Help With Evinrude 40Hp 2 Stroke Problems

[Finnz922]

Over the last year our older Evinrude 40hp 2 stroke has developed a most annoying issue. It works fine when hooked up to a hose or in a large trash can filled with hose water, but when we get in in a lake it idles terrible and cuts out when under 5mph and in idle. Seems like it struggles to get fuel but like I said it works fine at home at all speeds and in idle. Have any of you experienced anything like this? We have taken it in to a guy almost a half dozen times and he says the motor is in great shape and works fine which is comforting until we get to lake and it's deja vu all over again

[freebie]

sounds like you need to clean your carbs and set your linkage. if you have a repair manual and follow directions it's isn't too bad to do yourself. if you're not inclined to do it yourself shouldn't be more than a couple hundred at the mechanic. make sure whoever is fixing it will run it in the water and make sure it is good.

[jhoffman]

Play with the idle adjustment needle. If its a two stroke, thats just how they are, especially when cold.

[Nitrofreak]

Sounds to me like the engine is setting too deep in the water and covering the exhaust port,  have you checked that out?

[Way2slow]

When you say "Older" that don't help a whole lot as to what carburetor it has. 

 

First off, you can't adjust anything about a carb (idle speed or mixture) while connected to a hose or with the LU just covered in water.  The ONLY way you can properly adjust one is when the motor is sitting in the water submerged at the depth it normally sits while in the lake.  There is no way you can get the proper back pressure with the motor out of the water.   Trim angle can even affect some carbs.  You will notice most motors idle very high and sometimes will lean spit when on a hose, that's caused by the lack of proper back pressure.

 

Depending on the carb you have, some can be a little tricky to clean and adjust, and could just be bad.  I've got a carb off a 1988, 48 Johnson that after four different times of taking it apart and cleaning, (and I know very well how to clean and adjust them) and it still wouldn't idle, I finally replaced it with one I rebuilt off another motor and it ran like a champ.