Started on the Lark

[Cadillac-ack-ack]

Just got going on my '62 Lark rebuild. In the take-apart mode still and as this is a winter project not a rush. Pretty experienced with 4 stroke auto and bike engines and a little with 2 stroke yard stuff like small chain saws, weed eaters etc. Always thought 2 strokes were pretty simple and yes they may have fewer parts overall but I'm discovering this old Evinrude is a pretty sophisticated piece even at 55yrs old. Finding a lot of note taking is a good idea as it seems there is an order in what one takes off (carb doesn't come off unless starter is off and that doesn't want to slip over it's studs until the recoil is off). This, I imagine can be frustrating come re-assembly time if one goes out of order. The only real diagnosis I've come to is a bit of scoring on the exhaust side of both cylinders, more on the bottom hole than on the top. Measuring with a bore gauge, though, showed no out of spec taper or localized wear even in the vicinity of the scoring itself, at least as far down as the ports. Experience with cylinder scoring in the past leads me to believe the aluminum pistons probably took a much bigger hit. They are not out yet. Looking for oversize was futile but I did manage to find two NOS standard pistons on ebay and two sets of standard rings. I feel a minimum honing of the cylinders together with new pistons and rings will be just the ticket even though all the score marks will not be gone. I really see no other alternative other than a search for a new block and I really don't want to go down that route. - Pete

 

[Joe Reeves]

Future reference: Stud problem = double nut the studs and remove them, the start'll fall off.

Unless the scoring is really bad, usually deglazing the cylinders to obtain a crosshatch, cleaning up the ring grooves (new ring sets) and a light go around on the pistons with 400/600 wet/dry w/mineral spirits will bring them in line. However they'll probably fail somewhat in another 40 or 50 years again. Those engines were built like the ole Henry Ford Model A's.

 

[Cadillac-ack-ack]

That's what I was thinking and having new piston can only help.

 

[F_R]

Concerning the studs: I don't think I've ever removed them just to get the starter off. No biggie deal to remove the recoil. (and flywheel too, especially if doing a tune-up or major powerhead work). And getting the recoil, flywheel, and electric starter out of the way sure makes it easier to get the carburetor off. You get used to the routine eventually.

 

[Cadillac-ack-ack]

Concerning the studs: I don't think I've ever removed them just to get the starter off. No biggie deal to remove the recoil. (and flywheel too, especially if doing a tune-up or major powerhead work). And getting the recoil, flywheel, and electric starter out of the way sure makes it easier to get the carburetor off. You get used to the routine eventually.

All very very true. I'm finding that a logical order of things is a must. Also that these motors are amazingly compact. With the electric starter, for example, I found that with all the nuts and bolts off, its drive was just a whisper from clearing the recoil starter leg. Taking that off first was not a big deal. My procedure now is to list what comes off in order, so re- assembly in the reverse order should be smooth.

 

[boobie]

Edit...........

 

[oldboat1]

Don't bust it up, particularly if a family history to the rig. With a little searching, should be able to come up with a service manual -- parts manual sometimes more easily available.

 

[Cadillac-ack-ack]

Don't bust it up, particularly if a family history to the rig. With a little searching, should be able to come up with a service manual -- parts manual sometimes more easily available.

No sir, it's important to me that she runs well with as many original parts as are serviceable. I'm looking for a dependable rig that at the boat ramp I can proudly tell those that ask about her, her past as the family boat, and take pride in doing the job myself. I'm not going to take short cuts but at the same time I'm not going to throw money and new parts at it for the sake of new. I feel I've got enough experience with vintage cars and bikes to certainly help with the correct path to overhaul. I'm currently working from a Seldoc, apparently by Chilton for 1956 - 1970 Enirude/Johnson motors. Though it covers a range of HP's, so far it has been fine. I don't get frustrated when a description or procedure is not quite "as advertised. Patients and hand tools are your friend. Is there another manual out there that may be more specific to the Lark MK 4?

 

[oldboat1]

Well, close: https://www.ebay.com/itm/Ken-Cook-C...ash=item1ebf825f1f:g:6JkAAOSw44BYdw9j&vxp=mtr Ken Cook Co. avail here on iBoats.

 

[racerone]

Is this motor electric shift ?

 

[Cadillac-ack-ack]

Is this motor electric shift ?

Yes it is. Worked fine last time out 17 yr's ago. Can't go bad just sitting, can it?

 

[jimmbo]

Well wire insulation seems to go bad just sitting, ozone I think does that. What condition was the gear oil? The push button shift switch is not cheap if it fails
I think your engine still had an adjustable Hi Speed mixture, if not, then it was the first year for the fixed jet.
Some say the hot water choke is a problem with that engine, my dads 63 40 never had an issue.

