'88 Evinrude 40 VRO

[Ultrium]

Recently purchased an '89 fisher boat with a '88 Evinrude 40hp VRO (model# E40TLCCS) The engine cranks on the first hit, idles, takes off and runs great up until around 75% throttle. At that point, the engine starts to make a slight chattering sound. Not knowing what it was, I came home and pulled the plugs looking for detonation. The plugs, which weren't the correct one, were black and wet from what looked like too much oil/fuel. I went and purchased Champion QL77JC4 plugs but haven't had a chance to try them yet. I have searched for another example of this on this forum but haven't found anything yet. Has anyone experience anything like this?

Thanks

 

[JB]

Re: '89 Evinrude 40 VRO

Re: '89 Evinrude 40 VRO

Haven't heard of that before, Ultrim.

BTW, your engine is an '88 model, not an '89. It might have been a leftover first sold in '89.

 

[Ultrium]

Re: '89 Evinrude 40 VRO

Re: '89 Evinrude 40 VRO

Thanks for the info.

 

[Ultrium]

Re: '89 Evinrude 40 VRO

Re: '89 Evinrude 40 VRO

****Update*****
I took the boat out this afternoon w/ the new (correct) plugs and ran some sea foam through it. The engine was making the same noise around 75% throttle and not reving all the way up, then all at once, the engine came alive and it jumped prob 1500 rpm's and 10 mph on the gps. It ran GREAT until, I backed the throttle down, then it started making that sound again around 75% throttle. After a few seconds, it came alive again and ran fine, until I backed the throttle down again. This next time, it never came alive again and continued to make that sound. Has anyone ever seen or heard anything like this.

 

[hidef]

Re: '89 Evinrude 40 VRO

Re: '89 Evinrude 40 VRO

Have you cleaned the carbs? It sounds like it is starving for fuel.