2005 Mercury 90HP four Stroke EFI

[spermwhale]

I have a 2005 Mercury 90HP four Stroke EFI that I purchased on a 17' boston Whaler summer of 2005. Only have about 25 hrs on it. Had the 10 hr maintenance done on it by a certified mech. and winterized end of 2005. Beginning summer of 2006, I've started having quite a few problems with the engine.

Here is what is happening, when I try to start it with a full tank and primer bulb hard it will turn over and it may start for a minute or two. Then it will put out on its own or if I put it in gear it will cut out immediately. I've checked the filters (they are clean), there is no water in the water separator, I've tried different gas tanks, changed the gas and even the lines, and I've tried engine starter spray. It acts as if it is starving for gas at times and other times it seems to rev and die.

Took it in the first time this summer, first they (certified Mercury service technician) thought it was the fuel line/primer bulb which it wasn't then they said it was a fuel issue. The ethanol in the gas which led to them rebuilding my carborators (of course a non warranty problem). Got the boat back end of August, used it a couple times and still have problems. Now it won't start and the same mech is giving me the same cause even though I have not been using ethanol gas. In MD different counties have different regulations. I'm looking for any recommendations or suggestions as what my problem could be or if other similar four stroke outboards are having the same problem.

I've talked to many people and no one seems to be having this kind of problem with the enthanol and their engine in my area (solomons, MD). I've finally gotten it out of the water (tow) and I'm taking it next week to a different technician on Eastern Shore (couple hrs away) but want to do my research first.


any insight would be greatly appreciated! Main reason for buying new boat/new engine was for the reliability...

[dnman]

Well I have been an outboard tech for 20 years and sounds like you need to take it to a better mechanic,there are lots of things that could cause this and sounds like a warranty problem...the one thing you dont want to do it start "adjusting things your self"you will only make the techs job much harder,for instance a 90 EFI doesnt even have carburetors?A ball park Idea of whats wrong would be fuel pump not working right...restriction in gas tank...fuel injectors clogged by non use or sitting at dealer waiting to be sold or even deposits left by too much fuel stabilzer...shift switch...just plain old warranty problem...These are great motors I have one and it is one of the best engines out there...get a better mechanic and use it alot,run it some in the off season and dont add any aftermarket additives to fuel ...hope this helps...

[pyro]

I have talked to quite a few people with smaller Merc 4-strokes, mostly 25 HP, who have experienced cutting-out problems. My parents' 25 sometimes just bogs down and quits, usually at or near WOT. Starts back up and runs, then does it again later on. My friend's 25 on his parents' pontoon does the same thing every now and then. Plugs, fresh gas, etc, all supposedly "fixed" them, but the problem would still come back occasionally.

I really want to know what's going on with these motors...

[spermwhale]

Thanks for the input. I'm taking it back up to the dealers service manager to take a look at. They've had a lot of similar problems on their 90HP fourstrokes and said a lot of mechs are causing more problems than fixing. Also I found a thread on continuouswave.com with a lot of people having the same symptoms but no resolution. Several are thinking design defect, others think more vigilant care and maintenance but that was one of the perks of this boat (170 Montauk)- hose her off, give her clean gas, check the oil and she's ready to go.

I don't know much about these engines but the first summer we had it ran like a champ and very quiet. I'm not touching a thing. I've learned my lesson the hard way in the past. We'll see what the next mech says...a couple hundred dollars later.

[NNT]

Whats the Serial number on that engine?I have a buddy of mine who can run it and find out if there's any recalls or tech bulletins on it.

[150aintenuff]

take it to a yamaha tech... its a yamaha built engine and they would be more intune to the issues than a merc mechanic as merc mechanics still havent from what ive seen really put enough real time repair time on the 4 strokes... but thats my area... that may be different across the country..

[1BadAction]

I have a 2005 Mercury 90HP four Stroke EFI .... rebuilding my carborators

:confused: :confused: http://img107.imageshack.us/img107/6170/bsflag.gif

[pyro]

he's getting an asspacking from the dealer doing the service.

[1BadAction]

im with NNT. whats the serial number?

.

[spermwhale]

I was out of town this weekend. I'll send the serial number tonight. Thanks!

[fuelbuster]

Mercury Mercruiser's website has some really good info on precautions with ethanol fuels (E10) in their outboard engines.
- go to mercruiser's website and look for the "ethanol" pages, look for page called ethanol2#1370.
(Let me know if I can post the exact link here).

There's several other websites,
that can help you out with the new changes in "fuel system management" needed when running on alcohol fuels in marine engines.

Listing all the (ethanol) precautions, tips, history, marine studies, etc. here, would take too long. I'll chime in later on in some of the ethanol threads here.

Also very interesting is the 2003 government study done, that compares the effects of 10 and 20% ethanol in Mercury outboard engines.
This study is called, "Marine Outboard Driveability Assessment to Determine Impacts of a 10% and 20% ethanol Gasoline Fuel Blend..."
(Let me know if I'm allowed to post this link, too).

As you probably already know it's only legal and safe to add 10% or less ethanol alcohol to gas (public gas stations).

MANY people are having problems, mainly because the delivery truck drivers that add the ethanol in at the pump, incorrectly, and added more than 10% - Over 10% will cause both performance issues and later serious engine damage.

(Note: Ethanol can't be added in at the refinery due to risk of water contamination in the pipelines).

If you think it's the gas alcohol concentration, that's causing your problems, use an "alcohol fuel test kit" to verify gas has 10% or less alcohol.
There's a few other simple measures you can take to make sure you're only buying and running on good gas - I'll post them all later, but most important is to always use fresh, stable, good gas.

I recommend using higher octane too with E10, as a safety measure, but that's just my opinion, not the official recommendation from any of the marine manufacturers (yet).

Higher octane gives you extra protection in the event the gas you're running on becomes contaminated with water (phase separation), which can lower octane as much as 3 points.

Of course, once gas is PS/WC, your only (safe) option is to discard it and start over with fresh fuel -
Forget the "miracle products" that use deceptive marketing to try to convince you they can "fix" bad gas, and make it "good as new again", (they can't - not possible from a scientific, chemical standpoint).

E10 fuels enter a phase-separated (water-contaminated) state in only 100 days - Therefore try to use gas within 90 days or less, buy from busy stations (gas replacement is faster, fresher)....

BTW, this year, almost all the major marine manufacturers, issued bulletins that state something like, "we recommend you use alcohol blended (ethanol 10% or less) gasoline in your outboard within 30 days...Do not use gas that has been stored in the tank for over 90 days..."


Maryland, does not require the pumps be labeled that ethanol was added.

The following states, DO NOT REQUIRE PUMP LABELING:
(2006 State Laws)

California
Colorado
District of Columbia
Hawaii
Illinois
Indiana
Kansas
Kentucky
Maryland
Michigan
Minnesota
Missouri
Nevada
New Jersey
North Carolina
Ohio
Oklahoma

Only 8 states currently ALWAYS require pumps be labeled when ethanol is added. The other state laws vary depending on amount of alcohol that is added.

[rockdamage]

whats the name of the retard that tried to fix it? you know the rebuild the carbs guy . we need to call this idiot

[alana]

get a fuel pressure test done, i had a 115 efi and had to smile when the expert looked for the carbs to balance them