 

[oldboat1]

Yeah, I've used the hot water choke on a couple of 40s. Worked well, which is kind of good news and bad -- never had to work on one, so can't comment on repairs. A working t.stat is important with the system, as you would expect. I always thought it was a pretty elegant system.

If the motor was running well 17 years ago and was stored with some decent preparation, it shouldn't take much to put it back into service -- wouldn't think you would need to get into the power head, so surprised to see reference to piston work (may be more to the story). Change out the gear oil, and keep it fresh. Check wire condition all around, and clean electrical connections to bright and shiny. Good idea to change hoses -- look for cracking/deterioration. Use a carb kit if doing carb work -- thorough disassembly and cleaning (soak, poke and spray). Refer to a parts diagram.

Nice rig.

 

[racerone]

The electric shift is very, very good and reliable.-----After all these years you may have to " polarize ' the generatir / voltage regulator.----No big deal when you get to starting it up again.

 

[Cadillac-ack-ack]

If the motor was running well 17 years ago and was stored with some decent preparation, it shouldn't take much to put it back into service -- wouldn't think you would need to get into the power head, so surprised to see reference to piston work (may be more to the story). Change out the gear oil, and keep it fresh. Check wire condition all around, and clean electrical connections to bright and shiny. Good idea to change hoses -- look for cracking/deterioration. Use a carb kit if doing carb work --
]

The only storage prep was that it was always inside. The first parts I got were, tune-up parts (points, condensers), fuel pump kit, carburetor kit, and head gasket. The kits were to assure dependable operation when it was time try it out next summer. The head gasket was because I thought there may be excessive carbon build-up because of it's heavy trolling use in later years, It never felt really liked going that slow for hours at a time. Taking the head off revealed some cylinder scoring and although the bores measured up as within tolerance I felt the alloy pistons will prove to be smeared and the lands damaged. They are not out yet but research showed availability of new ones is just about nil so when, after lots of searching, I found two NOS I jumped on them. I think with a light hone and new rings, even though I will not attempt to get rid of all the scratches, the cylinders will freshen up nicely. Don't know what lead to the scoring in the first place or when in it's active life this happened. Maybe a wrong oil/gas mix? Doubtful it was overheating as the water pump has always worked and the cylinder jackets are totally - totally clear (even a bit of red paint still in evidence.

 

[jimmbo]

Well unless the cylinders walls are score/scuff free don't expect ideal compression. Pictures showing what you are looking at, and of the pistons would be very helpful. Wrong oil or mixture may have been the problem, that engine was speced for 24:1.(though it was later revised that 50:1 could be used if Evinrude/Johnson/OMC, later to be TCW oils, were used). Perhaps someone ran some 10w-30 through it. No 2 cylinder 2 stroke of that size 'really like' trolling for hours at a time, they tended to load up and needed the occasional speed up.

Did you do a compression test before you pulled the head?

A new pump impeller is definitely one of the needed parts

 

[Cadillac-ack-ack]

I don't have any expectations that the slight scoring won't matter at all. I am hoping any compression loss is minor though and for all practical purposes won't be noticed. Funny you would mention oil ratio. I remember from my dim past my dad talking to the marina owner (and Evinrude dealer) about the change from 24:1 to 50:1. The marina started offering pre-mix at what I assume was correct for the motor but in my basement I also have three unopened quarts of Valvoline "outboard motor oil" for all 2 stroke motors including chain saws, mowers and motorbikes etc, and wherever a 30 or 40 wt non-detergent oil is recommended. Can shows a couple of happy boaters on the painted label a marching around the top is a line-up of all the equipment this oil was good for. I know we used this sometimes but not sure what mix was used. I think we just threw a quart in a six gallon tank. I did not do a compression test before taking the head off as I was not expecting any cylinder issues. It did pull pretty damn hard though. Still don't have piston out.

 

[racerone]

Save those old oil cans.----Worth some to a collecter I think.------Slight scoring is easily honed out.------Many good used parts for these motors are available if you know where to look.

 

[Willyclay]

Is there another manual out there that may be more specific to the Lark MK 4?

The link below will get you to the non-factory Clymer service manual for 1956-1963 Evinrude Big Twins and Larks. Long before the internet, I used this manual for my first outboard motor overhaul of a 1959 Johnson 35HP which is almost identical to your Lark. It served me well. Good luck with yours!

http://www.fiberglassics.com/library...service002.pdf

 

[Cadillac-ack-ack]

racerone, I do plan on keeping them. Actually think if it would be OK to feed it at some ratio to the Lark when it's back on the water.

Willyclay, Thanks so much for the service manual pages covering my motor. Got them copied and in a sleeve. Knowledge is power. Model number by the way is 35933 L. As I understand it, the "L" simply means a slight mid model change took place.