1961 evinrude lark3 40hp carb

[osagehun]

I read in the manual that there was a fixed speed carb and then there is a variable speed carb. On the variable, one needle for the low speed (idle) and another for the high speed.

The carb I have has one needle and it seems you turn it to the left for low speed and to the right for high speed. Am I to find some level in between?

 

[F_R]

Re: 1961 evinrude lark3 40hp carb

Nah, you got it wrong. I do hope you are speaking of the needle valve in the top of the carburetor. It controls the fuel/air mixture for idle speed only. Turning it to the left makes it richer, right makes it leaner. Any internal combustion engine requires a narrow range of fuel-to-air mixture. The needle accomplishes that. As I said, it affects idle speeds only.

The high speed is a fixed jet (orfice plug) in the very bottom of the carburetor, deep in the hole behind the slotted hex head plug. It is calibrated for the correct mixture and is not adjustable.

 

[osagehun]

Re: 1961 evinrude lark3 40hp carb

Thats makes more sense, thanks!

One more question. As I was taking the carb apart today, (expecting to see "gum" in the bowl and elsewhere), it looked completely clean, shiny actually.

Can a carburetor be gummed up even if I don't "see" any?

 

[tashasdaddy]

Re: 1961 evinrude lark3 40hp carb

yes in the jets.

 

[F_R]

Re: 1961 evinrude lark3 40hp carb

What is the nature of the problem that is causing you to tear the carburetor apart?

 

[osagehun]

Re: 1961 evinrude lark3 40hp carb

The engine did not seem to be getting gas because there was a spark and it wouldn't start. So I disassembled the carb, cleaned it replaced all the parts that came with the carb repair kit, then reassembled.

So now I have gotten back from trying to start her and she showed signs of life. It "popped", once when I was using the pull start.

I checked to make sure the tube from the gas to the carb was clean, it was.

I guess the next step would be to absolutely make sure there is a good strong spark?

Can you check compression w/o starting the engine?

And lastly, if I know the battery has a full charge and the electric starter doesn't budge, (no solenoid, and I guess the cables could be bad but not especially likely), does that mean the starter needs rebuilding?
(it died trying to start the engine over and over)

Thanks for any response

John

 

[F_R]

Re: 1961 evinrude lark3 40hp carb

Here I go again...Check the coils. They are notorious for being bad.

Of course you can check the compression without starting the engine. That's the way it always is done.

As for the starter...???

 

[steelespike]

Re: 1961 evinrude lark3 40hp carb

You should really be working with a manual.If you have no starter reaction
at all it could be the neutral safety switch.Could be out of adjustment disconnected or you have it in gear.Don't assume anything on a 46 year old motor.Check all connections for clean and tight.Don't forget the negative side.You may have burnt out the starter.You can hand crank to check compression.Some of these motors have a compression release that activates when you pull the rope.It is on the cylinder head and resembles a 4 stroke valve rocker arm.
unless you have changed the coils you should assume they are bad on these old OMC motors.You may be able to inspect them through an opening in the flywheel.If they appear cracked or discolored you should assume they are bad.Coils are readily available at E/J dealers,right here at iboats or at NAPA auto parts.You could try to start it by CAREFULLY squirting fuel mix into
the carb opening.If she fires up then you have a fuel supply problem.
Double check all carb passages and jets are clean.

 

[samo_ott]

Re: 1961 evinrude lark3 40hp carb

If the starter did work and it does not now, that's not a good thing. There are several things in the wiring path that could stop it though. Bypass them all to verify it. To do so get jumper cables and hook the positive of the battery to the lower side positive terminal on the starter. Then hook the negative from the battery to a good ground on the engine. Be prepared for a big spark and a jolt if the engines turns. Secure it first.

If this works then test the compression. Remove both spark plugs and screw in a compression gauge. Then turn the engine over 5-10 times to get a good reading. Do this for both sides and come back and post the results.

 

[osagehun]

Re: 1961 evinrude lark3 40hp carb

Mucho appreciation

So I just got back from getting the compression checked. 55 on one side and 75 on the other. I think I read somewhere that 80 was good. So the mechanic said it was probably a bad ring.

But the best thing to happen in 3 mos. It almost freaking started in the parking lot!

And the starter is at the shop now.

I will check the coils next.

Ya'll rock, thanks

 

[HighTrim]

Re: 1961 evinrude lark3 40hp carb

A decarb my help even those numbers out, look in the FAQ for the proper procedure. Good luck.