knottysmooches

We bought our boat with the idea that down the road we may drop new engines in. It is a 2006 Formula 280 BR with twin 350s with 400 hours. It is in great shape and we have put about 30 hours on it. The Starboard motor has been giving us some trouble. We put a low and high pressure fuel pump on it a month ago and two weekends ago we had an issue that is still being resolved. Boat besides those issue is awesome and reliable.

Basically we pulled into the lift, shut off the engines and raised the boat. I then went to flush the engines using the muffs. Port engine no problem. Starboard won't turn over. It half cranks and stops. In my hurry (and stereo still cranked up) I figure it is a battery issue flip the switch to give power from both batteries and try to start it. Motor half cranks and zing the starter lets go or something else (possibly fly wheel teeth). OMG somehow it has water in the port cylinder bank. My mechanic pulls the plugs and manually turns over the engine and puts oil in the cylinders. It looks like a flapper was defective. Our action plan is to replace all the manifolds and riser along with the flappers on both engines.

So far we have tried to install a new starter and GREAT new starter is defective. At this point I still don't know if I broke anything in the motor.

I am growing frustrated with the issues. I am consider pulling both motors and installing 383s even if the motor turns out to be fine.

I do NOT have captains call exhaust and the drive is a bravo 3s. I currently run 55 top end with a max of 60 running on fumes and chop.

With the added power (100 extra) will I gain any top end with the bravo 3? I believe that I can switch out just the lower part of the sterndrive to a bravo 1?? What will this do to the handling of the boat?

All told I understand that this will end up costing more then trading it on a newer boat but we really like this boat. The size is perfect and it is in mint shape.

Blueabyss

There should be an internal and external flapper in your through hull exhaust. Pull up the external one and look up the pipe. You need both . If it does not have this or if it is burned out, have it installed. 100 extra HP on bravo 3 will prob be less than 2 mph. But it will get there a lot quicker. Switching to bravo 1 and 100 hp might give you 8-10 mph. Im guessing 66-67 maybe 70 on fumes and 1 person. What motors are you looking at ? 383?

Chris

knottysmooches

Hey Chris,

Thanks for getting back to me. I don't have though hull, exhaust exits out the drive. Your speed numbers are what I was thinking. The boat is a party barge not the best hull for cranking out top end.
There are many different 383 options. Merc has a 350Hp and 400hp crate engine. I have emailed a couple online engine builders. Some clame 425hp but I think I would need though hull.

Any recommendations?

BUP

iTrader: (9)

I have customers that have a 260 BR with bravo I and another with a Bravo III and I have customers with a 280 BR with Bravo III's and Another with bravo 1 's. I would leave the Bravo III's on for these apps. They are both heavy and stern heavy boats. the Bravo III 's on both these apps is a better overall running and handling choice. These are Not fast boat anyways. No offense

Next tip for these apps is - the rub rail sealant for the shoe box fit - top deck to hull lets go. Plexus bonding problem. I have fixed hard to find water leaks into the engine compartment because of this on about 8 Formula's but I think these were from 2005 thru 2007 maybe 2008 was not a problem.

Not sure just giving you a huge tip and a lunch eater for many. I have a funny story on how I found these leaks on the first one and of course the next ones were easy after that because I knew exactly what was causing the mysterious water leak into the engine compartment / bilge area. Formula did or will not put out this info - the first owner tried to get help from Formula years ago after I fixed it and of course charged him for my services. I still have pics of this as well showing all of it.

Next info - Make sure you use Brand new - the OEM grafoil dry joint riser gaskets for your dry joint exhaust manifolds / risers and your tech installs them correctly to a T including torque sequence and torque specs. and then have them recheck after x amount of heat & cooling cycles. .

These dry joint riser gaskets require certain positions upon installing plus they Mercruiser has 3 different versions depending your dry joint exhaust set up. I see these installed wrong a lot and cause problems. Make sure he knows what he is doing here upon installing them.. I promise I know what I am talking about here and hopefully this was not your original problem. Sounds like you had a water shutter that broken off internally in the Y pipe IMO to,. Good luck

Blueabyss

What year are your motors? You may need new risers and manifolds. The flapper being bad in through drive exhaust would be rare to cause that much water in cylinders. I dont even think volvo uses flappers any more. Anyway the 400 hp 383 seem good , above that they can be problematic. This is what I would use and sell your engines to offset the cost.
http://www.michiganmotorz.com/stroke...mpi-p-502.html

I have a friend that took 330hp mpi motors out of a 33 outlaw and replaced them with the 383's above with headers and picked 3 mph. Not a big number but he runs the piss out of them and has had no problems. I am a merc small block fan. I have had several merc big blocks and always had problems. Dont think I was that hard on my last 496 and only got 200 hrs out of it. One of my fishing boats has a 1999 merc 5.0 that I have over 1000 hrs on and we run it harder than I ever did that 496. I have learned that Big block motors with big cams in boats with a molded in swim platform is asking for trouble.

Chris

BUP

iTrader: (9)

Mercruiser still uses water shutters in their Y pipes for exhaust thru the drive,

Water shutters aka flappers or aka flapper valves how ever you want to call them .

Volvo all gas engines got rid of water shutter / flapper valve in 1999 they put out a world wide SB to get rid of them for all Volvo 1996 and up.