motor wont run in the water

[Guest fishintbay]

I recently purchsed a 40hp outboard it runs and starts awsome in the drive way with the ear muff on but when i put in in the water , its having a tough time starting and when i do get it started i will run at a low speed at full throtle for a few minutes the die . any suggestions and what will be the cost

[Garbie 7]

Did the motor sit for a while? I would try cleaning the carbs. A outboard motor needs next to no fuel to idle without a load in the driveway, but once it is in the water, and you put a load on it (even just the water pump) it needs quite a bit more. My guess is your carbs are gummed up with stale gas. Best thing to do it tear them down and clean/rebuild them, you might be able to get away with just a carb treatment (seafoam is excellent) but you might end up running lean on one or two cylinders if you don't get them fully cleaned. I ran seafoam in my 115 and it helped alot, dumped a bunch in the throat of the carbs while it was running, then let it sit and restarted. I then mixed a heavy concentration in a plastic jug and let the motor idle, running off this mixture, every once in a while i would blip the throttle in hopes of getting through the main jets. Then i mixed a cruise-a-day 50:1 (oil injection still on motor) with seafoam pretty concentrated and took it out on the water and ran it on and off the throttle. It has taken a while but it has gotten way better than it was (only 3 cylinders before). Now I just use the seafoam as a stabilizer in the gas. You have to be careful though, a 2 stroke needs gas/oil to each cylinder and without it things go bad real quick, also I am not sure how concentrated you can mix the seafoam before it might damage a motor run at WOT.

[Guest fishintbay]

Thanks ill try running some seafoam through the carbs, i think i have some water in the fuel also