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Mercury 115 hp won't rev up past 2500 rps under load.

S

snider7

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I have a 1996 115hp mercury tracker motor. It will rev up to 5500 rpm's when in neutral out of water. When I put it in gear and take the pontoon boat out it will only rev up to 2500 rpm's.

I took it to a reliable marine mechanic and I water coming into 2 cylinders. I had a cracked intake gasket and he replaced that. He figured that was the problem, the water was fouling out two cylinders.
I brought it home and winterized it We got it out today, started it at the house, put it in the pond. Well it still does the samething. It wont rev up past 2500rpms You throttle it up halfway and it goes to 2500rpm but once you give it more throttle it stays the same rps and speed.
 
..."cracked intake gasket "

Sounds like the exhaust plate is leaking water into the cylinders. Better find a far more "reliable" mechanic.

Jef
 
How long have you owned this motor ?----Start with a compression test.----Check for spark on all 4 leads too.---------Has this motor sat for any length of time.-----Have you checked if oil injection is hooked up and working properly ?
 
snider7 said:
I have a 1996 115hp mercury tracker motor. It will rev up to 5500 rpm's when in neutral out of water. When I put it in gear and take the pontoon boat out it will only rev up to 2500 rpm's.

I took it to a reliable marine mechanic and I water coming into 2 cylinders. I had a cracked intake gasket and he replaced that. He figured that was the problem, the water was fouling out two cylinders.
I brought it home and winterized it We got it out today, started it at the house, put it in the pond. Well it still does the samething. It wont rev up past 2500rpms You throttle it up halfway and it goes to 2500rpm but once you give it more throttle it stays the same rps and speed.
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Kinda sounds like your rev limiter might be kicking in
 
racerone said:
How long have you owned this motor ?----Start with a compression test.----Check for spark on all 4 leads too.---------Has this motor sat for any length of time.-----Have you checked if oil injection is hooked up and working properly ?
Click to expand...

I have owned it for 9 years. It has been run every season. Compression test and fire to all leads is good. Oil injection is working good.
 
snider7 said:
Is that a sensor
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Its a sensor or module that prevents you from blowing up your motor from over reving the engine. Its mounted below your oil tank most likely. You can unplug it but keep in mind it there to protect your engine so if you unplug it and fixed your problem replace it. Don't just run without it
 
Just wanted to update everyone in case you run into this problem. We went through pretty much everything including changing the coils and nothing helped and we decided to pull the fuel injectors and found that one oring on one injector was split so we ordered new ones put them on and it runs amazing now. Hope this helps someone down the road
 
zlaxton22 said:
Just wanted to update everyone in case you run into this problem. We went through pretty much everything including changing the coils and nothing helped and we decided to pull the fuel injectors and found that one oring on one injector was split so we ordered new ones put them on and it runs amazing now. Hope this helps someone down the road
Click to expand...
The OPs motor was a 2+2 carbed motor it DOES NOT have injectors! I think your motor is newer and has nothing in common with the OPs motor.
 
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