evinrude V4 clunks at wot

my 1985 evinrude v4 makes a clunk noise when i'm at wot. it only does it once and only for a secound and then runs fine the rest of the day without any trouble. it only does this after warm up and i leave the landing and go to wot. changed lower unit oil and checked for metal none found. the lower unit was rebuilt last april. any ideas on what may be causing this to happen.

Re: evinrude V4 clunks at wot

screenbuzz<br /><br />Sounds like the clutch dog is starting to slip. Could be an adjustment on the shift linkages (if it is not electric shift)> If it is on warrenty have them check it!<br /><br />Richard

Re: evinrude V4 clunks at wot

Thanks rwise for your help. i don't know much about outboard motors, so a little more help is needed. i've only owned this boat and motor about two months. the guy that i bought it from gave me the paper on where he had the lower unit rebuilt. i don't know if the warranty is transferable. i'm not sure what you mean by electric shift. please exsplain. i will try to adjust the clutch dog if it's not electric shift. i'm real handy at working on cars and small engines but i'm only beginning to learn about outboard motors. reading the questions and answers from others here has been a great help. this site rocks for us newbie boaters. any further help is greatly appreciated.

Re: evinrude V4 clunks at wot

You have a mechanical shift gearcase. OMC hasn't made electric shift motors in over 30 years.

Re: evinrude V4 clunks at wot

The 2 packs are connected together for the kill wire (black/yellow) disconnect them from each other and try it. A diode problem in the pack can cause mistriggering at high speed. Separating the packs will diagnose this possibility.....just a thought.....