1998 115 hp Mariner will not rev over 2500 rpm

desotoboy

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Apr 14, 2014
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My 115 Mariner ran fine last year and this year it is acting up. It will start and run fair but when I open it up it will not run over 2500 rpm. When I turn on the key the buzzer sounds and after I start it, it stays on. Today, hooked to the hose, it would idle a little fast then cough and drop about 500 and then go back up. Help !
 

Chris1956

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Mar 25, 2004
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Re: 1998 115 hp Mariner will not rev over 2500 rpm

sounds like a compression test and a spark test are in order. Are you running the oil injection system? What does the alarm mean? Overheat?
 

desotoboy

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Apr 14, 2014
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Re: 1998 115 hp Mariner will not rev over 2500 rpm

I am running the oil injection system that seems to work. The compression is good on all four cylinders and when I have it running on the hose and remove the plug wires one at a time, the top two make a big difference but the bottom two don't seem to effect the operation very much.
 

racerone

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Dec 28, 2013
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Re: 1998 115 hp Mariner will not rev over 2500 rpm

The bottom 2 cylinders do not operate the same as the top 2 cylinders when the motor is idling !!!---They do not produce power at idle !-----Part of the design of this motor.---You need to test for strong spark on all 4 cylinders.---Strong spark means it should jump a gap of 7/16" or more.----Before running it out on the lake you must confirm that carburetors are all clean.---Confirm that all 4 carburetors are opening fully too.
 

Faztbullet

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Mar 2, 2008
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15,589
Re: 1998 115 hp Mariner will not rev over 2500 rpm

Also check accelerator pump and injectors....
 

desotoboy

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Apr 14, 2014
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Re: 1998 115 hp Mariner will not rev over 2500 rpm

Thanks so much for the info. I will check the spark and the carbs and probably have to have them cleaned. I appreciate The help Gentlemen.
 
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