Help with surging yamaha

[Khowcroft81]

I have a 97 Yamaha two-stroke carbureted Outboard. The outboard is surging at high rpm's. I also notice fuel in the water. At least I think it's fuel it's kind of a cloudy gray looking stuff floating all over the water coming out of my Exhuast. I've tried replacing the fuel pumps cleaning the carburetor is checking fuel lines. They all look good from what I can see. I also replaced every clamp on all of the fittings. I saw an old thread where a guy had the same issue and he never Posted what the result was. I wish people wouldn't do that.


Here is the thread. http://forums.iboats.com/forum/engin...=1492532506138

 

[99yam40]

need to check the lower unit to make sure what you are seeing is not coming from there.

check compression, spark ,timing and fuel pumps then go from there.

most motors have fuel problems, but need to test/check the easy things before heading off to others

 

[Khowcroft81]

I checked compression, spark and fuel pumps. Not sure how to check timing.

 

[Khowcroft81]

I just checked the lower unit today and there was no water in it and no metal shavings. I took the boat for a ride and it ran full speed no problem. It's a pain because it makes it much harder to figure out when it only acts up sometimes.

 

[thatone123]

Seems 70% of outboard problems are related to dirty fuel of buildup of varnish and deposits. Many times carb cleaning or carb rebuilt is the answer when it seems there are other problems.