posted 05-19-2012 08:25 AM ET (US)            

http://www.bostonwhaler.com/boat_graphics/eprowebsitemedia/2904/ EnginePerformance/268455_EnginePerf.pdf

That report shows a top speed of 40-MPH (or 34.7-nautical-miles-per-hour) for a 190 MONTAUK and a 115-HP engine. You report a top speed of only 22-nautical-miles-per-hour. The ratio of your speed to the Boston Whaler factory speed is

Your Speed/Published Speed = 22/34.7 = 0.634

We know that boat speed is proportional to horsepower-to-weight by the 0.5 exponent, so we can infer the horsepower you are getting by taking your speed ratio and raising it to the exponent 2:

0.634^2 = 0.4 = Your-HP/Published-HP

Now we infer your engine's power ouput as 0.4 x 115 = 46-HP

There is clearly something wrong with the engine.

posted 05-21-2012 10:00 AM ET (US)            

Perhaps more to the point, a friend of mine was having similar-sounding fuel delivery problems with his 190 Nantucket a few years ago. After a lot of investigating, he found that the end of the fuel pick-up tube inside the tank was improperly formed (I think it was kinked, but I forget the exact details) which caused it to occasionally restrict fuel flow with similar results to yours.

posted 05-21-2012 02:20 PM ET (US)            

Sheik- When advancing the throttle, does the engine sound change to a labored or bogging sound?

posted 06-22-2012 02:36 PM ET (US)            

As always, thanks for your ideas. The [cause of the] problem [with poor running of the Mercury FOURTSTROKE 115-HP outboard engine] has been diagnosed as bad fuel. [Unclear] wants me to take the boat out of the water, to their shop, to pump out the fuel (at a high price).

posted 06-23-2012 10:37 AM ET (US)            

Might want to check into that.

posted 06-25-2012 09:14 AM ET (US)            

If you have a primer bulb in your fuel line use it to pump fuel to your engine when it begins to slow or sputter. If you don't have a primer bulb consider installing one. They are useful to move fuel from the tank and as a fault analysis tool. I believe there is an article in the Reference Section that discusses the usefulness of primer bulbs.

If squeezing the primer bulb results in your engine running better there is a good likelihood that your engine mounted fuel pump is defective.

Fuel delivery problems can also be caused by leaks on the suction side of the system which allow air to enter the fuel lines and pumps. This results in fuel starvation with symptoms similar to those caused by fuel pump and or filter problems. You reported that you replaced the fuel filter (element??) this Spring. If you replaced the element you may have crimped the element O-ring. If you replaced the filter assembly you may have leaks at the inlet or outlet fittings. If the primer bulb suggestion is not helpful consider checking the filter.

I'm not familiar with your engine so the above is guesswork. Some engines have both a transfer pump and a lift pump so that may also enter into your analysis.

Good luck.

Butch

posted 06-25-2012 11:34 AM ET (US)            

From there you can prime in fresh fuel and give it a go.

If your gas looks like apple cider, it has some water in it and is going south. If it starts to seperate then you need to get that pure ethanol out along with some water.
(just put some gas from the boat in a glass or good plastic container and let it sit for a few minutes)

From there, I put in a product called isoheet. (2 bucks from Walmart a little more at most autopart stores)

posted 07-01-2012 11:59 AM ET (US)            

Did you ever look at the fuel or drain it?
Pump some of it into a glass container and see what you have?
The under cowl filter may tell you enough.

In my opinion that is the most likely problem in this age of Federal garbage gas.

The pump may have been some the problem, but if the gas is bad, well?
The pump may have been done in by the gas.

When we hook up the trailer and launch, and take off, we are shaking up all the gas and whatever is in it.

The suggestions about the fuel pickup tube are also valid.
Alcohol could have eaten it, or part of it.
And access was not a thought when these things were designed.

Whalerdog. do you have the factory manual for the engine?
My '05 90 carb manual shows a teenee filter in front of each carb.
The injected one may have something like this?

And I have to remove the intake manifold if I want to get to them.
Access was not a thought.

And I could be totally wrong about your situation.

Good Luck!

posted 07-01-2012 12:40 PM ET (US)            

Warranty is toast on this motor at 6 years old.

I don't think on an 07 the alcohol could or should have eaten pickup. I would be disappointed if that is the case. I know from racing Skaters the earlier ones had fuel tank issues but this is an 07. 30 gallons of new fuel in it this morning and it was only 1/4 full.

Water pressure is seemingly down so I have to address that first. I don't feel like doing a water pump today. Mech is off tomorrow so then there is Tuesday and then the 4th so I guess I will be SOL. I feel like wrapping it up and the season never even started.

The Whaler next to me has some old Yamaha engine on it and it runs fine for years. Everything new seems to really be a POS from appliances to tools. Just made to get you out the door and work for a year. I am seemingly surrounded with stuff 2-3 years old with nothing but problems. This just tops it off. I want to get trailer out of driveway and now I look out the back door and see a boat I can't use.

The most important thing is to take my dog for his canal rides. He was all excited and howling when he saw the boat in the water. He was going nuts watching me prep it the past few weeks out through the front door. This morning he jumped in it only to go no where. I'll leave it in the water for the mechanic to run it.

Thanks for the help all!