90HP 2s Power loss after restart

Homosassa

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Sep 23, 2009
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Have a 1999 90hp two stroke. Starts right up, gets on plane, and continues trouble free until I stop to fish. When it?s time to move on, it will start right up but when I engage the shifter it will go into forward but the engine will not rev up. It sounds as if it?s under a great load and all I can do is idle the way back in. At some point it may correct itself or sometimes by playing with the shifter it will suddenly kick into gear and all is well again. Seems to be heat related because it never happens at the dock or if I sit a very long time it does not seem to happen. Any suggestions?
 

robert graham

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Re: 90HP 2s Power loss after restart

Same exact motor as mine and that is a mystery to me. Have you removed your motor shroud and checked all your throttle and electronic linkeages? I'll be very interested to find out what the problem is. There's some real experts on this forum and hopefully they may shed some light on your problem. Good Luck!
 

99yam40

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Sep 7, 2008
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Re: 90HP 2s Power loss after restart

Sounds like you are going into safe mode, but you are not saying the alarm is coming in.
Check to make sure your alarms are funtioning properly and that the buzzer will sound off like it should.
check your manual and see what all will cause the alarms and safe mode.
If you do not have a manual maybe Robert can give you that info.
 

robert graham

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Re: 90HP 2s Power loss after restart

These 1999 motors were premix and no oil pump or tank, so the only alarm/safe mode would be high temperature. That's a strange sounding problem and I will be very interested in knowing what it is. Good luck!
 

robert graham

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Re: 90HP 2s Power loss after restart

Check your fuel delivery system starting at the pick-up in the tank, fittings, primer bulb, quick disconnect on front of engine shroud, fuel filter, fuel pump, drain each carb and pump primer bulb to "clear" carb float needle. I believe it is a leak somewhere in that system possibly allowing air into your system. Next time it does it, try pumping the primer bulb and if that helps then it may be a bad fuel pump. Good Luck!
 

Homosassa

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Sep 23, 2009
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9
Re: 90HP 2s Power loss after restart

First of all, thanks for the quick response. As far as the alarm goes, the temperature alarm does not sound when this is occurring and the motor is peeing normally. I will go through the fuel system, starting with the fuel line with bulb (the bulb never seems to get hard). This is currently the gray vinyl looking stuff. Someone at the dock told me to get rid of it explaining that he had a lot of problems with it deteriorating with ethanol/gas fuel, but because it's relatively new I chose not to replace. I will update with outcome after the weekend.
 

99yam40

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Re: 90HP 2s Power loss after restart

Do you know if the temp alarm works when it is suppose to? With the key in the on position test it by grounding the pink wire from the temp switch on the harness side just to be sure the buzzer works.
 

robert graham

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Re: 90HP 2s Power loss after restart

There is a check valve on the end of the pick-up in the fuel tank, 2 more check valves in the primer bulb, a quick disconnect at motor that can in-leak air, and of course more places that can leak at fuel filter and fuel pump. Hold the primer bulb in the vertical position while pumping for best operation. The primer bulb really should get hard after you pump carb float chambers full and the float needles close. Leaks in this system can cause real issues in motor performance. Good Luck!
 

Homosassa

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Sep 23, 2009
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Re: 90HP 2s Power loss after restart

Thanks to all. Robert, you were right on with the check valves in the bulb. One of them was devective and a new bulb corrected the problem.
 

robert graham

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Apr 16, 2009
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6,908
Re: 90HP 2s Power loss after restart

Glad you got it fixed! A person might not think that something like a primer bulb could create a problem like that. These fuel systems seem to be very sensitive to every little thing. My 1999 Yamaha still has the original primer bulb but I've got one of those grey el-cheapo's in the boat as a spare. Maybe I should just toss it and buy a "real" spare bulb. Good Luck!
 
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