1959 Evinrude Lark 35 HP not revving

[Micky6]

Hi everyone,
Have my Lark 35 giving some strange problems !
Starts and idles fine.
Head out on lake, and boat gets to 10mph if I'm lucky.
Just doesn't seem to go like it used to ( 25mph in the good ol days.)
Motor was running from summer 2004 to end of summer 2006 ( overheated from weeds )
New head gasket now, so compression is fine at roughly 105 a side.
New plugs ( J6C ) and coils, recent wires, points and condenser ( 2004 )
Checked yesterday the top cylinder plug is oil wet ( not firing properly ? ), bottom is slighty wet edges, with dry center.
Oil / gas mixture might be a bit rich ( 3/4 quart to 5 gallons gas ).
Seems to me that the throttle lever on the remote control is not all the way down ( linkage ? )
Also have black wire hanging from under flywheel, with ring terminal on it ( I don't think I have a vacuum switch )
Any ideas ?
I love this old girl, don't want to give up on her !

 

[F_R]

Re: 1959 Evinrude Lark 35 HP not revving

It would appear that it is running on one cylinder. You can verify that by shorting one plug at a time to see if the result is the same. There are lots of one-cylinder causes, ignition, compression, water in cylinder, broken reed, etc, etc.

The wire goes to the vacuum switch, or where the switch should be. It is not causing your problem unless the ring terminal is touching a metal ground. That certainly would do it.

I suspect the overheating has something to do with it. Compression seems kind of low (?). Are you checking that with the electric starter or rope pull? If rope, is the compression relief disabled?

It's easy enough to tell if the control has anything to do with it---just look at the motor to see if the throttle (spark advance & carburetor) is going wide open

 

[Scurvy Knave]

Re: 1959 Evinrude Lark 35 HP not revving

If the vacuum terminal is shorting out to ground, it will prevent one of the cylinders from firing to prevent over-revving. Try wrapping the loose terminal end in electrical tape. Check the wire for any spot where the insulation may have been worn off.

If that doesn't do it, do a cylinder drop test to find the culprit. Go from there to eliminate potential causes. Good luck

 

[Micky6]

Re: 1959 Evinrude Lark 35 HP not revving

Thanks guys,
I had a local "boat guy" get the engine running for me ( after the overheat ).
I brought the motor to him.
He put the new head gasket on, and said it had good compression.
I think he said 105 a side.
He had it running just fine, and said to set the high speed needle. ( which I did 3/4 out )
He had taped up the end when I got it back 2 weeks ago.
Seemed all the "problems started when I hooked up all the remote control cables and wiring harness.
Had wrong starter switch, blew a coil, finally got all that sorted out. ( wiring diagram helped ! )
Starts now and idles fine.


I will check for spark again ( did it after all the wiring was redone w/ new coil, and had both plugs sparking )
I have a compression guage, and will check when warmed up.

I have the "Made in Germany" green coils, are they OK.
Also it's just a pig on gas, which is probably because of a dead cylinder !

I keep you guys posted,
Thanks

 

[Micky6]

Re: 1959 Evinrude Lark 35 HP not revving

Well,
Warmed it up, checked for spark ( with inline lighted wire tester )
Went to do the cylinder drop, and while grabbing the boot, got a little jolt !
Got spark in both, but the "light" seemed a little dimmer in the top cylinder ( which before was the most wet )
Checked for compression, got 130 in top cylinder, 128 in bottom.
Cleaned and re-gapped the plugs. ( .030 I'm guessing )
Took it out on lake, got up to 20mph ! but motor seemed to "jump" in stages all the way to the higher speed.
Plugs are both clean centers brownish, but with wet oil all around core !
Got to be a spark "thing".
What about wires ?
Seems to use a lot of gas, 1/4 tank ( 5 gallon) for my little jaunt around the lake !

 

[Micky6]

Re: 1959 Evinrude Lark 35 HP not revving

Well,
went out fishing,
and back to it's same ol tricks.
no power.
barely got to 10mph, with out planning like before.
This engine is driving me to drink, or boating me to booze !

 

[nineteensixtycaddy]

Did you ever come up with some kind of solution?

 

[nineteensixtycaddy]

2 yrs later... no answer

 

[GA_Boater]

2 yrs later... no answer

I wonder why? Could it be because he hasn't been here in three years. I hope you have been waiting two years for answer. :facepalm:

Closed