Problem w/ '02 Mercury 90
buddy of mine (Nathan Kjellman on here) has an 02 mercury 90hp carb'd 4 stroke and its having a few problems we are both trying to figure out.
recently the motor has had the carbs rebuilt, spark plugs changed, impeller replaced, and the primer ball replaced. here is whats going on (hopefully i can describe it ok) now this isnt happening all the time, it is just happening at random sometimes. the motor will start up just fine and idle fine. you put it into gear and start going at slow speed and everything is ok. when you start to give it gas itll start to bog down and not go above about 2k rpms. itll putt and chug like its misfiring, but when you bring it back down to an idle its just fine. you then could shut it off and 5 min later start it up and itll run just fine all the way up to WOT.
Now recently a rock was hit while idling through some narrows, it did chip up the prop alittle bit. we were wondering is there some kind of balancer in the lower unit of the motor? kind of like a harmonic balancer on a car engine? and maybe that just got knocked out of wack? also recently there has been a warning siren coming on. we were told by a marina that a wire might be grounding out on something to cause the siren. you can reach up under the counsel and move a group of wires and itll stop, but the same marina had said that these warning sirens are caused by either bad impeller or oil problems.
any guesses? any info at all is greatly appreciated. we are headed to my dads in madison soon and would like this problem fixed. like i said any info is greatly appreciated.
thanks a lot, Brian
recently the motor has had the carbs rebuilt, spark plugs changed, impeller replaced, and the primer ball replaced. here is whats going on (hopefully i can describe it ok) now this isnt happening all the time, it is just happening at random sometimes. the motor will start up just fine and idle fine. you put it into gear and start going at slow speed and everything is ok. when you start to give it gas itll start to bog down and not go above about 2k rpms. itll putt and chug like its misfiring, but when you bring it back down to an idle its just fine. you then could shut it off and 5 min later start it up and itll run just fine all the way up to WOT.
Now recently a rock was hit while idling through some narrows, it did chip up the prop alittle bit. we were wondering is there some kind of balancer in the lower unit of the motor? kind of like a harmonic balancer on a car engine? and maybe that just got knocked out of wack? also recently there has been a warning siren coming on. we were told by a marina that a wire might be grounding out on something to cause the siren. you can reach up under the counsel and move a group of wires and itll stop, but the same marina had said that these warning sirens are caused by either bad impeller or oil problems.
any guesses? any info at all is greatly appreciated. we are headed to my dads in madison soon and would like this problem fixed. like i said any info is greatly appreciated.
thanks a lot, Brian
Replies to This Discussion
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Permalink Reply by Bill Barkley on -
Brian,
Not sure on a new motor, I say new cause mine is a 1989 Johnson, but it sounds like the same thing mine kept doing. It was especially scary coming around Cyclone Point out of Sabaskong going to Morison on LOW is 4+ footers. I replaced the overheat sensor (easy to get at and change) however this happened again and again. When it did I could hold my hand on the motor and it wasn't even that hot. So, I disconnected it and it hasn't given me any more problems. I am not telling you to disconnect it on your motor, but you might try replacing it or unplugging it to see if it lets the motor go to full speed. Bark
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Permalink Reply by Joe Andrews on -
I don't have a four stroke...I have a two cycle, but a couple years ago I had a similar problem. My mechanic told me that the power pack was smoked. The power pack is what distributes the power to the spark plugs. So my boat was firing on all three plugs and then out of nowhere it would go down to one, so it would be choking and struggling, but wouldn't die. Sometimes it would run fine for a while, but I knew there was something wrong. We messed up the power pack by jumping the 12 volt starting battery off of the 24 volt trolling motor batteries. It definitely worked great, but I paid the price for it. Luckily the mechanic is a friend of a friend so I got it fixed for the cost of the power pack (about 250 bucks) and I gave him 100 bucks for putting it in. HOpe this helps or gives you a new idea.
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