Evinrude loss of power

I have a evinrude 70hp 2 stroke (94ish model) - yesterday I took it for a run as I hadnt ran it for a few weeks... It worked normally for about 20 minutes (about 30mph), I then saw a little dingy in distress and went over to help them and threw them a rope to start towing them back. once the rope was tied on I powered the engine but all the power seemed to disappear, I put this down to the fact that we were just towing.. after about 30 seconds of towing they got there boat going so we set them free... I then went to take off and still had the major loss of power... I had it flat out on the throttle quadrant and it was only going about 5-8 knots... I had to travel like this all the way back to the boat ramp which was about 10 mins away (1 km)

any suggestions???

Re: Evinrude loss of power

I'm a little bit confused on the loss of power, does it act like you spun a prop or is it more the engine not running well? have you checked your compression, spark, and prop? what do your sparkplugs look like?

Re: Evinrude loss of power

was your rpms up like you were cruising? or was it stumbling or bogging?