2005 Merc 15hp 4 stroke Troubles

[Splash15]

I just bought a brand new 15 hp 4 stroke Mercury outboard and conducted the first day of break in on the engine today. I was extremely careful to follow the manuals break in procedure to a tee. During the second hour of operation you are supposed to run the engine at varying speeds up to 3/4 throttle with 1 min bursts of full throttle every ten minutes. The engine, up to 3/4 throttle is magnificent. It runs smooth and almost as quietly as the trolling motor. However it has a distinct miss from 3/4 to Full throttle. My question is, is this normal? Could it just be the rings seating? or is there something terribly wrong with high end on this engine? If anyone has experience or info with this sort of thing please let me know. Thanks.

 

[hondon]

Re: 2005 Merc 15hp 4 stroke Troubles

You may be triggering the rev limiter on this unit.To find out ,you will need to connect this engine to a shop tachometer and find out what you are turning and if you are over revving.Also ,are we sure the vent is open on the fuel tank?What condition is that boat bottom in?

 

[rodbolt]

Re: 2005 Merc 15hp 4 stroke Troubles

what Hondon says. the prop in the box may not be the correct one. must use a known good tach to insure its in the coirrect RPM range at WOT.<br /> sounds like another back door sale or a gun decked PDI sheet.

 

[Splash15]

Re: 2005 Merc 15hp 4 stroke Troubles

The vent was open on the fuel tank - checked it twice to make sure. The Prop on the motor is the one that came on it from Merc - and the engine came out of a crate directly from the Bass Pro Shops in Cincinnati.

 

[Splash15]

Re: 2005 Merc 15hp 4 stroke Troubles

Oh yeah, it's on a flatbottom boat in perfect condition.

 

[hondon]

Re: 2005 Merc 15hp 4 stroke Troubles

Another crated package.Sorry brother.

 

[Salty Dog]

Re: 2005 Merc 15hp 4 stroke Troubles

"Another crated package.Sorry brother."<br /><br />What does that mean?

 

[gss036]

Re: 2005 Merc 15hp 4 stroke Troubles

I would think what hondon is saying that when you buy a motor in a box from a discount business of this type, you get what you order without any service. Most will tell you to return it the mfg for repairs. Who do you go to for this type of problem. If the motor had come a dealer locally, then you just return it to them and they fix it for you. Kind of hard to get service from a dealer hundreds of miles away on this type of deal.

 

[TOHATSU GURU]

Re: 2005 Merc 15hp 4 stroke Troubles

No, it's not normal. No, it's not the rings seating. It's unlikely that the problem is anything other than fuel system related. You have a warranty that is good at any Mercury dealer, so take it in to one of them and let them deal with it. If it is water or trash from your fuel they will charge you to fix it. If it's a defect in a part or something that was improperly put together Mercury will cover it.

 

[rabidfish]

Re: 2005 Merc 15hp 4 stroke Troubles

I am betting on the prop or the fuel.<br /><br />I am also betting that most of the locals dealers there don't like to work on engine sold by Bass Pro Shops.<br /><br />You need a WOT tach reading, no matter what else you do. It will help determine the correct prop. That will help your engine live longer.<br /><br />As for warranty... My bet is, it isn't registered.<br />Until it is, it's not covered. Welcome to "discount buying"

 

[Splash15]

Re: 2005 Merc 15hp 4 stroke Troubles

Enlighting information from all. Thanks sincerely. It turns out that it is the rev limiter kicking in because it only has a 9 pitch prop. With a full load of persons and gear the 9 pitch is actually probably the best (maybe 9.5) because the engine just gets to WOT without the rev limiter kicking in. Only prob is that when I go out alone I have to be careful to not go above 3/4 throttle.

 

[jjbuoni]

Re: 2005 Merc 15hp 4 stroke Troubles

Get a TAC

I used a "Tiny Tac" on a kicker just to be sure it got me to the full range when WOT.

I bought a full outfit from a dealer and he tested the motor in a tank but never on a lake . Needless to say the prop was not correct. However, I had a tach to help with the proper prop selection and also the proper trim adjustment.