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2008 Mercury 90 EFI - intermittent loss of power but then runs great
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| waco72 |
Posted on 08/07/13 - 2:15 PM
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I have a 2008 Mercury 90 EFI on my 170 Montauk. 4 times in the past two weeks when running at different speeds it feels as though the engine loses all power but still stays running. During the loss of power, even if I open it all full throttle it sounds as though it is not getting fuel and the rpms stay low. No warning alarms go off. The engine also runs very rough during the episode but quickly recovers.
By shutting the boat off and restarting it or bringing the throttle all the way down it seems to fix it and the boat runs perfectly. As I said it has only happened 4 times in the past 300 miles.
The gas is always fresh and the boat is run approximately 100-150 miles a week. Other than this intermittent issue, it runs great and feels and seems like a new engine.
It seems similar to how my old 2008 40 hp EFI felt when I lost a coil pack twice however the only difference is that this quickly resumes normal operation.
I spoke to the mechanic who does my work and he told me that it would be very difficult to diagnose until it goes completely. I am at a loss since I am basically being told that a breakdown is inevitable.
Any ideas or suggestions for me to look into is greatly appreciated, thanks
Edited by waco72 on 08/07/13 - 2:19 PM |
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| Bossy70 |
Posted on 08/07/13 - 3:04 PM
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I had a very similar issue on a carbed 60hp 2 stroke Mercury. I ended up replacing all the fuel line, the under cover fuel filter, and the transom mounted fuel filter/water seperator. This combo fixed it.
Maybe a fuel filter?
2004 Boston Whaler 150 Sport w/ 60hp Mercury 2 stroke |
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| Phil T |
Posted on 08/07/13 - 3:57 PM
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How many hours run?
When were all filters replaced?
Fuel treated with stabilizer? Y or N
Last spark plug change?
Thermostat change?
I would start your process of elimination.
Running on a clean separate tank, new bulb and fuel line with fresh separator filter is a start.
Clean the vapor separator tank (VST) and replace the fuel filters (should be 2, low speed side and high speed side).
I think those two would eliminate fuel from the equation.
I would guess you have some crud somewhere that blocks flow. When you stop, it moves and the system is ok.
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| waco72 |
Posted on 08/07/13 - 4:14 PM
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[quote]Phil T wrote:
How many hours run?
When were all filters replaced?
Fuel treated with stabilizer? Y or N
Last spark plug change?
Thermostat change?
Thank you for your reply. I bought the boat the beginning of last season and the only thing I have done to it is change the oil and lower end fluid. The fuel has never been treated with a stabilizer and I am unsure how many hours it has on it. I can say with certainty that I would estimate that I have probably put on probably 250-300 the past two years. Prior to that I do not know what has been done. The strange thing is that I get no warning alarms in the Guardian system and it runs perfectly other than those few instances.
Wouldn't I get low fuel alarms if it was related to filters and an impeded flow? I do know that it has been at least 2 years or longer since spark plug change.
Three out of four times it happened it was within the first 5-10 minutes of operation. The other time it happened was after running for about 2 hours, shut it down for half hour then restarted it and it immediately bogged down.
Thank you for the advice, I will definitely have those all changed not knowing the past maintenance on it.
Edited by waco72 on 08/07/13 - 4:17 PM |
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| Bake |
Posted on 08/07/13 - 6:21 PM
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I second (or third) the recommendation to start with the fuel system. Possibly get some quick silver fuel treatment \ cleaner to run through with a tank of gas.
Might as well do something while your waiting on a electrical problem to show up. Although I would put my money on fuel system
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| waco72 |
Posted on 08/18/13 - 10:04 AM
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Thank you everyone for the replies. I have changed the fuel filters and treated the fuel with mercury QuicKleen and the issue is still happening. It happened again yesterday within the first 5-10 minutes of running as it has been just as I began to throttle up and reach about 5000 rpms. I throttled down and after about 15-20 seconds it seemed to correct itself. I then took it out for 10 hours and did 80 miles in total and it ran great and never did it again.
What I have noticed is it seems to do it after not using the boat for 2 days and once it happens within the first 5-10 minutes, it doesn't do it again for several days.
