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TOPIC: New to me 1971 Evinrude Lark 50hp...

New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112202

Thursday I am buying a 1971 Evinrude Lark 50hp mounted to the back of a 65 MFG Niagara Custom. It is connected to a Selectric Remote system. I fired it up today when I looked at the boat and she started up just fine and ran both forward and reverse. Other than just a little grease here and there she was clean under the cowl. Mountings were secure and steering assembly was new and mint. I'll post some pictures Thursday/Friday.

I was wondering if any of you had experience with this motor/setup and if there were any big things to look out for, or to be aware of, before I put her in the water for her first cruise.

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Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112206

M-HeadMFG,

WELCOME ABOARD. - Someone here will KNOW, as this is where the REAL experts hang out.

yours, satx

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Resistance to tyrants is obedience to Almighty God.
Thomas Jefferson, 1803

Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112210

  • ed-mc
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The lower unit is actually a Hydro-electric (or "Hydromatic" if I recall correctly), has a pump to assist with shifting to Neutral and Reverse, and has (2) electric solenoids which move a "spool" back and forth to divert fluid for shifting operations.

The important thing is to keep the correct oil in it, either OMC Type "C" or its replacement, "Premium Lube". Must say on the jug of oil that it's rated for electric-shift lower units. Any water in the oil can cause sludge which will clog the pump screen and hinder shifting action. Most common leakage point is the driveshaft oil seal (under the pump).

Not a horrible setup by any means, but it does have its idiosyncrasies. Unlike the older Selectric models (spring-driven), this unit fails into Fwd. So, you'll at least get home under power if the electrical or pump fails! Unlke the old system, if a spring broke you were backing up to the ramp or rowing. I have fond memories of sitting on the bow of the '64 Glasspar Avalon when the V4 Evinrude broke its Fwd spring, while my Dad was backing the boat down the bay, back to the ramp!

There is also a convoluted set of diodes to prevent the motor from starting when you hit the key, until the pump is turning and develops enough oil pressure to pump the lower unit into Neutral.

All that is pretty complicated if you have to troubleshoot it, but if it's working, don't mess with it! It'll be fine.

The main thing I'd be concerned with is when was the last time the impeller was renewed. You'll have to deal with the electric shift cable if you drop the lower unit; be sure to pick up a factory service manual for that.

Or check out this online service manual, pretty cool!

www.boatinfo.no/lib/evinrude/manuals/1971-1989johnsonevinrude.html#/0

If it was a freshwater motor, there's likely a lot of life left in it. I'd recommend verifying or replacing the impeller, running some Seafoam carbon treatment in the fuel for at least a couple of tanks, and using non-ethanol fuel if you can find it. Either way, use marine fuel stabilizer in each tank and you'll cut way down on fuel system problems.

Mix fuel in the ratio of 50:1 using TCW-3 marine oil; Walmart carries quite a few brands and even their Super Tech oil is decent stuff. I recently picked up a pint of Merc Premium synthetic oil at Wally's for not much more than the inexpensive stuff.

Congrats on your "new" "hole in the wall" & have fun!......ed

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Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112403

Thanks Guys!
Here we go with pictures....

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Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112415

  • ed-mc
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Looks clean, have you tried it in the water yet??

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Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112446

Not yet, I have to finish getting her registered on Monday/Tuesday so I'll be launching her on Wednesday. I've drained all the gas out of the tank and replaced it with 93 octane with oil. Battery is on a float charger and everything else seems good to go.

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Re: New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112906

Ok... Ran her yesterday for about 3 hours.. I only went up to 3/4 throttle due to chop and traffic. She ran very well with no smoke and no funny noises. There were a few issues at low speed though...

I had a heck of a time getting her started at the dock. The Selectric control has a toggle switch for the choke. She would crank for 2 sec. and then spin out. Turned out I had to advance the throttle to 20% to get her to catch and then she fired right up. Every other start was easy but the throttle had to be at 10-20%.

She idled well but any lower than 10% throttle she would conk out. I am new to outboards but it feels and sounds like my throttle handle is not set up accurately to the engine. 25% throttle "sounds" like 10%. At 3/4 throttle I was going 25-27 mph. I did some practice emergency maneuvers and if I went from 25% forward throttle to 0 throttle and then hit neutral I had to immediately advance the throttle back up to 10-15% or risk stalling. I tried 20% forward throttle and then immediately dropped her in neutral but then she sounded like she was over revving. Any Ideas?

Finally, reverse was very unresponsive. I had to be at 50% or better to make any sternway at all. I think that is just a factor of my prop angle but I am not sure.

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Re:New to me 1971 Evinrude Lark 50hp... 9 years 4 months ago #112912

  • MarkS
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Much of the time these motors are put up with gas still in the carbs and fuel pump. After a while it gunks up the fuel system making the idle rough. As Ed suggested some Sea Foam or other gas treatment may help, or you may need to pull the carbs and fuel pump down and clean them out. Kits are very reasonably priced and they are fairly simple - not hard to rebuild at all. New fuel lines are also a great idea, as they usually break down inside before you even see a problem on the outside.

Once that's done the manual Ed gave you a link to shows how to do a "link and sync". It really means adjusting the throttle, spark, and shift linkages to give you optimum performance. These motors run like a smooth sewing machine at all RPM when you get them dialed in properly. Reverse never will give you much, it's as you say turning the prop the wrong way.

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Mark
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