Logo
FULL SITE MENU

Evinrude 40 Big Twin crank no start

T

Tryloff

New member
Hey all, I'm not new to wrenching but this is my first boat. I have only owned it for a few month but I cant get it started. I'm going to write down everything I know about it to hopefully help answer many questions.

-When I got it, the cylinder head and cover were cleaned and had new gaskets so I assume someone was in there recently.
-I tested compression and have 105 on the lower cyl and 110 on the upper.
- points, condensers, and coils are all new and set correctly. .020 for the points as the manual and flywheel both say, and coils are positioned correctly.
-spark verified by a spark tester on both cyl. Looks like it may be weak? But sparks reliably.
- new plugs. M42K part number.
- starter rebuilt, it spins very fast, can't get rpm reading while cranking from the front.
- I rebuilt the carb with both the parts manual and the service manual right in front of me. I'm fairly confident I did it correctly, but it's the first time I've done this specific carb.
-It has ran for about 10 minutes total since being back together. It never ran well.
- when I pulled the plugs out for compression test, they were soaking wet. I was able to fling moisture off on to the shop floor. I'm assuming fuel/oil but it wouldn't light on fire with a lighter held to it.
- the 5 gal gas tank was about half full when I got it. I put 1.25 gallons of fresh 40:1 in it before messing with it.


I'm going to mix a fresh batch of fuel and try to run it off of that with new spark plugs. I'll report back what I find.

Any other suggestions are more than welcome.
 
The answer is obvious. You gotta find out if that is fuel or water in the plugs. I am assuming water. If so, you either have a major water leak into the cylinders or you have a gas tank full of water.
 
Drained carb and mixed a fresh half gallon of fuel. Still crank no start on new (clean used) plugs and fresh 40:1 fuel. It did backfire pretty loud at the end of the second bit of cranking I did.

fdrgator said:
The answer is obvious. You gotta find out if that is fuel or water in the plugs. I am assuming water. If so, you either have a major water leak into the cylinders or you have a gas tank full of water.
Click to expand...
That last bit of cranking I did there was no water hooked up to the engine and fresh gas. I'm in need of a new obvious answer.
 
So remove the drain plug from the bottom of the carburetor. What comes out, gas or water?
What model motor is it anyway? Is it one with a water heated choke? Hoses mixed up?
 
As stated in the last reply, I drained the carb. Gas came out.

It has no water heated choke. There's a tube from the crank case to the choke that let's warm crank case gasses heat the carb.

The model is a big twin. As stated in the first post. 40hp, 2 stroke, I think 1963 model year?
 
Hot air choke didn't appear till 1964.

So if it ain't water in the plugs, we are saying it is fuel?

There should not be so much fuel in the cylinders that you can shake it out of the plugs. If there is, the carb has a problem such as a missing high speed orifice plug, or it is getting in there by some other route. Such as a ruptured fuel pump diaphragm.

I'll pass now.
 
Back
Top