats.com/showthread.php?t=263882

 

[merkinstine]

Re: '58 Mercury Mark 10 Mix?

Thanks for the help. I was able to get it started when I bought the thing. Took three pulls. However we didn't let it run for long because the water intake was in an awkward location and all we had was a hose, and I figured that wouldn't be enough water to keep it cool. Hopefully it is actually pumping water. I have another motor but I really wanna run this antique!

Scott

Re: '58 Mercury Mark 10 Mix?

OK, you're entitled to your opinions also.

But let me make this perfectly clear:

1) I never advocated running ANY engine on 100-1 which, #1, is absolutely INSANE and NEVER recommended by anyone, and #2, was an entirely uncalled-for and unprofessional remark. I thought we were trying to have some semblance of a rational discussion here, not descend into the 'depths'.

2) I NEVER made a statement in my post alluding to running RACING engines on 50:1.

If you'll read the quote from OldMercs, it says "non-racing Mercs".

OK, at this point we'll agree to disagree and that's all I got to say about that.

Hello, I have a mark 58 thunderbolt that is not getting fire to the plugs, any suggestions? I have a thread going if you wouldn't mind joining in?

MOD EDIT: Please review the rules about posting to old threads.