1957 lark 35

[ddonuts]

I have a lark 35 that was running fine. It started chugging out and then just stopped. I replaced fuel tank, hose, fuel pump diaphram, filter. I have fuel going to carb. I pulled line off and turned key, fuel came out. I took carb off and opened , cleaned with carb cleaner. replaced o ring that seemed to be falling apart around stem. put back together, no change. I have spark. The motor will start for a few seconds if I spray starting fluid into carb, but then dies. I'm tending to think it has something to do with the electric cut out switch mounted on the block. no one around here even know what this is? could this be the problem?

 

[Upstatehunter]

Re: 1957 lark 35

Did you clean all the ports in the carb and blow them out?
Sounds like it is still clogged. Had the same problem with my 1960 40HP lark II. High speed jet was really clogged. Hardly move air through it. Low speed jet also. Needle was an old one with a rubber tip. Wasn't allowing enough fuel due to wear. Replaced float, needle and seat and cleaned the entire carb out. Took two times to clean the whole fuel system and carb. Now back to running fine.
Was told these old motors were almost aero space engineered(that time of US history) and if one little thing is off they won't run right.
May just be as simple as the float hanging up a little and not opening the needle valve.

 

[lindy46]

Re: 1957 lark 35

Has the motor been converted to use a fuel pump? It originally would have used a pressure tank and no fuel pump. How did you test spark? With a spark tester you need to jump at least a 1/4" gap. If the cut-out switch was malfunctioning, you wouldn't have spark to the bottom cylinder. How are the coils?

 

[ddonuts]

Re: 1957 lark 35

thanks. I'll take another look at it. See what happens

 

[ddonuts]

Re: 1957 lark 35

lindy46,

It has the fuel diaphram and filter on the left side of the block. no pump per say. I disconnected the fuel line at carb and placed in jar. when I turned motor over, fuel filled jar. I didnt use a spark tester, I pulled the top plug out and turned motor over, I could see spark and my buddy got zapped. I'm new to this. 1st boat. I'm thinking if the coils were bad, I wouldnt get any spark? Am I missing something?

 

[lindy46]

Re: 1957 lark 35

If you have good spark and compression, and fuel is getting to the carb, then there is some crud somewhere in the carb keeping it from running properly. Could be old fuel lines contaminating the system. I'd replace the lines, make sure the tank is CLEAN and clean the carb again.

 

[F_R]

Re: 1957 lark 35

You have not tested the spark, you just think you have. You can stick your finger in a light socket and it will knock you out of your drawers, but that won't run a motor.

You need to check your compression to make sure you haven't blown a head gasket, then if that is ok, check the ignition properly.

It is NOT the vacuum cut-out switch.

And, most likely it is NOT a fuel problem.

 

[ryendube]

Re: 1957 lark 35

I have a lark 35 that was running fine. It started chugging out and then just stopped. I replaced fuel tank, hose, fuel pump diaphram, filter. I have fuel going to carb. I pulled line off and turned key, fuel came out. I took carb off and opened , cleaned with carb cleaner. replaced o ring that seemed to be falling apart around stem. put back together, no change. I have spark. The motor will start for a few seconds if I spray starting fluid into carb, but then dies. I'm tending to think it has something to do with the electric cut out switch mounted on the block. no one around here even know what this is? could this be the problem?

chugging out? did it sound like it was flooding or starving ? was carb full of fuel when you dissassembled? are you still using an original style cork float?

Obviously F_R knows what hes saying and hes right but I know I had same prob as have many others where the float gets saturated and no floaty no more, engine runs great then floods out...

 

[Willyclay]

Re: 1957 lark 35

When F_R posts, I pay attention. I had a 1959 Johnson 35 that started and ran great but would not idle. I went through that carb three times before I finally found some very hard crud in the low-speed passage that had survived soaking and spraying. Good luck with that great old motor!

 

[ddonuts]

Re: 1957 lark 35

well, I replaced all the fuel lines, vacuum lines. opened carb, blew out very thorough with air. cleaned with cleaner. still wont start. It does run spraying starting fluid in the carb, though. I think I'm getting in over my head?? If the ignition, would it still run with starting fluid?

 

[lindy46]

Re: 1957 lark 35

If it runs by spraying fuel directly into the carb, it's probably not an ignition problem. I'd still check spark with a spark tester though and make sure she's jumping a good 1/4 inch. When you cleaned the carb, did you remove the welch plug from the top of the carb, and clean the openings under there? I use a fine wire to clean out the holes, and then spray them thoroughly with carb cleaner.

 

[tmcalavy]

Re: 1957 lark 35

Do a compression test like F_R says...could save you lots of time and effort.

 

[ddonuts]

Re: 1957 lark 35

well, I had the carb rebuilt . still didnt work. none of the local mechanics knew what to do with a motor that old. ended up buying a 1980 johnson. thanks for all your inputs