surging at WOT

[mikeyzx2]

Hi ya'll I'd like to welcome myself to this forum and I hope I learn alot from all of you! Anyways the problem I have is the engine is surging at WOT. Mash the throttle all the way down and it doesn't quite reach full throttle then it'll surge and back off, and so forth. It doesn't sputter or miss. It's a 1977 85HP Evinrude. The lady at boat shop told me it's likely the powerpack, I don't have test equipment so don't know first steps to take and would like some feedback before I move ahead. Thanks

 

[Barnacle_Bill]

Re: surging at WOT

That sounds more like a fuel problem. Check your tank vent and be sure it isn't plugged. Check all your hoses and primer bulb. They should all be soft and pliable. I recently had the same problem on my 83 Merc 150. It turned out to be one of the new hoses I put on. I had tightned the clamp down too tight causing a crack in it.

 

[chris in va]

Re: surging at WOT

FWIW, I had the same issue with my 9.9 recently. Found out the carb float was misadjusted, periodically starving the motor of fuel. It would bog somewhat at WOT, but run fine at 3/4.

 

[mikeyzx2]

Re: surging at WOT

Thanks for feedback. Okay this is an ongoing project bassboat I've been fixing up since December. I've done absolutely nothing to motor as of yet, I ran it on the muffs the day before I actually took it out. I did put a brand spanking new fuel line and bulb on it and put a couple gallons of gas in it. It has a pretty decent tank, around 12 gallons I think, and I'm wondering if I may need to pull it and flush it out. The spark plugs were pretty oily too, I just put new ones in it but not started yet. Do ya'll think it's possible one of the high speed jets is clogged on the carbs? I haven't tore into the carbs yet unless it's necessary. Thanks