1960 lark 2 40 horse problems (updated w/pic)

[tmcalavy]

Re: 1960 lark 2 40 horse (update)

Re: 1960 lark 2 40 horse (update)

Should be an idle speed limiter on that motor somewhere. I think yours has the super quiet housing design, so it may be up near the throttle lever. On later models, they are back on the vertical throttle linkage. Might run some Sea Foam through it in some fuel and see if it settles down at idle. It won't run real smooth, when you find the right idle spot however.

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

I've got it just about fixed now. New Needle and seat in the carb, removed welsh plug, and blew out passages with carb cleaner again, and inserted a wire in every hole. Carb was clean but I did it anyway. Made up a new carb to manifold gasket as well, and changed both lines out on the tank/engine. It will run at low speeds now! Still seems to spit a bit when cold at low speed, but I havn't tuned the carb at all so once I can get it out on the water and start dialing it in, I should be good to go!

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

Great work!

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

Ok I dragged it out to a local lake yesterday. Got all the way there and saw a newly printed sign that said 25hp max. I figured as long as we weren't tear assing up and down we wouldnt draw to much attention It's all tuned up now and running great! Only took about 5-10 minutes to get it dialed in. The only problem with it is when the idle is low it will back fire and pop itself out. I had to bump up the idle to a point where it would keep itself running the smoothest possible. It doesn't sound high, and in gear it will just barely move so I think its about right. With the throttle all the way back though its just below the start position, not all the way back to the "low setting" on the indicator lever. Sound about right?

 

[coolguy147]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

enrichen the low speed neelde a little

 

[tmcalavy]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

Can't remember the "book" idle speed rpm, but remember that those throttle linkages/markings get sloppy over the years. If it idles down nice and shifts where you have it set now, I'd leave it there. Just remember to make a crisp shift when you put it in either gear...don't ease it into gear, that causes clutch dog wear...snap it into gear with one quick movement.

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

One Thing I wish it had is a tach. I'd be curious to know the RPM's at full throttle and Idle. With a dual points system though, it seems like it would be kind of a ***** to install one.

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

OK well I loaded my parents in the thing tonite to take them for a cruise and it started up great, and was running good. I took it up to about 3/4 throttle for a few seconds and my moms hat came off so I pulled the power back and circled around to get it, then brought it back to full and the bottom cylinder quit again! Worked fine last week when I had it out. I'm getting tired of dropping that cylinder randomly. When I got it home I checked both plugs and sure enough good hot spark on the top, nothing on the bottom. Tried disconnecting the over-speed switch to see if that failed, and still nothing. I'll pull the flywheel tomorrow to inspect, but anyone else have a similar problem?

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

You previously reported that you "re-terminated both ends of the plug wires". Did you install new spark plug boots or reuse the old ones? Try running the motor in a barrel after dark and see if the high voltage is visibly leaking to ground somewhere. Could be as simple as that. Good luck!

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated)

Re: 1960 lark 2 40 horse problems (updated)

Perhaps this has something to do with my problem? Found this ground wire just laying under the mag plate. Is it supposed to attach to the mag plate somewhere to ground the system?

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated w/pic)

Trace the wire to the other end and tell us what you find.

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated w/pic)

It's a ground wire. It's bolted to the block right below the mag plate

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated w/pic)

Turns out the rivet holding the points contact was loose, which allowed the assembly to rotate just enough to ground out. Points would open and close fine, but it was alwasy grounded so there was no spark. I was able to rotate it back into position and clamp the rivet down tight. Should be good to go! Did replace the plug wires and shrink wrap all connections to make them water/moisture proof as well.

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated w/pic)

Attaboy! That's a first for me. Were these new points? If so, what brand?

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated w/pic)

Not sure of the brand, they're copper versus the silver ones I took out.

Took it out today and it ran great! Then on my way back to the launch, running at about 3/4 throttle, the bottom cylinder cut out for about 1 min, then kicked in again. Then it would intermittently cut out and in for a while and then run great again.

Then the real problem happened. Apparently this propeller has a rubber coated shaft on the inside, and the drive shaft started spinning inside the prop, liquifying the rubber, and leaving me stranded. Are they all like that? Seems like a dumb design to me!

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated w/pic)

Bummer on the cylinder! Thought you found/fixed the problem. Since you are so good at removing the flywheel now, you might want to swap the coils and see if the problem migrates to the top cylinder or stays put. That will tell you a bunch about the source of the problem.

Regarding the prop, the rubber hub is the intentional weak link in the drive system. Keeps you from tearing up really expensive stuff if you hit something solid. Unfortunately, the rubber deteriorates with age and will slip under load. A good prop shop can repair your prop by replacing the rubber hub.

Hang in there!

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated w/pic)

If the prop hub is made to be a weak link, what good is the shear pin? I'd rather have that go then the prop hub. Seems like a solid hubbed prop and a weak shear pin would be a lot easier. At least that I could change on the water quick!

I'll have to run by the local repair shop and see if they do props, or who they take their stuff too.

 

[Les Robb]

Re: 1960 lark 2 40 horse problems (updated w/pic)

I don't know how old you are, but if more people now day's had your stick-to-it-ness our country would be a better place to live.

Best of luck in your efforts and don't get discouraged by the prop.

 

[bashr52]

Re: 1960 lark 2 40 horse problems (updated w/pic)

I don't know how old you are, but if more people now day's had your stick-to-it-ness our country would be a better place to live.

Best of luck in your efforts and don't get discouraged by the prop.

Thanks for the kind words. I'm 22 and it's a combination of being stubborn and not trusting anyone else to do my work, and being to poor to afford to take it some where. I've worked on just about everything (cars, boats, planes) so jumping into something new isn't that scary

Anyway the local Evinrude dealer said its $180 to buy a new prop, or $60 to have it re-hubbed. I'm going to swing in after work today and see what they think. I talked to the PO and turns out it is the original prop that came on that engine in 1960, so I'm sure the rubber was just waiting to fail. That and the fact it hasnt seen water in about 20 years as well

 

[Willyclay]

Re: 1960 lark 2 40 horse problems (updated w/pic)

The pin is a drive pin not intended to shear. It should be stainless steel unless someone has substituted an incorrect part. OMC referred to the rubber hub as a clutch. BTDT with those old props. Run for years and then one day just give up. You might find a cheap one on eBay but it will come with a question about how long the rubber clutch will last. Good luck!