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Message |
    
Ralph Page
New member
Username: ralphp
Post Number: 1
Registered: 06-2009
| | Posted on Thursday, June 25, 2009 - 12:35 pm: | 
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MY motor was running fine and all of a sudden dropped down to 3500 rpm while driving pontoon boat. Can't get it to go beyond 3500 rpm now. any thoughts as to why? Usually operates over 5000 rpm mark. |
ian summerfield
Member
Username: budgie14
Post Number: 11
Registered: 06-2009
| | Posted on Thursday, June 25, 2009 - 05:15 pm: |
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hi,something wrapped around prop?throttle cable adjustment moved?restricted fuel supply?oil level ok?theres just a few.9.16am |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5460
Registered: 05-2007
| | Posted on Friday, June 26, 2009 - 01:31 am: |
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My guess would be the "guardian" system detected a problem (overheat, water in the fuel, oil failure etc) and restricted the rpms.
After checking out Ian's suggestions you are probably going to have to take it in, have it plugged into a computer to see what it spits out... |
Ralph Page
New member
Username: ralphp
Post Number: 2
Registered: 06-2009
| | Posted on Friday, June 26, 2009 - 11:27 am: |
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Thanks for the input. I have checked the prop and nothing is wrapped around. Oil is fine and in fact is brand new. Gas may well be an issue as half the tank was left in over the winter with stabilizer in it. If I siphon out the gas and put new gas in will the motor then work ok without having to take in for service? |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5465
Registered: 05-2007
| | Posted on Friday, June 26, 2009 - 11:51 am: |
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You can try some new gas, might work (maybe). Even stablized gas can deteriorate, in particular it loses octane.
Mix in some premium to give it a "boost", you might get lucky.... |
Ralph Page
New member
Username: ralphp
Post Number: 3
Registered: 06-2009
| | Posted on Friday, June 26, 2009 - 12:38 pm: |
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Will try it first and see if that works. thanks for the input. Will advise either way.I am being told locally that the ethanol bleded gas is causing a lot of difficulty on boat motors and that premium is the best way to go now to ensure smooth running and a little longevity. |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5476
Registered: 05-2007
| | Posted on Saturday, June 27, 2009 - 01:33 am: |
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Ethanol can cause some water problems which is why you should use fresh gas every time out and run stablizer all the time and use a good water separating filter.
On the positive side, E-10 keeps your entire motor cleaner than non-ethanol enhanced gas (it's often the cleaning effect of ethanol that causes the clogs when "cooties" in the lines and components are disloged).
Most motors are designed to run on 86/87 octane.
Running 89 is not bad but pretty much a waste of money (it still contains ethanol and the motor doesn't need the higher octane - but does allow you to "store" the gas for an extra couple weeks before it gets old enough to cause performance degradation).
Running 91 or 93 octane can be downright dangerous (unless your owners manual specifically calls for it - very few mercs and only very high horse ones call for 93) since alot of the "extra" octane is achieved through additives that aren't all that friendly to marine motors.
Trust your owners manual or a bulletin from Merc when it comes to your motor - "some guy" isn't going to pay to fix it when you toast it from taking their advice... |
