#2 carb extra fuel line/ electronic Fuel enrichment

[saltyworks]

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?

 

[99yam40]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

motor should turn around 5500 if propped correctly. If I could get 40000 I think mine would fly, but would be hard to cool while in the air
Did you clean the tank also? The trash had to come from there to get everywhere else.
Do you have the red lever in the normal position? open? off?

 

[saltyworks]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

Red switch in normal, will not run in emergency, using new portable tank and new 10 micron filter

 

[99yam40]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

Does that line go from the crankcase of #2 cylinder to the diaphragm pump on the Prime Start System on the #2 carb?
If so check the diaphragm for holes or tares.

If not post a picture of which one you are talking about or a better description of where it attaches

 

[rtark]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

I had the exact same problem on the same 1998 motor as yours. After I cleaned the carbs it was some better. I took the carbs off again and found that the thin plastic diaphram in the enrichment pump was torn. Ordered one for $6 and got it in the water today and it runs great at any speed. A torn diaphram will cause all kinds of problems. That is twice in one year so I am getting some experience with them. This time I didnt pay a mechanic $150 labor.

 

[rtark]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

Forgot..
There are 2 hoses coming off the fuel enrichment pump, a short black one and a longer silver one. You can't get them wrong. The short one goes to the middle carb and the silver one to the top carb. I took lots of pictures and here is the best view I had. I hope this helps.

 

[saltyworks]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

its the short black one. nowhere in my shop manual (selco) does it talk about the efe vavle, is the where is the diaphram? If I cap of the line going to the cylinder would that help for know, it might take a few days to order the part?

 

[99yam40]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

The diaphragm is under the plate that the red lever valve is attached.

 

[rtark]

Re: #2 carb extra fuel line/ electronic Fuel enrichment

Selco manual for 1997 through 2003 2 strokes. Pages 3-46 through 3-49 tells all about the EFE pump with exploded views and instructions. The only way to know if it is the diapham is to take the cover off and look at it. Not a big deal. Good luck.