1960 Evinrude Lark II surging

[Ksmith0110]

I picked up this 40 hp motor for a song and got it running with very little effort. I had it out Friday and it ran great. It pushed my old Alumacraft 15' to 22 mph according to the fish finder. So today I talked the wife and kids in to going to the lake for the 4th of July. Of course the motor would not run right. It started idling rough and when I'd open it up, the the rpm would surge. We made it back to the ramp and I loaded it up and headed home. I pulled the carb and found some gunk. I cleaned it out and ran it in a tank @ idle and it seemd good. I tried to open it up in gear and it revved up and blew all the water out of the tank...so I had to shut it down. I guess I need to get it in the lake again and try it. Is there anything else I should look at? I found some bad line near my connector @ the motor so I cut it off and hooked it back up.

Any suggestions?

 

[1946Zephyr]

Re: 1960 Evinrude Lark II surging

If you're finding gunk in the carb, that's most likely your problem. A dirty fuel system. Check the coils out too, make sure they are in good condition. Make sure the points are gapped right.

 

[lindy46]

Re: 1960 Evinrude Lark II surging

Should push that boat faster than 22mph.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

I took it out today and got 25mph out of her. I crank on the throttle and it takes off good but then kind of flattens out for about 20 sec. and then the rpm starts climbing to it's max rpm and it seems to run great.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

I'm not sure if the lack of top end is because it's a tri-hull or not. Is there much difference?

 

[lindy46]

Re: 1960 Evinrude Lark II surging

I wouldn't think that would make much difference. I had the same motor on a 14' Glasspar (fiberglass) and it would do 32-33mph. I guess on a 15' boat 25-28mph would be about right. What notch do you have the motor tilted? I'd try putting it on the third notch out (4th notch being maximum tilt). Not sure what you mean by RPM surge. Is it revving up and seeming to slip so as not to achieve top speed? That could be a slipping prop hub. But I wouldn't expect it to go very fast at all with a spun hub, unless she's just starting to go bad.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

It was the rpm that was surging, the bow of the boat kept going up and down. It acted like it was running out of fuel, that's why I pulled the carb. Like I said, I found some stuff in the carb and did a good cleaning, put it back together, and it seems to work good now. It picked up a couple of mph. I haven't done anything with the tilt of the motor.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

This motor is a '60 or '61, and I need the part number for the floats in the carb. It looks like the float is starting to come apart, that's where all the crap is coming from in the bowl. The float is probably the original one, it's cork with a shellac coating on it that is starting to flake off. Can anyone help me with a part number?

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

I replaced all the fuel lines today. It looked like the fuel lines were made from vacuum line! I got her fired up and it sounds good.
I posted a video on youtube of it:
http://www.youtube.com/watch?v=hQDojiouyjo

Theres a leak from the water pump to the gearcase and I've already replaced the seal under the water pump, but it is still leaking. Should there be sealant between the stainless steel plate under the impeller and the gearcase beneath it?

 

[lindy46]

Re: 1960 Evinrude Lark II surging

If you're talking about the water/oil dripping from the small hole on the side of the lower unit, that is normal. It drains water and exhaust residue from the case/lower unit. The area that is draining is not connected to the gearcase where the gear oil is. Keep that hole cleaned out - it prevents water from being trapped and freezing during winter storage.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

You say that's normal? The guy at the marina told me the seal needed replaced. I did and it's no better. Where is the oil coming from? Is it condensating from the exhaust - gas and oil mix seperating?

 

[lindy46]

Re: 1960 Evinrude Lark II surging

A lot of the oil you mix with the gas does not get burned during ignition. Some of the exhaust residue runs down the inside of the leg, where there is also water, as that housing is not sealed. That little hole is designed to drain all that junk out of the leg. You may also see exhaust/oil residue draining from the exhaust relief port on the back of the leg. If you run the motor in a drum of water, you will be shocked at all the residue in the water. The residue you see will have a gas smell to it. To see if your seals are leaking in the lower unit, just run the motor in a lake for awhile. Then drain a little gear oil from the lower unit. If water comes out, or the oil is milky, then you still have a leak somewhere.

 

[Ksmith0110]

Re: 1960 Evinrude Lark II surging

I checked the oil after my first outing and as soon as I cracked the oil plug loose there was a puff (like there was pressure in the gearcase) and I didn't see any milky oil.

 

[lindy46]

Re: 1960 Evinrude Lark II surging

Sounds ok then. Sometimes after changing L/U oil, if the oil is full right up to the top, you'll get a little pressure buildup. I usually let a little drain out to avoid that. Give her a little headroom. The fact that it's building some pressure indicates you probably don't have any leaks.

 

[loucks.walter]

Re: 1960 Evinrude Lark II surging

Hello Im new here I just bought a lone star with a Evinrude lark II and I have no Idea what year it is . can any one help. Also where i can get more infirmation

 

[kbait]

Re: 1960 Evinrude Lark II surging

Start a new thread and post the model number