Re: 20 hp Mecury 4 stroke
Hello from the UK!
Have you checked the oil level?
In 2008 I bought a new Mariner 20hp electric start 4 stroke (which is similar to the mercury model)via the internet.The pre delivery inspection was done by the main dealer before shipping with oil drained from the motor. A litre bottle of 4 stroke enclosed with the motor upon delivery which was the oil capacity. I was instructed to simply to por in the oil and run the engine. It immediately acted similar to yours. I checked the oil level dipstick and found I had over filled it! I drained the excess oil to the recomended level and had no more problems. I hope this helps if not wiser heads may help.Regards, David
