Yamaha 2005 115 2 stroke Problem

[stern]

Hi Guys,
new to this forum and hoping you can help and arrest my concerns. Just took delivery of a newish boat with a 115 2st and have taken it out for the first time. Out of the water it seems fine but once in the water, it is very sluggish (struggling to get over 10 knots) at full throttle. Also, its emitting strong (unbearable) fumes. The outboard has just done over 20 hours and therefore, its a concern. I have booked it in for a service next week but was worrying about it so I thought I would ask the question.

thanks in advance

[stern]

thanks,
unfortunately purchased privately but its under warranty...any idea what it might be?

[jonp]

Hi Stern,

It May be a few things, could you share more info on the boat, prop size, and weight. Also do you mix oil or does it have oil injection? What was it rebuilt? You mention it has 20 hours.

Jon

[stern]

thanks JonP,
its 20hours new (not rebuilt), its a 5.2 mtr glass bowrider (weight of boat is around 450kgs)max rated to 130hp - max transom weight is 225kg..oil injected..sorry not sure of prop size but think its the standard for the model.

[jb123]

smell= bad fuel pumps

[jonp]

Hi Stern,

I agree with JB, it does sound like a fuel delivery issue. I would approach this by process of elimination, starting at the fuel tank. Check hoses, connections, and filter/separator if you have one, then the fuel pump etc... Pump is relatively inexpensive and should be replaced every few seasons.

Also based on the weight of you boat (about 1000LBS) you probably should close to a 21-inch pitch

This a good link for props

http://sites.mercurymarine.com/porta..._schema=PORTAL

good luck

[jb123]

bad fuel pump will dump fuel right into crankcase and out thru prop.
could also need carb cleaning.
pull each plug wire while running on hose at around 1200 rpms, see if all produce drop in rpms as a nonfiring plug could cause symtoms like this also.

[stern]

thanks guys
really appreciate the assistance on this forum...just one last question...someone suggested it could have been a poorly trimmed outboard...as Im new to boats, that would be a possibility...are the symptoms consistent with this?