Is it possible that it is something with the computer and sensors that need to be reset by shutting boat down? I am completely baffled and even the local Merc service rep stated that he isn't sure what it could be.
Thanks
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| wing15601 |
Posted on 08/18/13 - 10:07 AM
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Does it smoke when this happens?
I winter in Ft. Myers and summer in St. Joseph, Michigan. It’s now about 12 years since I’ve joined this group. I gave my 1972 whaler to my daughter and sold the 17’. Bought an O’Day 28 sailboat and sailed on Lake Michigan. Yesterday I bought a 2005 130 Sport. |
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| waco72 |
Posted on 08/18/13 - 10:12 AM
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wing15601 wrote:
Does it smoke when this happens?
No it doesn't smoke but the usually very quiet engine becomes louder, shakes a bit and definitely sounds rough but as soon as I shut it down or throttle back, it is back to normal for the rest of the day.
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| mtown |
Posted on 08/18/13 - 10:18 AM
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Have you tried it on a remote tank yet. That will eliminate tank, fuel lines, external filters in one easy step if it still does the same thing on the remote. If it runs fine then you know it is one of the above.
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| waco72 |
Posted on 08/18/13 - 10:32 AM
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I will try the new tank tomorrow. The strange thing is is that if it was related to fuel that I would think (and I readily admit, I know very little about outboard repair) that it would happen all the time and not just within the first 5 minutes. Does anyone know if there are sensors or an internal battery in the engine's computer that may be malfunctioning and by shutting the engine down it resets something in the computer?
After it it happens for the first time, even if I shut the boat down for several hours while we are out or anchored off a beach, it doesn't happen again for a few days.
Thanks again for everyone's input
Edited by waco72 on 08/18/13 - 10:49 AM |
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| waco72 |
Posted on 08/19/13 - 10:16 AM
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I am slowly and hopefully narrowing this issue down. I tried the new fuel and new fuel tank today and had the exact same loss of power between the first 6-8 minutes of running the engine when going from about 2500 rpms to 5000 rpms. So up until now I have changed the 2 fuel filters, tried a fuel additive/cleaner and changed the fuel and the tank.
The only thing that I did differently today was when I lost all power I was at WOT and instead of shutting it down or throttling down, i left it WOT. Within about 5-6 seconds the engine seemed to recover on its own and then ran perfectly for the rest of the day again.
I have not checked the VST as I have no idea how to open or drain it on the engine. Does anyone think that it may just be accumulated water in this VST that is causing the issue? For some reason I thought this was under high pressure and had to be serviced by qualified tech (which is not me by any means)
This is driving me nuts, thanks for any further help.
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| brooks89 |
Posted on 08/19/13 - 11:13 AM
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Doesn't your motor have a diagnostics terminal to allow a technician to scan the ECM for trouble codes? That's where I would start before changing filters, fuel, spark plugs, etc.
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| waco72 |
Posted on 08/19/13 - 11:23 AM
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brooks89 wrote:
Doesn't your motor have a diagnostics terminal to allow a technician to scan the ECM for trouble codes? That's where I would start before changing filters, fuel, spark plugs, etc.
It probably does. When I spoke with the mechanic who I know he said it initially sounded like an electrical issue but after listening to several different members here, many fee that that it may be related to the fuel system. I am only into it for about 30 dollars so far since it needed filters anyways and I had a spare tank.
The engine has the Guardian alarm system but I have never had an alarm during these episodes. Do you think an error code would still be generated even though the incident only lasts less than 10 seconds and no alarm is generated?
Thanks
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| waco72 |
Posted on 09/02/13 - 9:08 AM
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It happened again today at the same time (approximately 5-7 minutes into trip). I was running at about 5500 rpms and all of a sudden it dropped to under a 1000 rpms for about 5 seconds and then corrected itself and ran fine for rest of day. I changed the plugs which were due anyways and mechanic said he would not expect to see any error codes if no alarms were triggered so I haven't brought it in yet. At this point all plugs were changed, ran new fuel from separate tank and changed fuel filters. I do not believe it is fuel line because it is solid and issue only happens once per day. There is a high pressure fuel pump/vapor separator tank than I have no idea what to do with since it seems to be one piece.
