Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

[hujikol]

Hi.
I have bought a 1998 Chaparral 260 Signature, 7.4 mpi Mercruiser and a Bravo I sterndrive, and the question is:
Is it normal with a Bravo I on this type of boat???

The boat won't plane out if we are more than 4-5 persons onboard, and the max speed is no more than about 30 mph.

Best regards, Kenneth

 

[Dave1251]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

The boat should plane out with the bravo one. Many boats this age have bravo ones and with the mpi 454 it should plane easy and have a max speed close to 50 mph.

There has to be something wrong either from prop size, engine performance, or bottom growth. What RPM is the engine running at WOT. It should be somewhere between 4,400 to 4,800 RPM.

 

[TilliamWe]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

Hi.
I have bought a 1998 Chaparral 260 Signature, 7.4 mpi Mercruiser and a Bravo I sterndrive, and the question is:
Is it normal with a Bravo I on this type of boat???

No. A Bravo 1 is not normal for a cruiser like that. A Bravo 2 or Bravo 3 is what it would have come with.

It should still plane with a Bravo 1, unless you have some weird, funky, small diameter or clever style prop.

 

[AZSenza]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

I would agree with the Bravo III. 22+ foot cruisers are really what the III was designed for. The I was for big horsepower fast, light boats. the II was for large barge type boats with maybe a diesel. Still, unless the gearing in the drive is completely wrong, it should do fine. I would ghuess maybe it needs s tune up? plugs and cap. The key is how many RPM's are you turning, that will decide the troubleshooting tree.

 

[TilliamWe]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

AZ, just to help you a little, the Bravo 2 was originally designed for cruisers just like this 26' Chaparral. Not necessarily for diesels or any of that, or barge type boats. Just "big ol' heavy cruisers" that needed a huge amount of blade area to develop maximum thrust. And it was quite popular on boats like this one, until everyone started to ask for the Bravo 3.
As a note, there is a Mercruiser Certified mechanic here in Peoria that swears that boats like the couple of 39' - 40' cruisers that we have in our harbor, equipped with Bravo 3 sterndrives, instead of B2s, are in for trouble down the road. He claims/swears that the larger propshaft and bearings in the Bravo 2 is a much better fit for a huge heavy cruiser liek those boats. And that someday, those B3s will just "wear out". I don't completely agree, but his concern is somewhat valid.
huj, you need not worry about "wearing out" your Bravo 1, it'll handle the load. You need to troubleshoot your issue and narrow it down to prop or engine issues. Good luck.

 

[hujikol]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

Thanks for your answers!

The RPM tops at 3800-4000, so maybe I have an engine problem.
I thought the problem was a wrong gear ratio or so, but as I understand your answers, the Bravo I will work. It's somewhere else I'm loosing power???

I'm not sure, but I think the prop size is 17" - so it's not because the prop is too big I guess?

(sorry for my english, i'm danish and live in Greenland)

 

[TilliamWe]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

The RPM tops at 3800-4000

I'm not sure, but I think the prop size is 17" - so it's not because the prop is too big I guess?

(sorry for my english, i'm danish and live in Greenland)

I follow your English perfectly, no worries there.

Confirm that your tachometer is reading correctly.

A 17 pitch prop should be just about correct, yes. The low RPMs indicate you have an engine issue. But it still would be helpful to know what the drive ratio is, and what type of prop it is, what condition it is in, and maybe a photo of the drive and prop.

 

[hujikol]

Re: Chaparral 260, Mercruiser 7.4 mpi, Bravo I????

OK...i'll try to find out asap...