Evinrude Lark III - carb/float question

[Gas Giant]

Model # 35524 1961 40hp

I just finished rebuilding the carburetor on this engine. Did a full rebuild; tore it down to a bare shell (even took out those welch plugs), soaked it in carb cleaner, blew out all the passages and put it back together with an OMC kit. Its sparking clean now, inside and out, and nearly everything inside the carb has been replaced. (Also replaced all the fuel lines on the motor, the fuel filter, and tore down and cleaned out the fuel pump).

I was pretty sure I set the float height properly - the manual has the standard procedure where you flip the carb over and make sure the float is sitting horizontal - so I did that before putting it back together. However, when I went to prime the fuel system to start it, I started getting gas leaking out of a hole on the front of the carb. It would also do that when I cranked it with the pull starter (I disengaged the ignition before trying, I was just curious as to what was happening).

So I took the carb off and adjusted the float again, even though it seemed right - but my question is, other than the float valve (which was replaced as part of the kit, along with the seat) is there anything else that can cause the carb to leak fuel from the small hole in the front of the carb? (I didn't get a chance to put the carb back on, a storm rolled in and that's keeping me inside)

It didn't do that before the rebuild, but I am pretty sure it was so crudded up before the rebuild that no gas could get into it! :facepalm:

Any advice is appreciated. Just got this boat registered today, so I am looking forward to being able to finally take a boat out!

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

Just put it back on after tweaking the float - it made no difference. Also played around with the low speed needle, and it made no difference. The hole the gas is leaking from is circled in red below:

Does anyone know what causes fuel to leak out of this hole? Is it supposed to? Is it some sort of overflow protection? I'm pretty confused, but that happens easily.

If it isn't supposed to happen, does anyone know what could cause it? The fuel system is the last thing I need before a test drive; and its entirely complete except for this stupid problem! (If it is a problem....)

 

[nwcove]

Re: Evinrude Lark III - carb/float question

im not sure about your problem, but will respond to "bump" you back to the top, where the guys who have seen the problem before can offer advice.

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

Thanks! Its frustrating having put all this work into it only to be stopped by a problem you don't really understand.

 

[nwcove]

Re: Evinrude Lark III - carb/float question

dont get discouraged, those oldies are pretty simple, and there are very knowledgeable people here that undoubtedly seen this issue, and know where to point you.

 

[F_R]

Re: Evinrude Lark III - carb/float question

That is the bowl vent valve. Obviously the float and/or float valve are not doing their job. I cannot tell you why they aren't from here. Could be something interferring with teh float acton. Could be a piece of something stuck in the float valve needle/seat, holding it open. Or the parts could be defective (it happens)

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

I'll tear it back apart and check, and post some pics if I can get some good ones.

 

[todd57]

Re: Evinrude Lark III - carb/float question

Does this model have the high speed pickup tube that comes down the center of the carb bowl? If so, did you remember to replace the round gasket that slides over that center tube? I've read people say that causes gas to leak out the carb overflow. I can't find a diagram of this carb, so if it's a dumb question, sorry for wasting your time.

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

Well, I feel like an idiot.

I took it back off the boat, and took the float and float valve out as I noticed the valve was sticking. When I looked down into the seat, I noticed that there was a piece of old gasket in it. How that piece of gasket got in there in the few seconds between me installing the seat and installing the float valve I may never know. I bet that was the problem.

I'll post the results tomorrow, even if it makes me look stupid!

Tood: Yes, it does have that gasket. I spent a lot of time figuring out what went there, because when I took the carb apart, it wasn't recognizable as a gasket! Fortunately, my PDF manual answered the question (after awhile of reading on a slow computer.....)

 

[Joe Reeves]

Re: Evinrude Lark III - carb/float question

Clogged float bowl vent. Clean it.

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

Joe, just to be sure, I'll take a look - do you know where that vent is? I'm not sure myself.

 

[nwcove]

Re: Evinrude Lark III - carb/float question

looks like you've found the issue. ( this forum is such a wealth of knowledge!....in a time where most people want $$$ just to tell you its going to cost $$$$ before you get help!

 

[F_R]

Re: Evinrude Lark III - carb/float question

Joe, just to be sure, I'll take a look - do you know where that vent is? I'm not sure myself.

The vent is the hole that the gas is pouring out of. Nuff said.

 

[Joe Reeves]

Re: Evinrude Lark III - carb/float question

With the float chamber removed, look very closely at the bottom portion of the upper body. You'll see a hole that will be the access point to the vent passageway. At some point, that passageway is clogged. This is a common problem. Let us know what you find.

 

[Gas Giant]

Re: Evinrude Lark III - carb/float question

I was able to spray carb cleaner freely through the vent hole. I got the carb back on the motor, and the fuel leak is fixed. Thanks guys.

 

[jarodstrain]

Re: Evinrude Lark III - carb/float question

Well, I feel like an idiot.

I took it back off the boat, and took the float and float valve out as I noticed the valve was sticking. When I looked down into the seat, I noticed that there was a piece of old gasket in it. How that piece of gasket got in there in the few seconds between me installing the seat and installing the float valve I may never know. I bet that was the problem.

I'll post the results tomorrow, even if it makes me look stupid!

Tood: Yes, it does have that gasket. I spent a lot of time figuring out what went there, because when I took the carb apart, it wasn't recognizable as a gasket! Fortunately, my PDF manual answered the question (after awhile of reading on a slow computer.....)

Hey - I know this is an old thread but on the off chance someone's watching it, do you have a copy of that pdf manual. I'm going crazy trying to find one.