2001 Mercury 150 Optimax rpm fluctuation

N

npanthony

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Jun 11, 2006
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I have two 2001 mercury 150 opti's and when we are running the boat the port motor will drop rpm's. we have taken the boat to a repair shop and after some relay replacements and the suggestion to change the batteries we are still having the same problem. the rpm drop is usually about 3-4 hundred rpm's and then returns back to the running rpm. even at idle the motor is cutting out. diagnostics is showing nothing about timeing or fireing order and comperssion checks are good. next step in the process is to check the alternators. with the twin motors, one dropping rpm's is making the steering a little difficult on plane. thanks for the help
 
S

sport15

Petty Officer 3rd Class
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Jun 1, 2006
Messages
95
Re: 2001 Mercury 150 Optimax rpm fluctuation

Do you have separate fuel tanks? If so try swapping fuel systems, (port tank to stbd engine) if the problem transfers it is fuel. This happened to my Dad's boat many years ago. It ended up being a small amount of water in the port tank. <br /><br />What happens when you advance the throttle with the RPM loss? How frequently does this happen?<br /><br />It just seems odd that it would be electrical, what am I missing???
 
N

npanthony

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Jun 11, 2006
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Re: 2001 Mercury 150 Optimax rpm fluctuation

fuel feeds are from same tank. it fluctuates very often and when throttle is advanced past fluctuation, rpm's will catch up to advancement. it seems to fluctuate most around 3000 rpm's.
 
S

sport15

Petty Officer 3rd Class
Joined
Jun 1, 2006
Messages
95
Re: 2001 Mercury 150 Optimax rpm fluctuation

Sorry, not sure enough with late models to go any further.. Any luck in the trouble shooting section of the manual?<br /><br />Good Luck!! Clams where are you!!!!
 
V

vstol

Petty Officer 2nd Class
Joined
Feb 27, 2005
Messages
106
Re: 2001 Mercury 150 Optimax rpm fluctuation

I think that the the only possible reason could be the boats fear of flipping during the next fishing trip you turkeys take it on, now give Dave his boat back Nick and go buy your own.
 
R

reeldeelfishin

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Jun 11, 2006
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Re: 2001 Mercury 150 Optimax rpm fluctuation

Hey ****tards, switch your engines around and then your left one will be workin. You may then find that your right engine has problems but at least you fixed the left engine. You guys are so stupid. And for the record, I agree with that ***** vstol, get your own boat. Ask your wife for your balls back and get a boat.
 
N

npanthony

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Re: 2001 Mercury 150 Optimax rpm fluctuation

rdf and vstol seem to be some inteligent people. perhaps one day you will grow up and collect all of your rusted never used tools from the back yard with your kids toys and put them to some good use.
 
studlymandingo

studlymandingo

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Mar 22, 2006
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Re: 2001 Mercury 150 Optimax rpm fluctuation

Have you tried pumping the primer bulb while this is happening? It is possible you need a fuel pump rebuild.
 
W

wilffert

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Nov 8, 2011
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Re: 2001 Mercury 150 Optimax rpm fluctuation

Hi there I just read your post, our I also had the same isue with one of my twin optimax 150 year 2001.
I took it to the dealer and they could not figuer it out so they called the merc rep and when he showed up with his lap top he could not find the solution either.
Right before giving up on this they decided to loose up a little rubber relay on the right hand side of the engine and the problem was gone.
It was picking up the fibration on the engine and made the rpm's fluctuate.

Try it good luck.
 
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