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Mystery brand new BF150, low speed, high consumption, no error?

islander17

New member
Hi,

I have a new boat with a Honda BF150, consistently running about 3-4 knots too slow at WOT and using about 25-35% too much fuel, compared to identical boats/engine/prop from the same manufacturer. Max RPM is fine (5500) and same as the next boat.

The next identical boat does 36 knots/5500 RPM with a clean bottom at WOT. I get the same RPM but I'm lucky to get 32 kn, clean bottom. Local Honda chief mechanic hooked up their computers during a run but couldn't find anything wrong. Before their test, they pointed out that the boat had accumulated quite a bit of growth, but then again they only managed to get it to 30 knots at WOT which is even worse, and probably due to the growth. Max RPM was still 5500, and they wanted a clean boat before having another look at it.

Questions:

- If you lost as much as 30% power (30/36 knots raised to a power of two) due to extensive growth or dragging something, wouldn't the max RPM drop? At least some?

- Is it possible to have e.g. one cylinder not working of a BF150 without hearing/feeling it, and without Honda finding it out when hooking up to a computer?

I'm obviously under warranty from Honda, but it's been several months and things aren't progressing very quickly. I feel like I have the speed of a 115 HP with the fuel delivery of a 150 HP. Any suggestions are welcome.
 
Islander17, you ever able to get your boat performing correctly? I'm having a similar issue and am curious to know what you found out.
 
Mechanic is spot on, you can't check performance with growth on the hull, what have you got against cleaning it?It's extremely detrimental to both performance and fuel consumption
 
Islander17, you ever able to get your boat performing correctly? I'm having a similar issue and am curious to know what you found out.
Not really. I had the BF150 tested (out of water) and it produced an impressive 160 HP, so the problem is likely related to the hull.

We looked into -everything-, and there were some issues with the hull that were ultimately fixed, but the boat still doesn't perform according to specs. I'm bothered by it, but the boat takes me where I need to go.
 
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