WOT = Motor that misses

[nebraska_woody]

Hopefully this will spark some interest with someone in the forum who can help me. my motor has been recently decarbed and idles fairly well now, but at WOT and sometimes 3/4 throttle the motor feels like it misses. it does this at random (sometimes very quick in between times, and other times only when it's cold and occasionally). The motor itself jerks and bounces when it does this and causes the boat to slow down for a split second until it catches up again with itself. I dont understand what is causing this. I think I have slightly low compression as well. Anyone have any idea's please? i'm stumped!!!!!

 

[DaleT]

Re: WOT = Motor that misses

Sounds like you may be due for a carb cleaning, if you haven't already . Just decarbing won't clean all the gum out of the carb. Try adding the make, hp, and year and I'm sure someone on this board can give you a little better insight than I can.

 

[durk187]

Re: WOT = Motor that misses

I would agree with Dale.<br /><br />Had the same problem with a 66 evinrude. Cleaned carb and now it runs great.

 

[SHANKS]

Re: WOT = Motor that misses

hi <br />got the same problem on a 70hp mercury..have been told it could be cdi unit playing up..

 

[nebraska_woody]

Re: WOT = Motor that misses

thanks guys for replying.. yeah, sorry about forgetting to give the details. I have an 89 johnson GT200. I dont know that much about it, but only once in a while does it spit and sputter just slightly at idle now after decarbing it. I spent about 3 weeks with a half dozen different occasions of spraying the cleaner in the carbs and stuff. Since then, it idles better than it did before, but i had it out last night and the boat still misses as I said before and for some reason, it spit and sputtered more than usual. My mechanic told me I should be running a premium gas in the boat, as he says was made for that. Anyone have an opinion on that? I dont believe that is making the motor miss, but any suggestions are appreciated. thanks again

 

[Deerdog]

Re: WOT = Motor that misses

Nebraska,<br /><br />Last year my Foce was doing similar things - intermittent missing. It turned out to be electrical - a stator. Have you ruled out a bad plug or plug wire? <br /><br />As to fuel. I used to also believe that 93 Octane was best for the motor and it did seem to me it ran better ..........but I now run 87 (a good brand such as Amoco) and the motor does just as well. If you manual calls for high octane then do it but if it doesnt Im here to tell you that a good grade 87 will probably work fine - unless there is something about Johnson's I am not aware of.<br /><br />Good Luck<br />Deerdog

 

[nebraska_woody]

Re: WOT = Motor that misses

What exactly is a stator? i've heard other people talking about them, and replacing them.. etc..etc..etc.. but what exactly does it do and where is it at? I actually have not ruled anything like the plugwires out or anything yet. I have changed plugs 2 times this year so far, but to no major change in how it runs. The plugs are slightly wet (not soaked)and dark. the right bank(driver side) seems to be just a little dryer than the left bank of plugs is, so i'm not quite sure what that means either.Would that have something to do with this so called stator? thanks for any input again.

 

[Jumper]

Re: WOT = Motor that misses

Not being a motor expert, I'm going to take a wild guess on this going off of what I've learned/read on this forum. You said the right bank is dryer than the left. It could be those plugs aren't getting enough fuel. Or at least your problem may be fuel related. Sounds like a carb cleaning is in order. Set me straight guys if I'm wrong.

 

[Jumper]

Re: WOT = Motor that misses

PS. Woody, being a Huskers fan, I have to wonder about your name and your location (Iowa).

 

[BKool68]

Re: WOT = Motor that misses

I believe the problem is the wet plugs not getting fire. Switch the packs from side to side and see if the wet plugs jump.

 

[nebraska_woody]

Re: WOT = Motor that misses

LOL.. Hey Jumper.. i'm in sioux city. Born and raised in Beemer Nebraska though, so yes, born and bred with the huskers...lol. Where are you at? As far as the rest of the reply's that's a good idea.. i dont know how to switch the packs on there, but I will find out and hopefully do something and try that little experiement next week after the weekend is over. I just wish this thing would run like a top over the labor Day weekend Thanks again for the reply's and I'll look for more tomororw morning. nite nite