Bayliner Capri bogs down under Full Throttle

[MerriamMagician]

Howdy,

I purchased a used Bayliner Capri 19.5 a few summers back. I believe it is a 2007 model and was used sparingly and well maintained before I bought it. Its ran pretty great in general, however late last summer I had some issues where the boat would sometimes bog down. It usually happened when the boat was at full capacity for people or when towing tubers and wakeboarders. With the throttle wide open it would only go at about half of its normal speed and could audibly sound like the engine was bogged down.

The engine is a 4 cylinder 3.0 mercruiser stern mount. My best guesses are it is something to do with the fuel system. My plan was to try to replace the fuel filter, fuel pump, and spark plugs. Also going to clean out the carburetor. I'm not all that mechanically inclined, especially on boats, so I'm not sure what else to try besides that. I'm ordering parts this week and will be making the replacements soon. If anyone has further input on ideas or have ran into similar problems with this type of boat, I would definitely appreciate any further input.

Thanks! 

[CP]

My bet would be on the carburetor.  Varnish in the jets.  But that’s just a guess.

[jay.sharkbait]

I’d start with the fuel/water separator.

[Stein]

I agree, start with the fuel system.  If it's been stored it's probably 98% certain they didn't use non ethanol fuel and you have varnish.

It could also be under powered or over propped if it's running well except when under a big load as you described.  There are prop websites where you can put in rough numbers and see if it has a reasonable prop.  Sometimes guys will go too aggressive looking for top speed and then you can't get on plane when you load them down.

[kingmountain]

Change the fuel filter, pour the fuel into a clear container. Check the sample for water. More than likely the carb needs to cleaned out, rebuilt. I do several of these a year.