CCP Owners - Question about brackets

[Evan337]

We have 1988/89 250 CCP. It came from the factory with a closed in transom and a bracket. We are the third or fourth owner of this boat. One of the previous owners lowered the bracket by 2 inches. We currently run twin 150 evinrude etecs. Everything is fine when running in smooth water to moderate chop. When we run in rougher waters the starboard engine cavitates regardless of engine trim, trim tabs or speed. There is a scupper for the live-well on the starboard side. We have theorized that the scupper may have something to do with it.

Did the bracket come from the factory mounted too high? Should we lowered the bracket again? or lower the engines? Anyone else experience this problem?

We're considering a new flotation bracket if we can't get this thing dialed in.

[wingtime]

You need to see how the engine are running on a plane.  The best bet is to mount a gopro camera on the bracket and take a video of the lower units.  The cavitation plate should be running right on top of the water.   What length shafts are the motors and what mounting hole are they mounted in?

[Evan337]

The engines have 25" shafts and are mounted on the top hole. They have room to move down if needed. I like the go-pro camera idea.

[RickK]

There is a scupper for the live-well on the starboard side. We have theorized that the scupper may have something to do with it.

Are you talking about a raw water through-hull pickup ("clamshell")?  A scupper is a drain for water and is usually on the transom.

[Evan337]

That's right. It's a raw water, through the hull pick-up. It's dome shaped and not flush with the bottom of the hull. We think that the turbulence it causes in the water in front of the starboard engine may add to the cavitation problems. Is that possible/ a common problem?

[fitz73222]

How far in front of the engine is the clamshell?

[Capt. Bob]

We have 1988/89 250 CCP.

I remember this boat. I was curious as to where the hull was built but never found out. It looks like a Hialeah hull but it also looks like a factory closed transom setup. Models in "1990" appear from documentation and a few photos I've seen, came with a factory enclosed transom and bracket. I believe long time member "Doc" has this model so:
Yes, it came that way. That then begs the question,

One of the previous owners lowered the bracket by 2 inches.

Why??

Did the bracket come from the factory mounted too high? Should we lowered the bracket again? or lower the engines? Anyone else experience this problem?

If you are sure someone lowered the bracket, I'd tend to trust (a  little more than a previous owner) the factory and try moving the bracket to its original location. I was always under the impression that the goal of the bracket was to allow a "higher" mounting position for the outboards (due to the setback) for better performance therefore lowering the bracket even more is counter intuitive to the bracket design. Have you checked the offset between the "cavitation plate" and the hull? Measuring is a start but as stated earlier, an actual visual while underway is needed for true running depth conformation. What is the bracket offset from the transom itself (something like 26" for example)?

I ran a single on a full bracket for many years with no major problems but that's not a true comparison.

We're considering a new flotation bracket if we can't get this thing dialed in.

Well the bracket you currently have looks like it has some flotation to it. I'd be inclined to monkey with it (again placing it back where it originally was if needed) before committing to more expense.

I can't recall anyone posting about the clam pickup causing any problem but that does not mean it isn't. I'd look closer at your trim tab mounting also.
Just a thought.

Good Luck.

[Evan337]

Thanks for all the feedback guys. This forum is a great resource.

Fitz,

The through the hull raw water pick up is 40 inches from the Starboard engine and right in line with the engine.

Bob,

The bracket is 27 inches deep from exterior edge of the transom to the exterior edge of the mount plate on the bracket. We have thought about raising the bracket as well back to where it was located from the factory. You can see the old bolt holes where the bracket was mounted before it was moved. I take some pictures and post when I get a chance.

I think the reason we stuck a piston last Saturday is because we were running in rough water, cavitating, which raised the temperature internally and we were running in the mid RPM range 2500 - 3000 rpms. We have considered a repower but got a quote of $33,000 on new twin 200 etecs and used in the $10,000 - $12,000 range. The five year warranty being offered on the new ones is what is so attractive.

If we can solve the cavitation problem we should be able to get more life out of the Fichts. At least a season or two. Mechanically they haven't given us a problem until the last weekend. We just sorted through the mapping, the fuel lines, the throttle cables, etc.

The problem is that we have had 3-4 trips to the coast in the last 12 months where the engines didn't start after we launched or like the last trip crapped out on us once we were out. Needless to say we don't have a lot of confidence in these engines at the moment.

[Blue Agave]

That's right. It's a raw water, through the hull pick-up. It's dome shaped and not flush with the bottom of the hull. We think that the turbulence it causes in the water in front of the starboard engine may add to the cavitation problems. Is that possible/ a common problem?

Absolutely the thru-hull could be interfering. The million dollar question is, was the thru-hull installed at the factory or by the previous owner?

[wingtime]

I think the general rule is the motor can go up one inch for every foot back from the transom.  I was trying to find a nice drawing from Mercury on motor mounting height but i can't find it.

Edit: this looks like some good information:  http://www.dadmarine.com/twin.html

[Evan337]

Blue Agave,

We (my dad) installed the through the hull. It keeps new raw water flowing into the livewell while we're cruising. He has talked about changing it out to a through hull that is flush with the bottom of the hull. That maybe the first thing we should change out before doing anything else.

[kaptainkoz]

I too am looking to mount a bracket on my 79 246 CCP. I googled a few sites and a prior poster is correct that with a bracket, your cavitation plate should be 1 inch above the bottom of the boat for every 10-12 inches of setback. So with a 26 inch bracket your cavitation plate (the flat plate on the lower just above the propeller) should be 2-3 inches above the bottom of the boat. I would think the lower the floatation bracket the more the buoyancy. See if you can move the motor so it sits right before you go through the headache of moving a bracket.