Electronic fuel enrich

[saltyworks]

#2 carb extra fuel line/ electronic Fuel enrichment
I have a 98 40hp 2stroke yamaha. It started to run badly I found the inline plastic fuel bulb/filter filled with stuff, I have cleaned/rebuilt all 3 carbs as well as the fuel pump. When i first ran it it seemed better but still only producing about 3200 rpm, I think closer to 40000 is normal. I remembered that there is a fuel line that go,s right from the 2 to carb to the cylinder that I has forgot to hookup, after i hooked that line up, it was back too only 2000 rpm? Could I have a problem with the electronic fuel enrichment valve , I wonder if I caped off that line if it would run normal, without the fee?

[boats.net]

Probably not the enrichment valve thats the problem, check that the red lever is in normal position.

[saltyworks]

Red lever in normal, in fact it will not run in emergency

[99yam40]

Can you post a picture if the line you are talking about?
It may be the line that feeds the pulses to the diaphragm in the prime start system and if that diaphragm is ruptured it could be sucking fuel directly into the crankcase flooding out a cylinder

[saltyworks]

I will try, but it is the line that comes out of the #2 carb and goes directley into the head.

[saltyworks]

on closer look the line comes off the fuel enrichment device that is connect to the #2 carb

[saltyworks]

pics one with no hose is of carb/fuel enrich, the other is the cylinder were the hose go,s

[99yam40]

Sorry I still can not tell from the pics where it attaches on either end.

You said attaches to head, The head is on the back of motor where the spark plugs screw into. Is that where it really goes?

On my c40 the gray line runs from the prime start system between the thermal unit and carb to the intake behind the #1 carb see top red arrow
and the black hose next to the gray one goes to the top of carb #2 vent of carb.
The other black line runs from the bottom of the prime start system to the motor crankcase see red line on bottom of pic.

Which one are you talking about

[saltyworks]

Your corect it's not the head it's the cylinder, I think it's the fuel line that bypasses the carb and puts fuel right into the engine, if my efe in stuck open and cap off the line will it run at full power? In the pic the brass fitting with no line on it is the back of the efe valve, no other pic is were that line leads to

[saltyworks]

it may help when I took the 3 carbs off there were 2 fuel lines I had to disconect, the one that comes from the fuel pump the connects go the tee that feeds all 3 carbs, and the one I am talking about.

[99yam40]

If it is like my 99 C40,the one that comes off the back should be hooked to the place the bottom red arrow is pointing at in my pic.
That is the pulse to the diaphragm pump.
The top arrow is pointing at the place the enriched fuel mix inters the intake manifold and feeds all 3 cylinders through internal passages.
On mine I had to remove 3 lines to take off the carbs,yours maybe completely different than mine if you only had 2.
Turning the red lever to off will close off the fuel from the enrichment system to the motor, but if the problem is the diaphragm then the fuel can be sucked into the crankcase through the pulse line