Try a little more nitro %, I haven't heard of boats running on 5%. Most RTR's use 15-25% per MFG recommendations, and alot of people use more than that. I use 50% on all my engines now so far, I am running a OS CVR .12 and soon will be running an OPS .40 and a K&B .21 . I would guess 20-25% would be a good place to start, make sure you are using marine fuel too (normally marine fuel has atleast 18% oil). Just like OB said if it runs fine on shore it is probably to lean, I have to bump throttle to keep my .12 running (once it hits the water there is no sign of rich). I have been at my local pond for up to 5hrs trying to get my boats to run correctly, put the boat in the water go 30 meters and dies (over and over and over, drives ya nuts.) It should look like its spitting fuel out the exhaust a little. Where are your needles set, low and high speed? I would try 2 1/2 on the high speed and 3 on the low speed and adjust from there (on the high speed I would be careful of going less than 2 out, you could be getting too lean). What boat is this?


Paul