Topic: 1959 Evinrude Lark 35 hp tear down – Page 3

This topic has 31 replies, 5 voices, and was last updated 4 years, 3 months ago by fleetwin.

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October 13, 2020 at 1:09 pm #218460
fleetwin
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US Member - 2 Years
OK, I get it I think…The pin was beating its way up and down on every stroke….
October 13, 2020 at 2:52 pm #218466
bobw
Participant
US Member
It is somewhat fortunate that the cylinder wall apparently escaped significant damage from the pin and ring pieces flying around in there.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
October 13, 2020 at 10:18 pm #218500
Buccaneer
Participant
US Member
I’ll try to get a better photo of the piston, but the pin dug a tunnel from the top ring
land and popped out on the top of the piston, where the big ugly hole is in the photo.
I did not see any evidence of the pin or pieces of the piston floating loose in the
cylinder. Guess they’re in the bottom of some lake!

I took the exhaust cover off today. The inner cover does not appear to have any
pin holes in it. Lots of oily coke / carbon in the exhaust chamber though.
Cleaned up the powerhead somewhat as well. Next I’ll clean up gasket surfaces
and try to hone the cylinder and do some measurements.

I may check the lower unit to make sure it’s “viable” before I go ordering pistons, etc.

Prepare to be boarded!
October 14, 2020 at 5:04 pm #218563
Buccaneer
Participant
US Member
I cleaned and honed the cylinders today about 10 strokes
with my three stone hone. I don’t have a ball hone big enough,
but assume the hone I used tells a better story of the cylinder
condition?

Anyway, the cylinder looked better before cleaning and honing.
The bad cylinder with about .012 out of round at the top,
and has about the same taper from top to bottom of the bore.

The grooves in the bore are deeper than what it looked like at first,
and I’m afraid it would be futile to hone them out given the measurements.
If I had some “cheap” used pistons I’d give it a try. Guess it would run,
but not sure how good, or for how long! I’d be hesitant to spend $200 on
new piston and rings in the shape it’s in.
That cylinder had 60 psi with the destroyed piston, so I’m sure anything
would be an improvement!

What are your thoughts?
(Scroll down a ways to see the cylinder photos)

Prepare to be boarded!
- This reply was modified 4 years, 3 months ago by Buccaneer.
- This reply was modified 4 years, 3 months ago by Buccaneer.
October 14, 2020 at 5:20 pm #218569
fleetwin
Participant
US Member - 2 Years
Oh well, guess it was just wishful thinking…I think I see the groove where the pin was rattling around though. Hard to believe the cylinder is out by .012″ though… Hopefully you can find some new style oversize pistons/rings…Will look…
October 14, 2020 at 5:55 pm #218570
fleetwin
Participant
US Member - 2 Years
Looks like marinengine.com has one .020 oversize piston in stock, they have oversize rings also…I guess you will probably have to get it bored first before you know if the .020 oversize will work..
I guess you would have to have marineengine look at the piston to see if it is the new style or not….Maybe it will come with the rings also…Give em a call….
October 14, 2020 at 6:41 pm #218572
frankr
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US MEMBER PAY BY CHECK
Lots of people would disagree, but I would have no qualms about just boring the one cylinder. I’ve done it many times, and danged if I could tell any difference with just one oversize.
October 14, 2020 at 6:53 pm #218573
bobw
Participant
US Member
Guess I was wrong in my original evaluation of cylinder damage. It didn’t look that bad before the hone job but something sure “machined” some grooves in there. The top cylinder measures out good and if it’s not scored, I would agree with Frank and just bore the bad cylinder and save the cost of an additional oversize piston and rings.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
October 14, 2020 at 7:38 pm #218574
Buccaneer
Participant
US Member
Thanks for your thoughts. It may be a problem finding a place anymore in the area that will
bore a small engine. Perhaps a motorcycle dealer?
The local Napa use to have a engine machine shop…… long gone.

Prepare to be boarded!
October 14, 2020 at 9:04 pm #218584
frankr
Participant
US MEMBER PAY BY CHECK
A general machine shop that has a Bridgeport mill??
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