New Boat - Bogging down unless....

[InvisibleMask]

I have a 23 LSV with the Monsoon 340 (2008). Only a few hours on it.

It runs fine except when I putt around under 10 mph or even at no wake speed and then give it throttle it often would bog down like it has no fuel. Eventually it would kick in and run fine after throttling it for 10-20 seconds and at full speed its fine. Then when I get back to very low speeds for more than 5 minutes it would do it again at take off. It did this maybe 6-7 times during the weekend.

I decided to run the blower at low speeds just to get air circulating in the engine compartment and that solved the problem. Never did it again with the blower running.

Another thing to note, while driving the boat at 30mph or so I can smell exhaust fumes which I thought was odd. Thinking its new and stuff heating up for the first time I ignored it & it wasn't all the time.

So now I'm wondering if there is some exhaust leak in the engine compartment causing it to not get enough fresh air and the blower takes care of it.

Also, I couldn't get the boat over 39mph with 1/2 tank gas and 4 adults (smooth water) and nothing really heaving stored away.

Any other ideas of what could cause this?

[chuckc983]

Sounds like it could be vapor lock - See if you can find some gas with no ethanol and maybe add some sta-bil, as for top speed - that really depends on what prop you have - if you are turning 5200 RPM at 39 MPH - you probably have a 1235 prop. Most people prefer this as it allows you to load the boat down for surfing. If you don't load the boat down and want more speed - I am sure someone would swap props with you.

[InvisibleMask]

The second day out I did put in about $70 more fuel from a different station and went with 91 octane. I guess its possible that I thought the blower solved the issue but maybe it was the initial gas that I bought was the issue and the new gas is really what improved things on the second day. That may be a stretch though because as soon as I hit the blower switch (roughly 2 minutes later) the problem never occured again. I'm pretty convinced its starving for air for some reason.

[CedarLakeSkier]

... as for the 39 MPH, is that the speedometer or is that with a GPS. You may just need to calibrate the speedometer.

[InvisibleMask]

Speedo. Assuming since its a brand new boat that its been calibrated.

I don't need it faster, just wanted to see if it was normal. I thought I read they average 44mph.

[InvisibleMask]

Here is an update to this problem I had with the boat bogging down unless the blower was running.

Turns out that the big rubber hose on my exhaust manifold had a 1/2 hole in it. Water and exhaust was shooting out of it and when going 1-5 mph the engine compartment would fill up with fumes and cause the boat to starve for air. Turning the blower on forced in fresh air OR moving at a good speed would clear the area out so it ran fine at that point. Although I don't really know how much water was spraying over the engine all this time. The boat now has about 9 hours on it so it happened that whole time until I decided to open the hatches and actually look at the engine while it was running on the lake.

Before putting it in the water I checked over everything really good and just didn't notice the hole in the hose. Its real tough to see unless its running.

I don't know if it was a cut or if it was a defect in the rubber hose which just blew a hole in it under pressure.

$20 hose fixed the problem and boat runs great now.

Oh, and now the boat goes just over 43mph now so this problem also affected my top end.

[Pscott]

I too was having this same problem on my 08 VTX with only 17 hrs- low power and exhaust smell. I mention this problem to two dealers and they could not give me any mechanical reason or solution. " The low power would only occur as we attempt to pull a skier, taking some 6-10 seconds to plane the boat. Since taking the boat to a dealer is a 90 mile trip and a "PITA" I wanted to figure this problem out before I committed to the dealer. Being a new boat, I didn't figure out the connection with the exhaust smell and lack of fresh air to the engine. After reading this forum I instantly felt around my exhaust hoses and found a small hole underneath one. Problem solved, replaced the hose myself ($25 part) and power is back!

Thanks InvisibleMask and The MalibuCrew forum.