Any other ideas?
Thanks
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| wing15601 |
Posted on 09/02/13 - 10:57 AM
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What is strange to me is that your mechanic hasn't seen this problem before. Have you contacted Mercury Marine about it for some advice?
I winter in Ft. Myers and summer in St. Joseph, Michigan. It’s now about 12 years since I’ve joined this group. I gave my 1972 whaler to my daughter and sold the 17’. Bought an O’Day 28 sailboat and sailed on Lake Michigan. Yesterday I bought a 2005 130 Sport. |
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| waco72 |
Posted on 09/05/13 - 5:39 PM
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wing15601 wrote:
What is strange to me is that your mechanic hasn't seen this problem before. Have you contacted Mercury Marine about it for some advice?
Yes, I have attempted to contact them several times by phone and email and this is their response:
Dear Mr. @#$#@
Thank you for the email on your 90 horsepower engine, serial number, 1B521939. We are happy to address your questions.
Unfortunately, due to inherent safety concerns, it is very difficult to diagnose over a phone or email format. If you are experiencing issues with your engine, we would recommend working with your local authorized Mercury Marine dealers. If they have inspected and are having any issues trying to diagnose, then we would encourage your authorized Mercury dealer to contact our factory trained dealer technical service team for assistance. If you need assistance locating an authorized Mercury dealer, we would invite you to visit our website at, www.MercuryMarine.com .
Not much help as you can see
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| mtown |
Posted on 09/06/13 - 5:39 AM
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Just a guess but is it maybe the choke malfunctioning?
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| Silentpardner |
Posted on 09/06/13 - 8:52 AM
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If they have inspected and are having any issues trying to diagnose, then we would encourage your authorized Mercury dealer to contact our factory trained dealer technical service team for assistance.
Can you get it to your authorized Mercury dealer, or is it too far to drive?
The gas is always fresh and the boat is run approximately 100-150 miles a week.
There is a high pressure fuel pump/vapor separator tank than I have no idea what to do with since it seems to be one piece.
I have not checked the VST as I have no idea how to open or drain it on the engine.
You could have a lot of things happening in a motor and boat that is getting run that hard. They have a diagnostic procedure that they are apparently not going to share with you for free. You might be money ahead to get yourself a Mercury service and shop manual for your motor.
Edited by Silentpardner on 09/06/13 - 4:02 PM |
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| whalernut207 |
Posted on 09/10/13 - 5:16 PM
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My father had the very same issues you are having on his 17 Montauk. not sure what caused it either? he heard some story that ethanol was breaking down fiberglass tanks and that was causing the problem. I don't really believe that story. anyway 2 shops later we got a plastic tank and just ran a new hose over the deck to the motor directly. we bypassed all the filters ect. for whatever reason that worked! we then went over the fuel system and replaced everything. things seemed fine after that. I think somehow the fuel system was sucking air somehow. he has since sold the boat so not sure how it is holding up. I am not a mechanic but we were desperate as no one could figure it out. we checked the stater and many other electrical parts to no avail. hope this helps let me know if you figure it out.
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| waco72 |
Posted on 09/15/13 - 6:06 PM
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whalernut207 wrote:
My father had the very same issues you are having on his 17 Montauk. not sure what caused it either? he heard some story that ethanol was breaking down fiberglass tanks and that was causing the problem. I don't really believe that story. anyway 2 shops later we got a plastic tank and just ran a new hose over the deck to the motor directly. we bypassed all the filters ect. for whatever reason that worked! we then went over the fuel system and replaced everything. things seemed fine after that. I think somehow the fuel system was sucking air somehow. he has since sold the boat so not sure how it is holding up. I am not a mechanic but we were desperate as no one could figure it out. we checked the stater and many other electrical parts to no avail. hope this helps let me know if you figure it out.
Thanks for the info. I have tried everything now and even the certified Mercury tech who I know and trust is at a loss at this time. It did it again today, lost all power for 5-10 seconds then corrected itself and ran great for another 50 miles. I was hoping to get it squared away before I am done for the season up here but cooler weather is moving in and I am not sure that I will.
Edited by Joe Kriz on 09/15/13 - 6:26 PM |
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